/* ==========================================================================
   Cloud Launchpad Academy — course platform stylesheet
   Vanilla CSS, no framework, no build step. Shares its design tokens and
   glass treatment with the Cloud Launchpad application site, so the two
   feel like one product family — then diverges where a documentation
   platform has different jobs to do: long-form reading, code, navigation.

   Contents
     1.  Design tokens
     2.  Reset & base
     3.  Layout primitives
     4.  Background (aurora)
     5.  Glass surfaces & buttons
     6.  Site header
     7.  App shell (sidebar / main / toc)
     8.  Sidebar navigation
     9.  Table of contents
     10. Breadcrumb & lesson pager
     11. Homepage — hero, roadmap, module grid
     12. Progress (bar + ring)
     13. Lesson content — header, prose, callouts
     14. Code, terminal & command blocks
     15. File tree
     16. Tabs & accordion
     17. Checklist & quiz
     18. Git-history mapping
     19. AWS / tech service badges
     20. Architecture diagrams
     21. Command palette (search)
     22. Footer
     23. Responsive
     24. Reduced motion & print
   ========================================================================== */

/* 1. Design tokens ------------------------------------------------------- */

:root {
  --bg:            #070b16;
  --bg-deep:       #04060e;
  --surface:       rgba(255, 255, 255, 0.045);
  --surface-solid: #0e1424;
  --surface-hi:    rgba(255, 255, 255, 0.075);
  --border:        rgba(255, 255, 255, 0.10);
  --border-hi:     rgba(255, 255, 255, 0.20);

  --text:          #e9edfa;
  --text-muted:    #98a3bd;
  --text-faint:    #6b7793;

  --brand:         #6ea8ff;
  --brand-2:       #a37bff;
  --brand-3:       #3fe0c5;
  --brand-soft:    rgba(110, 168, 255, 0.14);

  --ok:            #38d39f;
  --warn:          #f5b544;
  --danger:        #ff6b81;
  --info:          #6ea8ff;

  --gradient:      linear-gradient(100deg, #6ea8ff 0%, #a37bff 48%, #3fe0c5 100%);
  --gradient-soft: linear-gradient(140deg, rgba(110,168,255,.16), rgba(163,123,255,.10) 45%, rgba(63,224,197,.10));

  --shadow-sm:     0 1px 2px rgba(2, 6, 20, .30);
  --shadow-md:     0 12px 32px -12px rgba(2, 6, 20, .65);
  --shadow-lg:     0 34px 70px -28px rgba(2, 6, 20, .85);
  --glow:          0 0 0 1px rgba(110,168,255,.22), 0 18px 48px -20px rgba(110,168,255,.45);

  --radius-sm:  10px;
  --radius:     16px;
  --radius-lg:  24px;
  --radius-xl:  32px;

  --gutter:     clamp(1.1rem, 4vw, 2.25rem);

  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
          "Noto Sans", "Liberation Sans", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", "Fira Code",
          Menlo, Consolas, "Liberation Mono", monospace;

  --ease:      cubic-bezier(.22, .61, .36, 1);
  --ease-out:  cubic-bezier(.16, 1, .3, 1);

  --blur:      18px;

  /* Documentation-platform layout tokens */
  --header-h:      3.75rem;
  --sidebar-w:     17.5rem;
  --toc-w:         15.5rem;
  --content-max:   42rem;

  color-scheme: dark;
}

[data-theme="light"] {
  --bg:            #eef1f9;
  --bg-deep:       #e4e9f5;
  --surface:       rgba(255, 255, 255, 0.72);
  --surface-solid: #ffffff;
  --surface-hi:    rgba(255, 255, 255, 0.92);
  --border:        rgba(18, 28, 56, 0.10);
  --border-hi:     rgba(18, 28, 56, 0.20);

  --text:          #101728;
  --text-muted:    #4d5872;
  --text-faint:    #6e7a95;

  --brand:         #2f6bdd;
  --brand-2:       #7a45e8;
  --brand-3:       #0f9c88;
  --brand-soft:    rgba(47, 107, 221, 0.10);

  --gradient:      linear-gradient(100deg, #2f6bdd 0%, #7a45e8 50%, #0f9c88 100%);
  --gradient-soft: linear-gradient(140deg, rgba(47,107,221,.10), rgba(122,69,232,.07) 45%, rgba(15,156,136,.08));

  --shadow-sm:     0 1px 2px rgba(16, 24, 56, .06);
  --shadow-md:     0 12px 30px -14px rgba(16, 24, 56, .28);
  --shadow-lg:     0 34px 70px -30px rgba(16, 24, 56, .34);
  --glow:          0 0 0 1px rgba(47,107,221,.18), 0 18px 44px -22px rgba(47,107,221,.40);

  color-scheme: light;
}

/* 2. Reset & base -------------------------------------------------------- */

*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 1.25rem);
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.65;
  letter-spacing: -0.005em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color .45s var(--ease), color .45s var(--ease);
}

h1, h2, h3, h4 {
  margin: 0;
  line-height: 1.15;
  letter-spacing: -0.03em;
  font-weight: 640;
  text-wrap: balance;
}
h1 { font-size: clamp(2.1rem, 4.4vw, 3.1rem); line-height: 1.08; }
h2 { font-size: clamp(1.5rem, 2.6vw, 1.9rem); margin-top: 2.5rem; }
h3 { font-size: 1.22rem; margin-top: 2rem; }
h4 { font-size: 1.02rem; letter-spacing: -0.01em; margin-top: 1.5rem; }

p { margin: 0 0 1.1rem; text-wrap: pretty; }
ul, ol, dl, dd { margin: 0; padding: 0; }
li { list-style: none; }
a { color: inherit; text-decoration: none; }
img, svg { max-width: 100%; }
strong { font-weight: 620; }

code, pre, .mono, kbd {
  font-family: var(--mono);
  font-size: 0.86em;
  font-variant-ligatures: none;
}
:not(pre) > code {
  background: var(--brand-soft);
  border-radius: 5px;
  padding: 0.12em 0.4em;
  color: var(--text);
  white-space: nowrap;
}
kbd {
  display: inline-block;
  padding: 0.1em 0.5em;
  border-radius: 6px;
  border: 1px solid var(--border-hi);
  border-bottom-width: 2px;
  background: var(--surface-hi);
  font-size: 0.8em;
  color: var(--text-muted);
}

::selection { background: rgba(110, 168, 255, .32); }

:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 3px;
  border-radius: 6px;
}

.sprite { position: absolute; width: 0; height: 0; overflow: hidden; }
.icon { width: 1.05em; height: 1.05em; flex: none; display: inline-block; vertical-align: -0.16em; }
.icon.flip { transform: scaleX(-1); }

.skip-link {
  position: fixed;
  left: 50%;
  top: 0.75rem;
  transform: translate(-50%, -160%);
  z-index: 200;
  background: var(--surface-solid);
  border: 1px solid var(--border-hi);
  color: var(--text);
  padding: 0.6rem 1.1rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  transition: transform .25s var(--ease-out);
}
.skip-link:focus-visible { transform: translate(-50%, 0); }

.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* 3. Layout primitives ---------------------------------------------------- */

.shell {
  width: 100%;
  max-width: 1180px;
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.gradient-text {
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .55rem;
  font-size: 0.76rem;
  font-weight: 650;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--brand);
  margin-bottom: .85rem;
}
.pulse {
  width: .5rem; height: .5rem; border-radius: 50%;
  background: var(--brand-3);
  box-shadow: 0 0 0 0 rgba(63,224,197,.6);
  animation: pulse 2.4s var(--ease) infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(63,224,197,.55); }
  70% { box-shadow: 0 0 0 .55rem rgba(63,224,197,0); }
  100% { box-shadow: 0 0 0 0 rgba(63,224,197,0); }
}

/* 4. Background (aurora) -------------------------------------------------- */

.aurora {
  position: fixed; inset: 0; z-index: -1; overflow: hidden;
  background:
    radial-gradient(1100px 620px at 82% -10%, rgba(110,168,255,.16), transparent 62%),
    radial-gradient(900px 520px at 4% 8%, rgba(163,123,255,.13), transparent 60%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-deep) 100%);
}
.aurora__blob {
  position: absolute; border-radius: 50%; filter: blur(90px); opacity: .34; will-change: transform;
}
.aurora__blob--a {
  width: 42vw; height: 42vw; min-width: 340px; min-height: 340px;
  background: radial-gradient(circle at 30% 30%, #4f7ffb, transparent 68%);
  top: -12vw; right: -8vw; animation: drift-a 28s var(--ease) infinite alternate;
}
.aurora__blob--b {
  width: 34vw; height: 34vw; min-width: 280px; min-height: 280px;
  background: radial-gradient(circle at 60% 40%, #8b5cf6, transparent 68%);
  top: 46vh; left: -12vw; animation: drift-b 34s var(--ease) infinite alternate;
}
@keyframes drift-a { to { transform: translate3d(-5vw, 6vh, 0) scale(1.1); } }
@keyframes drift-b { to { transform: translate3d(7vw, -5vh, 0) scale(1.08); } }
.aurora__grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(to right, rgba(255,255,255,.04) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255,255,255,.04) 1px, transparent 1px);
  background-size: 68px 68px;
  mask-image: radial-gradient(ellipse 120% 70% at 50% 0%, #000 5%, transparent 72%);
}
[data-theme="light"] .aurora__blob { opacity: .24; }
[data-theme="light"] .aurora__grid {
  background-image:
    linear-gradient(to right, rgba(16,24,56,.05) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(16,24,56,.05) 1px, transparent 1px);
}

/* 5. Glass surfaces & buttons ---------------------------------------------- */

.glass {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(var(--blur)) saturate(160%);
  -webkit-backdrop-filter: blur(var(--blur)) saturate(160%);
  box-shadow: var(--shadow-md);
}
.glass::before {
  content: "";
  position: absolute; inset: 0; border-radius: inherit; padding: 1px;
  background: linear-gradient(160deg, rgba(255,255,255,.26), rgba(255,255,255,0) 42%);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor; mask-composite: exclude;
  pointer-events: none;
}
[data-theme="light"] .glass::before {
  background: linear-gradient(160deg, rgba(255,255,255,.95), rgba(255,255,255,0) 46%);
}

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .5rem;
  padding: .72rem 1.25rem; border: 1px solid transparent; border-radius: 999px;
  font-size: .92rem; font-weight: 560; letter-spacing: -0.01em; cursor: pointer; white-space: nowrap;
  transition: transform .2s var(--ease-out), box-shadow .2s var(--ease-out), background-color .2s var(--ease), border-color .2s var(--ease);
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }
.btn--primary {
  background: var(--gradient); color: #04070f; font-weight: 620;
  box-shadow: 0 10px 28px -12px rgba(110,168,255,.7);
}
[data-theme="light"] .btn--primary { color: #fff; }
.btn--ghost {
  background: var(--surface); border-color: var(--border); color: var(--text);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
}
.btn--ghost:hover { border-color: var(--border-hi); background: var(--surface-hi); }
.btn--sm { padding: .5rem .95rem; font-size: .82rem; }
.btn--block { width: 100%; }
.btn:disabled { opacity: .5; cursor: not-allowed; transform: none; }

.icon-btn {
  display: inline-grid; place-items: center; width: 2.5rem; height: 2.5rem; border-radius: 999px;
  border: 1px solid var(--border); background: var(--surface); color: var(--text); cursor: pointer;
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  transition: border-color .2s var(--ease), background-color .2s var(--ease), transform .2s var(--ease-out);
}
.icon-btn:hover { border-color: var(--border-hi); background: var(--surface-hi); transform: translateY(-1px); }
.icon-btn .icon { width: 1.1rem; height: 1.1rem; }

#theme-toggle .icon { grid-area: 1/1; transition: opacity .3s var(--ease), transform .4s var(--ease-out); }
#theme-toggle .icon--sun  { opacity: 0; transform: rotate(-70deg) scale(.6); }
#theme-toggle .icon--moon { opacity: 1; transform: none; }
[data-theme="light"] #theme-toggle .icon--sun  { opacity: 1; transform: none; }
[data-theme="light"] #theme-toggle .icon--moon { opacity: 0; transform: rotate(70deg) scale(.6); }

.chip, .badge {
  display: inline-flex; align-items: center; gap: .35rem; padding: .2rem .62rem; border-radius: 999px;
  font-family: var(--mono); font-size: .715rem; font-weight: 600; letter-spacing: .02em;
  border: 1px solid var(--border); background: var(--surface-hi); color: var(--text-muted);
}
.chip--ok, .badge--ok   { color: var(--ok);     border-color: rgba(56,211,159,.35); background: rgba(56,211,159,.10); }
.chip--warn, .badge--warn { color: var(--warn); border-color: rgba(245,181,68,.35); background: rgba(245,181,68,.10); }
.chip--brand { color: var(--brand); border-color: rgba(110,168,255,.35); background: var(--brand-soft); }

/* 6. Site header ----------------------------------------------------------- */

.site-header {
  position: sticky; top: 0; z-index: 60; height: var(--header-h);
  display: flex; align-items: center;
  border-bottom: 1px solid transparent;
  transition: background-color .3s var(--ease), border-color .3s var(--ease);
}
.site-header.is-stuck {
  background: color-mix(in oklab, var(--bg) 74%, transparent);
  backdrop-filter: blur(16px) saturate(160%); -webkit-backdrop-filter: blur(16px) saturate(160%);
  border-bottom-color: var(--border);
}
.site-header__inner { display: flex; align-items: center; gap: 1rem; width: 100%; }

.brand { display: inline-flex; align-items: center; gap: .6rem; margin-right: .25rem; }
.brand__mark {
  width: 1.95rem; height: 1.95rem; display: grid; place-items: center; border-radius: 10px;
  color: var(--brand); background: var(--brand-soft); border: 1px solid var(--border); flex: none;
}
.brand__mark svg { width: 1.25rem; height: 1.25rem; }
.brand__text { font-weight: 640; letter-spacing: -0.03em; font-size: 1.01rem; white-space: nowrap; }
.brand__text span { color: var(--text-muted); font-weight: 500; }
.brand__tag {
  font-family: var(--mono); font-size: .62rem; font-weight: 700; letter-spacing: .1em;
  padding: .18rem .45rem; border-radius: 5px; color: var(--brand-2);
  background: rgba(163,123,255,.12); border: 1px solid rgba(163,123,255,.28);
  text-transform: uppercase; margin-left: .15rem;
}

.header-nav { display: flex; align-items: center; gap: .2rem; margin-right: auto; }
.header-nav a {
  padding: .5rem .8rem; border-radius: 999px; font-size: .875rem; color: var(--text-muted);
  transition: color .2s var(--ease), background-color .2s var(--ease);
}
.header-nav a:hover { color: var(--text); background: var(--surface-hi); }

.site-header__actions { display: flex; align-items: center; gap: .5rem; margin-left: auto; }
.nav-toggle { display: none; }
.nav-toggle__bars { display: grid; gap: 4px; }
.nav-toggle__bars i { display: block; width: 16px; height: 1.6px; background: currentColor; border-radius: 2px; transition: transform .3s var(--ease-out), opacity .2s var(--ease); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1) { transform: translateY(5.6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3) { transform: translateY(-5.6px) rotate(-45deg); }

.search-trigger {
  display: flex; align-items: center; gap: .55rem; padding: .5rem .65rem .5rem .85rem;
  border-radius: 999px; border: 1px solid var(--border); background: var(--surface); color: var(--text-faint);
  font-size: .82rem; cursor: pointer; min-width: 11rem;
  transition: border-color .2s var(--ease), background-color .2s var(--ease);
}
.search-trigger:hover { border-color: var(--border-hi); background: var(--surface-hi); }
.search-trigger .icon { color: var(--text-faint); }
.search-trigger__label { flex: 1; text-align: left; }
.search-trigger kbd { font-size: .68rem; padding: .05em .4em; }

/* 7. App shell -------------------------------------------------------------- */

.app-shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr) var(--toc-w);
  gap: clamp(1.25rem, 3vw, 2.75rem);
  max-width: 1440px;
  margin-inline: auto;
  padding-inline: var(--gutter);
  align-items: start;
}
.app-shell--no-toc { grid-template-columns: var(--sidebar-w) minmax(0, 1fr); }

/* 8. Sidebar navigation ------------------------------------------------------ */

.sidebar {
  position: sticky; top: calc(var(--header-h) + 1.25rem);
  max-height: calc(100vh - var(--header-h) - 2.5rem);
  overflow-y: auto;
  padding: 1.1rem .9rem 2rem;
  scrollbar-width: thin;
}
.sidebar::-webkit-scrollbar { width: 6px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border-hi); border-radius: 999px; }

.sidebar__progress { padding: .5rem .5rem 1.1rem; margin-bottom: .6rem; border-bottom: 1px solid var(--border); }
.sidebar__progress-label { display: flex; justify-content: space-between; font-size: .74rem; color: var(--text-faint); margin-bottom: .5rem; }
.sidebar__progress-label strong { color: var(--text); font-weight: 640; }

.sidebar__module { margin-bottom: .25rem; }
.sidebar__module-btn {
  width: 100%; display: flex; align-items: center; gap: .55rem; padding: .58rem .55rem;
  border-radius: var(--radius-sm); cursor: pointer; background: none; border: none; text-align: left;
  color: var(--text-muted); font-family: inherit; font-size: .84rem; font-weight: 590;
  transition: background-color .18s var(--ease), color .18s var(--ease);
}
.sidebar__module-btn:hover { background: var(--surface-hi); color: var(--text); }
.sidebar__module-index {
  display: inline-grid; place-items: center; width: 1.5rem; height: 1.5rem; flex: none; border-radius: 7px;
  font-family: var(--mono); font-size: .68rem; font-weight: 700;
  background: var(--surface-hi); color: var(--text-faint); border: 1px solid var(--border);
}
.sidebar__module.is-current .sidebar__module-index { color: var(--brand); border-color: rgba(110,168,255,.4); background: var(--brand-soft); }
.sidebar__module-title { flex: 1; }
.sidebar__module-chevron { color: var(--text-faint); transition: transform .22s var(--ease-out); flex: none; }
.sidebar__module.is-open .sidebar__module-chevron { transform: rotate(90deg); }

.sidebar__lessons {
  display: grid; gap: .1rem; overflow: hidden; max-height: 0;
  transition: max-height .3s var(--ease-out);
  padding-left: 2.05rem; border-left: 1px solid var(--border); margin-left: 1.2rem;
}
.sidebar__module.is-open .sidebar__lessons { max-height: 40rem; }

.sidebar__lesson {
  display: flex; align-items: center; gap: .5rem; padding: .42rem .55rem; border-radius: 8px;
  color: var(--text-faint); font-size: .81rem; line-height: 1.35;
  transition: background-color .16s var(--ease), color .16s var(--ease);
}
.sidebar__lesson:hover { color: var(--text); background: var(--surface-hi); }
.sidebar__lesson.is-active { color: var(--brand); background: var(--brand-soft); font-weight: 600; }
.sidebar__lesson-dot {
  width: .95rem; height: .95rem; flex: none; border-radius: 50%; border: 1.5px solid var(--border-hi);
  display: grid; place-items: center; color: transparent;
}
.sidebar__lesson.is-done .sidebar__lesson-dot { background: var(--ok); border-color: var(--ok); color: #04070f; }
.sidebar__lesson.is-done .sidebar__lesson-dot svg { width: .6rem; height: .6rem; }
.sidebar__lesson.is-active .sidebar__lesson-dot { border-color: var(--brand); }

.sidebar__footer { padding: 1rem .55rem 0; margin-top: .75rem; border-top: 1px solid var(--border); }
.sidebar__reset {
  font-size: .74rem; color: var(--text-faint); background: none; border: none; cursor: pointer;
  padding: .3rem 0; font-family: inherit; text-decoration: underline; text-underline-offset: 3px;
}
.sidebar__reset:hover { color: var(--text-muted); }

/* 9. Table of contents -------------------------------------------------------- */

.toc {
  position: sticky; top: calc(var(--header-h) + 1.25rem);
  max-height: calc(100vh - var(--header-h) - 2.5rem);
  overflow-y: auto; padding: .25rem 0 2rem;
  font-size: .82rem;
}
.toc__title { font-size: .72rem; font-weight: 650; letter-spacing: .08em; text-transform: uppercase; color: var(--text-faint); margin-bottom: .8rem; }
.toc__list { display: grid; gap: .05rem; border-left: 1px solid var(--border); }
.toc__list a {
  display: block; padding: .32rem 0 .32rem .9rem; color: var(--text-faint); border-left: 2px solid transparent; margin-left: -1px;
  transition: color .16s var(--ease), border-color .16s var(--ease);
}
.toc__list a:hover { color: var(--text); }
.toc__list a.is-active { color: var(--brand); border-left-color: var(--brand); font-weight: 600; }
.toc__list .toc__h3 { padding-left: 1.7rem; font-size: .93em; }

/* 10. Breadcrumb & lesson pager ------------------------------------------------ */

.breadcrumb { display: flex; flex-wrap: wrap; align-items: center; gap: .4rem; font-size: .82rem; color: var(--text-faint); margin-bottom: 1.5rem; }
.breadcrumb a { color: var(--text-faint); transition: color .16s var(--ease); }
.breadcrumb a:hover { color: var(--brand); }
.breadcrumb__sep { color: var(--text-faint); opacity: .5; }
.breadcrumb__current { color: var(--text-muted); }

.lesson-pager { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top: 3rem; }
.lesson-pager__link {
  display: flex; flex-direction: column; gap: .3rem; padding: 1.1rem 1.25rem; border-radius: var(--radius);
  transition: transform .25s var(--ease-out), border-color .25s var(--ease);
}
.lesson-pager__link:hover { transform: translateY(-3px); border-color: var(--border-hi); }
.lesson-pager__link--next { text-align: right; align-items: flex-end; grid-column: 2; }
.lesson-pager__dir { display: flex; align-items: center; gap: .4rem; font-size: .72rem; letter-spacing: .07em; text-transform: uppercase; color: var(--text-faint); }
.lesson-pager__title { font-weight: 620; color: var(--text); font-size: .96rem; }
.lesson-pager__placeholder { grid-column: span 1; }

/* 11. Homepage ------------------------------------------------------------------ */

.home-hero { padding-block: clamp(2.75rem, 6vw, 5rem) clamp(2rem, 4vw, 3.5rem); }
.home-hero__inner { display: grid; grid-template-columns: minmax(0,1.05fr) minmax(0,.95fr); gap: clamp(2rem, 4vw, 3.5rem); align-items: center; }
.home-hero h1 { font-size: clamp(2.4rem, 5.2vw, 3.9rem); }
.home-hero__lede { margin-top: 1.25rem; max-width: 34rem; font-size: clamp(1rem, 1.3vw, 1.1rem); color: var(--text-muted); }
.home-hero__cta { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 2rem; }
.home-hero__facts { display: flex; flex-wrap: wrap; gap: .55rem 1.4rem; margin-top: 2.1rem; padding-top: 1.5rem; border-top: 1px solid var(--border); font-size: .86rem; color: var(--text-faint); }
.home-hero__facts li { display: inline-flex; align-items: center; gap: .5rem; }
.home-hero__facts .icon { color: var(--brand); }

.continue-card { padding: 1.35rem 1.4rem; display: flex; align-items: center; gap: 1.25rem; }
.continue-card__ring { flex: none; position: relative; width: 104px; height: 104px; }
.continue-card__ring svg { position: absolute; inset: 0; }
.continue-card__ring-label { position: absolute; inset: 0; display: grid; place-items: center; font-size: 1.05rem; font-weight: 700; font-family: var(--mono); }
.continue-card__body { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: .3rem; }
.continue-card__eyebrow { display: block; font-size: .72rem; text-transform: uppercase; letter-spacing: .08em; color: var(--brand-3); font-weight: 650; }
.continue-card__title { display: block; font-weight: 620; font-size: .98rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: var(--text); text-decoration: none; }
a.continue-card__title:hover { color: var(--brand); }
.continue-card__sub { display: block; font-size: .8rem; color: var(--text-faint); }

.section { padding-block: clamp(3rem, 6vw, 5.5rem); position: relative; }
.section--tint::before {
  content: ""; position: absolute; inset: 0; background: var(--gradient-soft); opacity: .5;
  mask-image: linear-gradient(180deg, transparent, #000 12%, #000 88%, transparent); pointer-events: none;
}
.section__head { max-width: 42rem; margin-bottom: clamp(2rem, 4vw, 3rem); }
.section__head h2 { margin-top: 0; }
.section__sub { margin-top: .9rem; color: var(--text-muted); font-size: 1.02rem; }

/* Roadmap */
.roadmap { display: grid; gap: .1rem; counter-reset: step; }
.roadmap__item {
  position: relative; display: grid; grid-template-columns: 3.5rem minmax(0,1fr); gap: 1.25rem;
  padding-block: 1.1rem;
}
.roadmap__rail { display: flex; flex-direction: column; align-items: center; }
.roadmap__num {
  width: 3rem; height: 3rem; border-radius: 14px; display: grid; place-items: center; flex: none;
  font-family: var(--mono); font-weight: 700; font-size: 1rem;
  background: var(--surface-hi); border: 1px solid var(--border); color: var(--text-muted);
}
.roadmap__item.is-milestone .roadmap__num { color: var(--brand); border-color: rgba(110,168,255,.4); background: var(--brand-soft); }
.roadmap__line { flex: 1; width: 2px; background: linear-gradient(var(--border-hi), var(--border)); margin-block: .4rem; min-height: 1.5rem; }
.roadmap__item:last-child .roadmap__line { display: none; }
.roadmap__card { padding: 1.15rem 1.35rem; }
.roadmap__card h3 { margin: 0 0 .4rem; font-size: 1.05rem; }
.roadmap__card p { margin: 0; color: var(--text-muted); font-size: .9rem; }
.roadmap__tags { display: flex; flex-wrap: wrap; gap: .4rem; margin-top: .8rem; }

/* Module grid (homepage) */
.module-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 20rem), 1fr)); gap: 1.1rem; }
.module-card {
  display: flex; flex-direction: column; padding: 1.5rem 1.5rem 1.35rem; overflow: hidden;
  transition: transform .3s var(--ease-out), border-color .3s var(--ease), box-shadow .3s var(--ease);
}
.module-card:hover { transform: translateY(-4px); border-color: var(--border-hi); box-shadow: var(--shadow-lg); }
.module-card__top { display: flex; align-items: center; justify-content: space-between; margin-bottom: .9rem; }
.module-card__top .icon { width: 2.1rem; height: 2.1rem; padding: .5rem; border-radius: 10px; background: var(--brand-soft); color: var(--brand); box-sizing: border-box; }
.module-card__index { font-family: var(--mono); font-size: .78rem; font-weight: 700; color: var(--text-faint); }
.module-card__count { font-size: .72rem; color: var(--text-faint); }
.module-card h3 { margin: 0 0 .5rem; font-size: 1.08rem; }
.module-card p { margin: 0; color: var(--text-muted); font-size: .875rem; flex: 1; }
.module-card__progress { margin-top: 1.1rem; }
.module-card__bar { height: 4px; border-radius: 999px; background: var(--surface-hi); overflow: hidden; margin-top: .5rem; }
.module-card__bar span { display: block; height: 100%; background: var(--gradient); border-radius: inherit; transition: width .5s var(--ease-out); }
.module-card__meta { display: flex; justify-content: space-between; font-size: .72rem; color: var(--text-faint); }
.module-card__link { position: absolute; inset: 0; }

/* Tech stack strip (homepage) */
.tech-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 12.5rem), 1fr)); gap: .8rem; }

/* 12. Progress ------------------------------------------------------------------- */

.progress-ring { transform: rotate(-90deg); }
.progress-ring__bg { fill: none; stroke: var(--border); }
.progress-ring__bar { fill: none; stroke: url(#ring-gradient); stroke-linecap: round; transition: stroke-dashoffset .6s var(--ease-out); }
.progress-ring__label { transform: rotate(90deg); font-family: var(--mono); font-weight: 700; }

.progress-bar { height: 6px; border-radius: 999px; background: var(--surface-hi); overflow: hidden; }
.progress-bar span { display: block; height: 100%; background: var(--gradient); border-radius: inherit; transition: width .6s var(--ease-out); }

/* 13. Lesson content --------------------------------------------------------------- */

.lesson { min-width: 0; padding-block: 1.75rem clamp(3rem, 6vw, 4.5rem); max-width: var(--content-max); }
.lesson__header { margin-bottom: 2.25rem; }
.lesson__header .eyebrow { margin-bottom: .6rem; }
.lesson__summary { margin-top: .9rem; font-size: 1.05rem; color: var(--text-muted); max-width: 40rem; }
.lesson__meta { display: flex; flex-wrap: wrap; gap: .5rem; margin-top: 1.1rem; }

.lesson h2 { scroll-margin-top: calc(var(--header-h) + 1.5rem); padding-top: .25rem; border-top: 1px solid var(--border); margin-top: 2.75rem; padding-top: 1rem; }
.lesson h2:first-of-type { border-top: none; margin-top: 0; padding-top: 0; }
.lesson h3 { scroll-margin-top: calc(var(--header-h) + 1.5rem); }
.lesson p, .lesson li { color: var(--text-muted); }
.lesson strong { color: var(--text); }
.lesson a:not(.btn) { color: var(--brand); text-underline-offset: 3px; text-decoration: underline; text-decoration-color: rgba(110,168,255,.35); }
.lesson a:not(.btn):hover { text-decoration-color: var(--brand); }
.lesson ul:not([class]), .lesson ol:not([class]) { margin: 0 0 1.1rem; padding-left: 1.3rem; }
.lesson ul:not([class]) > li { list-style: disc; margin-bottom: .4rem; }
.lesson ol:not([class]) > li { list-style: decimal; margin-bottom: .4rem; }
.lesson table { width: 100%; border-collapse: collapse; margin: 1rem 0 1.5rem; font-size: .9rem; }
.lesson th, .lesson td { text-align: left; padding: .6rem .8rem; border-bottom: 1px solid var(--border); vertical-align: top; }
.lesson th { color: var(--text-faint); font-size: .74rem; text-transform: uppercase; letter-spacing: .06em; font-weight: 650; }
.lesson td code { white-space: normal; }
.lesson figure { margin: 1.5rem 0; }
.lesson figcaption { margin-top: .7rem; font-size: .82rem; color: var(--text-faint); text-align: center; }

.section-block { margin-block: 2.5rem; }

/* Numbered steps */
.steps { counter-reset: stepnum; display: grid; gap: 1.5rem; margin: 1.5rem 0 2rem; }
.step { position: relative; padding-left: 3.1rem; }
.step::before {
  counter-increment: stepnum; content: counter(stepnum);
  position: absolute; left: 0; top: .1rem; width: 2.2rem; height: 2.2rem; border-radius: 10px;
  display: grid; place-items: center; font-family: var(--mono); font-weight: 700; font-size: .95rem;
  background: var(--brand-soft); color: var(--brand); border: 1px solid rgba(110,168,255,.3);
}
.step h4 { margin: 0 0 .5rem; font-size: 1.02rem; }
.step > p:last-child { margin-bottom: 0; }

/* Callouts */
.callout {
  position: relative; display: grid; grid-template-columns: auto minmax(0,1fr); gap: .9rem;
  padding: 1.15rem 1.3rem; border-radius: var(--radius); margin: 1.75rem 0;
  border: 1px solid var(--border); background: var(--surface-hi);
}
.callout__icon {
  width: 2rem; height: 2rem; border-radius: 9px; display: grid; place-items: center; flex: none;
}
.callout__icon .icon { width: 1.1rem; height: 1.1rem; }
.callout__body p:last-child { margin-bottom: 0; }
.callout__title { font-weight: 650; font-size: .82rem; letter-spacing: .04em; text-transform: uppercase; margin-bottom: .35rem; display: block; }

.callout--objectives { border-color: rgba(110,168,255,.28); background: var(--brand-soft); }
.callout--objectives .callout__icon { background: rgba(110,168,255,.18); color: var(--brand); }
.callout--objectives ul { margin: 0; padding: 0; list-style: none; }
.callout--objectives ul li::marker { content: none; }
/* A plain block layout with an absolutely-positioned bullet — NOT display:flex.
   Flex treats every inline child (each <code> in this list's mixed text-and-code
   content) as its own flex item, which visually shreds a sentence into boxes. */
.callout--objectives li { list-style: none; position: relative; padding-left: 1.15rem; margin-bottom: .5rem; color: var(--text); font-size: .93rem; line-height: 1.55; }
.callout--objectives li::before { content: ""; position: absolute; left: 0; top: .55rem; width: .4rem; height: .4rem; border-radius: 50%; background: var(--brand); }
.callout--objectives li:last-child { margin-bottom: 0; }

.callout--why { border-color: rgba(163,123,255,.28); background: rgba(163,123,255,.08); }
.callout--why .callout__icon { background: rgba(163,123,255,.18); color: var(--brand-2); }

.callout--hood { border-color: var(--border-hi); background: var(--surface-hi); border-style: dashed; }
.callout--hood .callout__icon { background: var(--surface-hi); color: var(--text-muted); }

.callout--tip { border-color: rgba(63,224,197,.28); background: rgba(63,224,197,.08); }
.callout--tip .callout__icon { background: rgba(63,224,197,.16); color: var(--brand-3); }

.callout--warning { border-color: rgba(245,181,68,.35); background: rgba(245,181,68,.09); }
.callout--warning .callout__icon { background: rgba(245,181,68,.18); color: var(--warn); }

.callout--security { border-color: rgba(255,107,129,.32); background: rgba(255,107,129,.08); }
.callout--security .callout__icon { background: rgba(255,107,129,.16); color: var(--danger); }

.callout--cost { border-color: rgba(245,181,68,.3); background: rgba(245,181,68,.06); border-style: dashed; }
.callout--cost .callout__icon { background: rgba(245,181,68,.16); color: var(--warn); }

.callout--real-world { border-color: var(--border-hi); background: var(--surface); }
.callout--real-world .callout__icon { background: var(--surface-hi); color: var(--brand); }

.callout--error { border-color: rgba(255,107,129,.28); background: var(--surface-hi); }
.callout--error .callout__icon { background: rgba(255,107,129,.14); color: var(--danger); }
.callout--error .error-fix { margin-top: .7rem; padding-top: .7rem; border-top: 1px dashed var(--border); }
.callout--error .error-fix strong { color: var(--ok); }

.callout--checkpoint { border-color: rgba(56,211,159,.32); background: rgba(56,211,159,.07); }
.callout--checkpoint .callout__icon { background: rgba(56,211,159,.16); color: var(--ok); }

.callout--exercise, .callout--challenge { border-color: rgba(110,168,255,.25); background: var(--surface); }
.callout--exercise .callout__icon { background: var(--brand-soft); color: var(--brand); }
.callout--challenge { border-style: dashed; border-color: rgba(163,123,255,.35); }
.callout--challenge .callout__icon { background: rgba(163,123,255,.16); color: var(--brand-2); }

.callout--recap { border-color: var(--border-hi); background: var(--surface-hi); }
.callout--recap .callout__icon { background: var(--surface); color: var(--text-muted); }

/* 14. Code, terminal & command blocks ------------------------------------------------ */

.code-block { margin: 1.5rem 0; border-radius: var(--radius); overflow: hidden; border: 1px solid var(--border); background: var(--surface-solid); box-shadow: var(--shadow-sm); }
.code-block__bar { display: flex; align-items: center; gap: .6rem; padding: .6rem .9rem; border-bottom: 1px solid var(--border); background: rgba(255,255,255,.02); }
[data-theme="light"] .code-block__bar { background: rgba(16,24,56,.025); }
.code-block__lang { font-family: var(--mono); font-size: .72rem; color: var(--text-faint); text-transform: uppercase; letter-spacing: .06em; }
.code-block__file { font-family: var(--mono); font-size: .78rem; color: var(--text-muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.code-block__spacer { flex: 1; }
.code-block pre {
  margin: 0; padding: 1.1rem 1.25rem; overflow-x: auto; font-size: .84rem; line-height: 1.65;
  color: var(--text-muted); -webkit-overflow-scrolling: touch;
}
.code-block code { background: none; padding: 0; white-space: pre; color: inherit; }
.code-block .tok-kw   { color: var(--brand-2); }
.code-block .tok-str  { color: var(--brand-3); }
.code-block .tok-com  { color: var(--text-faint); font-style: italic; }
.code-block .tok-fn   { color: var(--brand); }
.code-block .tok-num  { color: var(--warn); }
.code-block .tok-attr { color: var(--text); }
.code-block .tok-hl   { background: rgba(110,168,255,.12); display: inline-block; width: 100%; margin: 0 -1.25rem; padding: 0 1.25rem; }

.copy-btn {
  display: inline-flex; align-items: center; gap: .35rem; padding: .32rem .65rem; border-radius: 7px;
  border: 1px solid var(--border); background: var(--surface); color: var(--text-faint); cursor: pointer;
  font-size: .72rem; font-family: var(--font); transition: border-color .18s var(--ease), color .18s var(--ease);
}
.copy-btn:hover { border-color: var(--border-hi); color: var(--text); }
.copy-btn .icon { width: .9rem; height: .9rem; }
.copy-btn.is-copied { color: var(--ok); border-color: rgba(56,211,159,.4); }

.terminal { margin: 1.5rem 0; border-radius: var(--radius); overflow: hidden; border: 1px solid var(--border); background: var(--surface-solid); box-shadow: var(--shadow-sm); }
.terminal__bar { display: flex; align-items: center; gap: .5rem; padding: .65rem .9rem; border-bottom: 1px solid var(--border); background: rgba(255,255,255,.02); }
[data-theme="light"] .terminal__bar { background: rgba(16,24,56,.025); }
.terminal__dot { width: .58rem; height: .58rem; border-radius: 50%; }
.terminal__dot--r { background: #ff5f57; } .terminal__dot--a { background: #febc2e; } .terminal__dot--g { background: #28c840; }
.terminal__title { margin-left: .5rem; font-family: var(--mono); font-size: .72rem; color: var(--text-faint); }
.terminal__body { padding: 1.05rem 1.25rem; font-family: var(--mono); font-size: .84rem; line-height: 1.85; }
.terminal__line { display: flex; align-items: flex-start; gap: .55rem; }
.terminal__prompt { color: var(--brand-3); flex: none; user-select: none; }
.terminal__cmd { color: var(--text); flex: 1; word-break: break-word; }
.terminal__out { color: var(--text-faint); white-space: pre-wrap; margin: .35rem 0 .85rem 1.1rem; }
.terminal__cmd-row { display: flex; align-items: flex-start; justify-content: space-between; gap: .75rem; }
.terminal__cmd-row .copy-btn { flex: none; margin-top: -.1rem; }

/* 15. File tree ------------------------------------------------------------------------ */

.file-tree { margin: 1.5rem 0; padding: 1.1rem 1.3rem; border-radius: var(--radius); font-family: var(--mono); font-size: .84rem; line-height: 1.9; }
.file-tree__row { display: flex; align-items: center; gap: .55rem; color: var(--text-muted); white-space: pre; }
.file-tree__row .icon { color: var(--text-faint); flex: none; width: .95rem; height: .95rem; }
.file-tree__row--dir { color: var(--text); font-weight: 600; }
.file-tree__row--new .icon, .file-tree__row--new { color: var(--brand-3); }
.file-tree__row--new::after { content: "new"; margin-left: auto; font-size: .68rem; color: var(--brand-3); border: 1px solid rgba(63,224,197,.35); background: rgba(63,224,197,.1); padding: 0 .4em; border-radius: 5px; }

/* 16. Tabs & accordion -------------------------------------------------------------------- */

.tabs { margin: 1.5rem 0; }
.tabs__list { display: flex; gap: .3rem; border-bottom: 1px solid var(--border); flex-wrap: wrap; }
.tabs__tab { padding: .6rem 1rem; font-size: .86rem; color: var(--text-faint); background: none; border: none; cursor: pointer; font-family: inherit; border-bottom: 2px solid transparent; margin-bottom: -1px; transition: color .18s var(--ease), border-color .18s var(--ease); }
.tabs__tab:hover { color: var(--text); }
.tabs__tab.is-active { color: var(--brand); border-bottom-color: var(--brand); }
.tabs__panel { display: none; padding-top: 1.25rem; }
.tabs__panel.is-active { display: block; }
.tabs__panel > *:last-child { margin-bottom: 0; }

.accordion { margin: 1.5rem 0; border-radius: var(--radius); overflow: hidden; }
.accordion__item + .accordion__item { border-top: 1px solid var(--border); }
.accordion__trigger {
  width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 1rem;
  padding: 1rem 1.2rem; background: none; border: none; cursor: pointer; text-align: left;
  font-family: inherit; font-size: .93rem; font-weight: 590; color: var(--text);
}
.accordion__trigger .icon { color: var(--text-faint); transition: transform .25s var(--ease-out); flex: none; }
.accordion__item.is-open .accordion__trigger .icon { transform: rotate(45deg); }
.accordion__panel { max-height: 0; overflow: hidden; transition: max-height .3s var(--ease-out); }
.accordion__item.is-open .accordion__panel { max-height: 60rem; }
.accordion__panel-inner { padding: 0 1.2rem 1.15rem; color: var(--text-muted); font-size: .9rem; }
.accordion__panel-inner > *:last-child { margin-bottom: 0; }

/* 17. Checklist & quiz ---------------------------------------------------------------------- */

.checklist { display: grid; gap: .6rem; margin: 1.5rem 0; }
.checklist__item { display: flex; align-items: flex-start; gap: .7rem; padding: .7rem .9rem; border-radius: var(--radius-sm); background: var(--surface-hi); border: 1px solid var(--border); cursor: pointer; }
.checklist__box { width: 1.2rem; height: 1.2rem; border-radius: 6px; border: 1.5px solid var(--border-hi); flex: none; margin-top: .1rem; display: grid; place-items: center; transition: background-color .16s var(--ease), border-color .16s var(--ease); }
.checklist__item.is-checked .checklist__box { background: var(--ok); border-color: var(--ok); }
.checklist__box svg { width: .75rem; height: .75rem; color: #04070f; opacity: 0; transition: opacity .15s var(--ease); }
.checklist__item.is-checked .checklist__box svg { opacity: 1; }
.checklist__text { font-size: .91rem; color: var(--text-muted); }
.checklist__item.is-checked .checklist__text { color: var(--text-faint); text-decoration: line-through; text-decoration-color: var(--border-hi); }

.quiz { margin: 1.75rem 0; padding: 1.4rem 1.5rem; border-radius: var(--radius-lg); }
.quiz__q { font-weight: 620; font-size: .98rem; margin-bottom: 1rem; color: var(--text); }
.quiz__options { display: grid; gap: .55rem; }
.quiz__option {
  display: flex; align-items: center; gap: .7rem; padding: .7rem .95rem; border-radius: var(--radius-sm);
  border: 1px solid var(--border); background: var(--surface); cursor: pointer; font-size: .89rem; color: var(--text-muted);
  text-align: left; font-family: inherit; transition: border-color .16s var(--ease), background-color .16s var(--ease);
}
.quiz__option:hover:not(:disabled) { border-color: var(--border-hi); background: var(--surface-hi); }
.quiz__option-mark { width: 1.15rem; height: 1.15rem; border-radius: 50%; border: 1.5px solid var(--border-hi); flex: none; display: grid; place-items: center; }
.quiz__option.is-correct { border-color: rgba(56,211,159,.5); background: rgba(56,211,159,.1); color: var(--text); }
.quiz__option.is-correct .quiz__option-mark { background: var(--ok); border-color: var(--ok); }
.quiz__option.is-wrong { border-color: rgba(255,107,129,.5); background: rgba(255,107,129,.08); color: var(--text); }
.quiz__option.is-wrong .quiz__option-mark { background: var(--danger); border-color: var(--danger); }
.quiz__option:disabled { cursor: default; }
.quiz__feedback { margin-top: 1rem; padding-top: 1rem; border-top: 1px dashed var(--border); font-size: .87rem; color: var(--text-muted); display: none; }
.quiz__feedback.is-visible { display: block; }
.quiz__feedback strong { color: var(--text); }

/* 18. Git-history mapping -------------------------------------------------------------------- */

.git-map { margin: 1.75rem 0; padding: 1.2rem 1.35rem; border-radius: var(--radius); display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.git-map__icon { width: 2.2rem; height: 2.2rem; border-radius: 9px; display: grid; place-items: center; background: var(--surface-hi); color: var(--text-muted); flex: none; }
.git-map__body { flex: 1; min-width: 12rem; }
.git-map__label { font-size: .72rem; text-transform: uppercase; letter-spacing: .07em; color: var(--text-faint); font-weight: 650; margin-bottom: .3rem; }
.git-map__commit { font-family: var(--mono); font-size: .88rem; color: var(--text); }
.git-map__hash { font-family: var(--mono); color: var(--brand-3); }

/* 19. Service badges ----------------------------------------------------------------------- */

.service-badge {
  display: inline-flex; align-items: center; gap: .5rem; padding: .4rem .8rem .4rem .55rem; border-radius: 10px;
  border: 1px solid var(--border); background: var(--surface-hi); font-size: .82rem; font-weight: 600; color: var(--text);
}
.service-badge__icon { width: 1.55rem; height: 1.55rem; border-radius: 7px; display: grid; place-items: center; flex: none; }
.service-row { display: flex; flex-wrap: wrap; gap: .6rem; margin: 1.25rem 0; }

/* AWS-family palette per service, used for the badge icon background */
.svc-s3 .service-badge__icon         { background: rgba(63,166,90,.16); color: #5fb87d; }
.svc-cloudfront .service-badge__icon { background: rgba(139,92,246,.16); color: #a78bfa; }
.svc-iam .service-badge__icon        { background: rgba(245,181,68,.16); color: #f5b544; }
.svc-acm .service-badge__icon        { background: rgba(110,168,255,.16); color: #6ea8ff; }
.svc-route53 .service-badge__icon    { background: rgba(139,92,246,.16); color: #a78bfa; }
.svc-cloudwatch .service-badge__icon { background: rgba(255,107,129,.16); color: #ff8ea0; }
.svc-alb .service-badge__icon        { background: rgba(245,181,68,.16); color: #f5b544; }
.svc-ec2 .service-badge__icon        { background: rgba(245,181,68,.16); color: #f5b544; }
.svc-ecs .service-badge__icon        { background: rgba(245,181,68,.16); color: #f5b544; }
.svc-terraform .service-badge__icon  { background: rgba(110,90,255,.16); color: #8f7bff; }
.svc-git .service-badge__icon        { background: rgba(255,107,129,.16); color: #ff8ea0; }
.svc-github .service-badge__icon     { background: var(--surface); color: var(--text); }
.svc-actions .service-badge__icon    { background: rgba(63,224,197,.16); color: #3fe0c5; }

/* 20. Architecture diagrams ----------------------------------------------------------------- */

.diagram { padding: clamp(1.4rem, 3vw, 2rem); border-radius: var(--radius-lg); margin: 1.75rem 0; }
.diagram--flow { display: grid; gap: 0; }
.diagram--row { display: grid; grid-auto-flow: column; grid-auto-columns: 1fr; align-items: center; gap: 0; }

.dnode {
  display: grid; gap: .15rem; padding: 1rem 1.1rem; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--surface-hi); text-align: center; transition: border-color .3s var(--ease), transform .3s var(--ease-out);
  position: relative;
}
.dnode:hover { border-color: var(--border-hi); transform: translateY(-2px); }
.dnode__kind { font-size: .66rem; letter-spacing: .1em; text-transform: uppercase; color: var(--brand); font-weight: 650; }
.dnode strong { font-size: .96rem; letter-spacing: -0.02em; }
.dnode__meta { font-size: .71rem; color: var(--text-faint); }
.dnode--dashed { border-style: dashed; }
.dnode--accent { border-color: rgba(110,168,255,.35); background: var(--brand-soft); }
.dnode--future { border-color: rgba(245,181,68,.35); background: rgba(245,181,68,.07); border-style: dashed; }
.dnode--icon { width: 2.1rem; height: 2.1rem; border-radius: 8px; display: grid; place-items: center; margin: 0 auto .35rem; background: var(--surface); }

.dwire { position: relative; height: 2.75rem; display: grid; place-items: center; }
.dwire--v::before { content: ""; position: absolute; top: 0; bottom: 0; width: 1px; background: linear-gradient(180deg, var(--border-hi), var(--brand), var(--border-hi)); opacity: .55; }
.dwire--h { height: auto; padding-inline: .5rem; }
.dwire--h::before { content: ""; position: absolute; left: 0; right: 0; top: 50%; height: 1px; background: linear-gradient(90deg, var(--border-hi), var(--brand), var(--border-hi)); opacity: .55; }
.dwire__label { position: relative; z-index: 1; font-size: .66rem; padding: .12rem .5rem; border-radius: 999px; background: var(--surface-solid); border: 1px solid var(--border); color: var(--text-muted); white-space: nowrap; }
.dwire__packet { position: absolute; width: .36rem; height: .36rem; border-radius: 50%; background: var(--brand-3); box-shadow: 0 0 10px 1px var(--brand-3); }
.dwire--v .dwire__packet { top: 0; left: 50%; transform: translateX(-50%); animation: travel-v 2.6s var(--ease) infinite; }
.dwire--h .dwire__packet { top: 50%; left: 0; transform: translateY(-50%); animation: travel-h 2.6s var(--ease) infinite; }
@keyframes travel-v { 0% { top: 0; opacity: 0; } 15% { opacity: 1; } 85% { opacity: 1; } 100% { top: 100%; opacity: 0; } }
@keyframes travel-h { 0% { left: 0; opacity: 0; } 15% { opacity: 1; } 85% { opacity: 1; } 100% { left: 100%; opacity: 0; } }

.diagram__blocked {
  display: flex; align-items: center; gap: .6rem; margin-top: 1.1rem; padding: .7rem .9rem; border-radius: var(--radius-sm);
  border: 1px dashed rgba(255,107,129,.35); background: rgba(255,107,129,.07); font-size: .78rem; color: var(--text-muted);
}
.diagram__blocked .x { display: grid; place-items: center; width: 1.2rem; height: 1.2rem; flex: none; border-radius: 50%; background: rgba(255,107,129,.16); color: var(--danger); font-size: .68rem; font-weight: 700; }
.diagram__caption { margin-top: 1rem; text-align: center; font-size: .8rem; color: var(--text-faint); }

.dbranch { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.dbranch__stem { grid-column: 1 / -1; display: flex; justify-content: center; }

/* Sequence diagram (vertical, for OIDC) */
.dsequence { display: grid; gap: 0; }
.dseq-row { display: grid; grid-template-columns: 1fr; gap: .3rem; padding-block: .55rem; position: relative; }
.dseq-row__num { display: inline-grid; place-items: center; width: 1.5rem; height: 1.5rem; border-radius: 50%; background: var(--surface-hi); border: 1px solid var(--border); font-family: var(--mono); font-size: .7rem; font-weight: 700; color: var(--text-faint); margin-right: .55rem; }
.dseq-row__text { display: inline-flex; align-items: center; font-size: .87rem; color: var(--text-muted); }
.dseq-row__text strong { color: var(--text); }
.dseq-row + .dseq-row { border-top: 1px dashed var(--border); }

/* 21. Command palette (search) ----------------------------------------------------------------- */

.palette-overlay {
  position: fixed; inset: 0; z-index: 300; display: grid; place-items: flex-start center;
  padding-top: min(14vh, 6.5rem); background: rgba(4,6,14,.55); backdrop-filter: blur(3px);
  opacity: 0; visibility: hidden; transition: opacity .18s var(--ease), visibility .18s;
}
.palette-overlay.is-open { opacity: 1; visibility: visible; }
[data-theme="light"] .palette-overlay { background: rgba(16,24,56,.28); }

.palette {
  width: min(94vw, 38rem); max-height: 70vh; display: flex; flex-direction: column; overflow: hidden;
  border-radius: var(--radius-lg); transform: translateY(-10px); transition: transform .2s var(--ease-out);
}
.palette-overlay.is-open .palette { transform: translateY(0); }
.palette__input-row { display: flex; align-items: center; gap: .75rem; padding: .95rem 1.1rem; border-bottom: 1px solid var(--border); }
.palette__input-row .icon { color: var(--text-faint); flex: none; }
.palette__input { flex: 1; background: none; border: none; outline: none; color: var(--text); font-size: 1rem; font-family: inherit; }
.palette__input::placeholder { color: var(--text-faint); }
.palette__esc { font-size: .7rem; color: var(--text-faint); }
.palette__results { overflow-y: auto; padding: .5rem; }
.palette__group-label { padding: .5rem .7rem .3rem; font-size: .68rem; text-transform: uppercase; letter-spacing: .07em; color: var(--text-faint); font-weight: 650; }
.palette__item {
  display: flex; align-items: center; gap: .8rem; padding: .7rem .8rem; border-radius: var(--radius-sm); cursor: pointer;
  color: var(--text-muted);
}
.palette__item.is-selected { background: var(--brand-soft); color: var(--text); }
.palette__item-icon { width: 1.9rem; height: 1.9rem; border-radius: 8px; display: grid; place-items: center; background: var(--surface-hi); flex: none; color: var(--text-faint); }
.palette__item-body { flex: 1; min-width: 0; }
.palette__item-title { font-size: .89rem; color: var(--text); font-weight: 560; }
.palette__item-title mark { background: none; color: var(--brand); font-weight: 700; }
.palette__item-sub { font-size: .76rem; color: var(--text-faint); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.palette__empty { padding: 2.5rem 1rem; text-align: center; color: var(--text-faint); font-size: .89rem; }
.palette__footer { display: flex; gap: 1rem; padding: .6rem 1.1rem; border-top: 1px solid var(--border); font-size: .72rem; color: var(--text-faint); }
.palette__footer span { display: inline-flex; align-items: center; gap: .35rem; }

/* 22. Footer -------------------------------------------------------------------------------- */

.site-footer { border-top: 1px solid var(--border); padding-block: 2.25rem; margin-top: 3rem; }
.site-footer__inner { display: flex; flex-wrap: wrap; align-items: center; gap: 1.25rem 2rem; }
.site-footer__brand { display: flex; align-items: center; gap: .7rem; margin-right: auto; }
.site-footer__note { font-size: .82rem; color: var(--text-faint); }
.site-footer__links { display: flex; flex-wrap: wrap; gap: 1.1rem; font-size: .85rem; color: var(--text-muted); }
.site-footer__links a:hover { color: var(--text); }

/* 23. Responsive ------------------------------------------------------------------------------ */

@media (max-width: 1180px) {
  .app-shell, .app-shell--no-toc { grid-template-columns: var(--sidebar-w) minmax(0,1fr); }
  .toc { display: none; }
}

@media (max-width: 900px) {
  .hide-sm { display: none; }
  .nav-toggle { display: inline-grid; }
  .header-nav { display: none; }

  .app-shell { grid-template-columns: 1fr; padding-inline: 0; gap: 0; }
  .sidebar {
    position: fixed; top: 0; bottom: 0; left: 0; width: min(85vw, 20rem); z-index: 90;
    background: color-mix(in oklab, var(--bg) 92%, transparent);
    backdrop-filter: blur(20px) saturate(160%); -webkit-backdrop-filter: blur(20px) saturate(160%);
    border-right: 1px solid var(--border); max-height: 100vh;
    padding-top: calc(var(--header-h) + 1rem);
    transform: translateX(-100%); transition: transform .3s var(--ease-out);
  }
  .sidebar.is-open { transform: translateX(0); box-shadow: var(--shadow-lg); }
  .sidebar-backdrop {
    position: fixed; inset: 0; z-index: 85; background: rgba(4,6,14,.55); opacity: 0; visibility: hidden;
    transition: opacity .3s var(--ease), visibility .3s;
  }
  .sidebar-backdrop.is-open { opacity: 1; visibility: visible; }
  .lesson { padding-inline: var(--gutter); max-width: none; }

  .home-hero__inner { grid-template-columns: 1fr; }
  .roadmap__item { grid-template-columns: 2.75rem minmax(0,1fr); gap: .9rem; }
  .roadmap__num { width: 2.5rem; height: 2.5rem; font-size: .88rem; }
}

@media (max-width: 640px) {
  :root { --header-h: 3.5rem; }
  .lesson-pager { grid-template-columns: 1fr; }
  .lesson-pager__link--next { grid-column: 1; text-align: left; align-items: flex-start; }
  .search-trigger .search-trigger__label, .search-trigger kbd { display: none; }
  .search-trigger { min-width: 0; padding: .5rem; }
  .callout { grid-template-columns: 1fr; }
  .callout__icon { display: none; }
  .continue-card { flex-direction: column; align-items: flex-start; text-align: left; }
}

/* 24. Reduced motion & print -------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .001ms !important; animation-iteration-count: 1 !important; transition-duration: .001ms !important; }
  .reveal { opacity: 1 !important; transform: none !important; }
}

.reveal { opacity: 0; transform: translateY(16px); transition: opacity .6s var(--ease-out), transform .6s var(--ease-out); transition-delay: var(--reveal-delay, 0ms); }
.reveal.is-visible { opacity: 1; transform: none; }

@media print {
  .aurora, .site-header, .sidebar, .toc, .lesson-pager, .palette-overlay, #site-footer { display: none; }
  body { background: #fff; color: #000; }
  .app-shell { grid-template-columns: 1fr; }
  .glass { border: 1px solid #ccc; box-shadow: none; backdrop-filter: none; }
}