/* ==================================================================== */
/*  ShikshaOS Showcase — main stylesheet                                 */
/*  Tokens, base, atmosphere and motion are copied verbatim from         */
/*  design-language.html (§1–§4). Components reference tokens only.      */
/* ==================================================================== */

/* ==================================================================== */
/*  1. DESIGN TOKENS                                                     */
/* ==================================================================== */
:root {
  color-scheme: dark;

  /* — Surfaces (darkest → lightest) — */
  --canvas: #0a0b0d;        /* page background, recessed inputs */
  --surface: #131419;       /* cards, panels, header */
  --surface-2: #1b1c22;     /* code blocks, image wells, insets */

  /* — Lines / borders — */
  --line: rgba(255, 255, 255, 0.08);          /* default hairline */
  --line-strong: rgba(255, 255, 255, 0.16);   /* dividers, ghost buttons, hover */

  /* — Ink (text) — */
  --ink: #f4f4f5;           /* headings, primary text, button labels */
  --ink-muted: #9b9da6;     /* body copy, descriptions */
  --ink-faint: #7a7c86;     /* captions, mono labels, disabled — 4.7:1 on canvas (AA) */

  /* — Accent (the one spark) — */
  --accent: #ff5d2e;        /* CTAs, links, sparks, the card square */
  --accent-soft: #ff8b66;   /* primary-button hover (lighter in dark) */

  /* — Atmosphere — */
  --grid-line: rgba(255, 255, 255, 0.035);
  --grain-opacity: 0.35;
  --grain-blend: overlay;

  /* — Misc surfaces — */
  --skeleton: rgba(255, 255, 255, 0.055);
  --scrollbar-thumb: #2c2d34;
  --scrollbar-thumb-hover: #3c3d45;

  /* — Type families — */
  --font-display: "Bricolage Grotesque", "Geist", ui-sans-serif, sans-serif;
  --font-sans: "Geist", ui-sans-serif, system-ui, sans-serif;
  --font-mono: "Geist Mono", ui-monospace, monospace;

  /* — Motion (non-themed; constant across modes) — */
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1); /* the house easing */
  --dur-fast: 0.2s;     /* hovers, color/border transitions */
  --dur-mid: 0.3s;      /* arrow nudges, theme cross-fade */
  --dur-reveal: 0.8s;   /* scroll-in reveal */

  /* — Radii (non-themed) — */
  --r-sm: 6px;     /* nav chips, logo tile, icon buttons (square) */
  --r-md: 8px;     /* inputs, small wells */
  --r-lg: 12px;    /* compact cards, code blocks */
  --r-xl: 16px;    /* panels, large cards, dialog */
  --r-pill: 999px; /* buttons, pills, tags, round icon buttons */
}

[data-theme="light"] {
  color-scheme: light;
  --canvas: #f4f3ef;        /* warm cream, not white */
  --surface: #ffffff;
  --surface-2: #eceae3;
  --line: rgba(20, 21, 24, 0.1);
  --line-strong: rgba(20, 21, 24, 0.2);
  --ink: #16171a;
  --ink-muted: #565860;
  --ink-faint: #6b6d75;     /* 4.7:1 on cream (AA) */
  --accent: #c93c0d;        /* 4.8:1 on cream both ways — as text and as button fill */
  --accent-soft: #a83109;   /* darker on hover in light mode */
  --grid-line: rgba(20, 21, 24, 0.055);
  --grain-opacity: 0.22;
  --grain-blend: multiply;
  --skeleton: rgba(20, 21, 24, 0.06);
  --scrollbar-thumb: #cdccc4;
  --scrollbar-thumb-hover: #b6b4aa;
}

/* ==================================================================== */
/*  2. BASE                                                              */
/* ==================================================================== */
* { box-sizing: border-box; border-color: var(--line); }
[hidden] { display: none !important; } /* .btn's display would otherwise win */
html { scroll-behavior: smooth; background-color: var(--canvas); overflow-x: clip; }
body {
  margin: 0; background: transparent; color: var(--ink);
  font-family: var(--font-sans); -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility; line-height: 1.6;
}
::selection { background: var(--accent); color: var(--canvas); }
a { color: inherit; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: var(--canvas); }
::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); border-radius: 999px; border: 2px solid var(--canvas); }
::-webkit-scrollbar-thumb:hover { background: var(--scrollbar-thumb-hover); }

/* ==================================================================== */
/*  3. ATMOSPHERE — fixed decorative layers                              */
/* ==================================================================== */
.bg-grid {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background-image:
    linear-gradient(to right, var(--grid-line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--grid-line) 1px, transparent 1px);
  background-size: 74px 74px;
  -webkit-mask-image: radial-gradient(ellipse 78% 56% at 50% -6%, #000 8%, transparent 80%);
  mask-image: radial-gradient(ellipse 78% 56% at 50% -6%, #000 8%, transparent 80%);
}
.bg-grain {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  opacity: var(--grain-opacity); mix-blend-mode: var(--grain-blend);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 220 220'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.82' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.5'/%3E%3C/svg%3E");
}

/* ==================================================================== */
/*  4. MOTION primitives                                                 */
/* ==================================================================== */
@keyframes fade-rise { from { opacity: 0; transform: translateY(24px); } to { opacity: 1; transform: translateY(0); } }
.rise { opacity: 0; animation: fade-rise 0.9s var(--ease-out-expo) both; }
@keyframes skeleton-pulse { 0%,100% { opacity: 1; } 50% { opacity: 0.5; } }
.skeleton { background-color: var(--skeleton); animation: skeleton-pulse 2.6s ease-in-out infinite; border-radius: var(--r-md); }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .rise { animation: none; opacity: 1; }
  .skeleton { animation: none; }
  /* Catch-all: every hover nudge, rotate and cross-fade lands on its end state. */
  *, *::before, *::after {
    animation-duration: 0.01ms !important; animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* ==================================================================== */
/*  5. PAGE CHROME — header, nav, footer                                 */
/* ==================================================================== */
.skip { position: absolute; left: 0.75rem; top: -3rem; z-index: 60; border-radius: var(--r-pill); background: var(--accent); color: var(--canvas); padding: 0.625rem 1rem; font-size: 0.875rem; text-decoration: none; transition: top var(--dur-fast) var(--ease-out-expo); }
.skip:focus-visible { top: 0.75rem; }

.wrap { max-width: 72rem; margin: 0 auto; padding: 0 1.5rem; }
@media (min-width: 768px) { .wrap { padding: 0 2.5rem; } }

/* Sticky also makes this the containing block for .mobile-nav, so the open panel
   overlays the page instead of growing the header and shoving content down. */
.site-header { position: sticky; top: 0; z-index: 50; backdrop-filter: blur(16px); background: color-mix(in srgb, var(--canvas) 85%, transparent); border-bottom: 1px solid var(--line); }
.site-header-inner { max-width: 72rem; margin: 0 auto; padding: 0 1.5rem; height: 64px; display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
@media (min-width: 768px) { .site-header-inner { padding: 0 2.5rem; } }

.brand-lockup { display: flex; align-items: center; gap: 0.625rem; text-decoration: none; }
.logo-tile { display: grid; place-items: center; height: 32px; width: 32px; border-radius: var(--r-sm); background: var(--accent); font-family: var(--font-display); font-weight: 800; font-size: 14px; color: var(--canvas); transition: transform var(--dur-mid) var(--ease-out-expo); }
.brand-lockup:hover .logo-tile { transform: rotate(-10deg); }
.brand-name { font-family: var(--font-display); font-weight: 700; font-size: 15px; letter-spacing: -0.01em; }
.brand-sub { font-size: 11px; color: var(--ink-faint); margin-top: 1px; }

.nav { display: none; align-items: center; gap: 0.25rem; }
/* 860, not 768: below this the six links + brand + toggle overflow the header row. */
@media (min-width: 860px) { .nav { display: flex; } }
.navlink { border-radius: var(--r-sm); padding: 0.5rem 0.75rem; text-decoration: none; font-family: var(--font-mono); font-size: 12px; text-transform: uppercase; letter-spacing: 0.14em; color: var(--ink-muted); transition: color var(--dur-fast); }
.navlink:hover { color: var(--ink); }
.navlink.active { color: var(--accent); }

.header-actions { display: flex; align-items: center; gap: 0.5rem; }

.icon-btn { display: grid; place-items: center; height: 40px; width: 40px; border-radius: var(--r-pill); border: 1px solid var(--line); background: transparent; color: var(--ink-muted); cursor: pointer; transition: border-color var(--dur-fast), color var(--dur-fast); }
.icon-btn:hover { border-color: var(--line-strong); color: var(--ink); }
.theme-icon-moon { display: none; }
[data-theme="light"] .theme-icon-sun { display: none; }
[data-theme="light"] .theme-icon-moon { display: inline; }

/* — Mobile nav: hamburger + drop-down panel, the < 860px counterpart of .nav — */
.nav-icon-close { display: none; }
.site-header[data-nav-open] .nav-toggle { border-color: var(--line-strong); color: var(--ink); }
.site-header[data-nav-open] .nav-icon-bars { display: none; }
.site-header[data-nav-open] .nav-icon-close { display: inline; }

.mobile-nav {
  position: absolute; top: 100%; left: 0; right: 0;
  display: grid; gap: 0.125rem;
  padding: 0.5rem 1.5rem 1rem;
  background: color-mix(in srgb, var(--canvas) 94%, transparent);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--line);
  /* visibility keeps the closed panel out of the tab order and the a11y tree;
     it flips instantly on open and waits out the fade on close. */
  opacity: 0; transform: translateY(-0.5rem); visibility: hidden;
  transition: opacity var(--dur-fast) var(--ease-out-expo),
              transform var(--dur-fast) var(--ease-out-expo),
              visibility 0s linear var(--dur-fast);
}
.site-header[data-nav-open] .mobile-nav {
  opacity: 1; transform: none; visibility: visible;
  transition: opacity var(--dur-fast) var(--ease-out-expo),
              transform var(--dur-fast) var(--ease-out-expo),
              visibility 0s;
}
@media (min-width: 768px) { .mobile-nav { padding: 0.5rem 2.5rem 1rem; } }
/* Same 860px hand-off as .nav — above it the inline links take over. */
@media (min-width: 860px) { .nav-toggle, .mobile-nav { display: none; } }

.m-navlink { display: flex; align-items: center; min-height: 44px; border-radius: var(--r-sm); padding: 0 0.75rem; text-decoration: none; font-family: var(--font-mono); font-size: 12px; text-transform: uppercase; letter-spacing: 0.14em; color: var(--ink-muted); transition: color var(--dur-fast), background-color var(--dur-fast); }
.m-navlink:hover, .m-navlink:focus-visible { color: var(--ink); background: var(--surface); }
.m-navlink.active { color: var(--accent); }

/* ==================================================================== */
/*  6. SECTION ANATOMY + COMPONENTS  (verbatim from design-language §6)  */
/* ==================================================================== */
section.block { padding: 4.5rem 0; border-top: 1px solid var(--line); scroll-margin-top: 84px; }
section.block:first-of-type { border-top: 0; }

.eyebrow { display: flex; align-items: center; gap: 0.75rem; font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.2em; color: var(--ink-faint); margin: 0 0 1.5rem; }
.eyebrow .idx { color: var(--accent); }
.eyebrow .rule { height: 1px; width: 40px; background: var(--line-strong); }

h1.display { font-family: var(--font-display); font-weight: 800; letter-spacing: -0.02em; line-height: 1.04; font-size: clamp(2.5rem, 6vw, 3.75rem); margin: 0; }
h2.display { font-family: var(--font-display); font-weight: 700; letter-spacing: -0.02em; line-height: 1.08; font-size: clamp(1.875rem, 4vw, 3rem); margin: 0 0 0.75rem; }
.lede { color: var(--ink-muted); font-size: 1.0625rem; max-width: 44rem; margin: 0 0 1.5rem; }
p.body { color: var(--ink-muted); max-width: 44rem; }
.faint { color: var(--ink-faint); }

.grid { display: grid; gap: 1rem; grid-template-columns: 1fr; }
@media (min-width: 640px) { .cols-2, .cols-3, .cols-4 { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1024px) { .cols-3 { grid-template-columns: repeat(3, 1fr); } .cols-4 { grid-template-columns: repeat(4, 1fr); } }

.btn { display: inline-flex; align-items: center; gap: 0.5rem; border-radius: var(--r-pill); padding: 0.875rem 1.5rem; font-size: 0.875rem; font-weight: 500; text-decoration: none; cursor: pointer; border: 1px solid transparent; transition: background-color var(--dur-fast), border-color var(--dur-fast), color var(--dur-fast); font-family: inherit; }
.btn-primary { background: var(--accent); color: var(--canvas); }
.btn-primary:hover { background: var(--accent-soft); }
.btn-ghost { border-color: var(--line-strong); color: var(--ink); background: transparent; }
.btn-ghost:hover { border-color: var(--ink); }
.btn .arw { display: inline-block; transition: transform var(--dur-mid) var(--ease-out-expo); }
.btn:hover .arw { transform: translateY(3px); }
.btn:hover .arw-out { transform: translate(3px, -3px); } /* outbound ↗ leans away, not down */

.pill { display: inline-block; border-radius: var(--r-pill); background: var(--accent); color: var(--canvas); padding: 0.5rem 1rem; font-size: 0.875rem; font-weight: 500; }
.tag { display: inline-flex; align-items: center; gap: 0.5rem; border-radius: var(--r-pill); border: 1px solid var(--line); background: var(--surface); padding: 0.25rem 0.75rem; font-family: var(--font-mono); font-size: 10px; text-transform: uppercase; letter-spacing: 0.18em; color: var(--ink-faint); }
.dot { height: 6px; width: 6px; border-radius: var(--r-pill); background: var(--accent); display: inline-block; flex: none; }

.card-lg { position: relative; display: flex; flex-direction: column; border-radius: var(--r-xl); border: 1px solid var(--line); background: var(--surface); padding: 1.5rem; transition: border-color var(--dur-fast); text-decoration: none; }
.card-lg:hover { border-color: var(--line-strong); }
.card-lg.dashed { border-style: dashed; border-color: var(--line-strong); }
.card-lg.dashed:hover { border-color: var(--accent); }
.well { display: grid; place-items: center; aspect-ratio: 16/10; width: 100%; overflow: hidden; border-radius: var(--r-md); border: 1px solid var(--line); background: var(--surface-2); transition: border-color var(--dur-fast); color: var(--ink-faint); }
.card-lg:hover .well { border-color: var(--line-strong); }
.card-lg .name { margin: 1.25rem 0 0; font-family: var(--font-display); font-weight: 600; font-size: 1.125rem; color: var(--ink); }
.card-lg .cat { margin-top: 0.25rem; font-family: var(--font-mono); font-size: 10px; text-transform: uppercase; letter-spacing: 0.14em; color: var(--ink-faint); }

.ico { color: var(--ink-faint); }
.well .ico { width: 62%; max-width: 260px; height: auto; }
.ico .accent { color: var(--accent); }

.impact { list-style: none; padding: 0; margin: 1rem 0 0; display: flex; flex-direction: column; gap: 0.5rem; }
.impact li { display: flex; gap: 0.625rem; font-size: 0.875rem; color: var(--ink-muted); }
.impact li::before { content: ""; flex: none; margin-top: 8px; height: 4px; width: 4px; border-radius: var(--r-pill); background: var(--accent); }

/* ==================================================================== */
/*  7. PAGE-SPECIFIC — hero + reveal                                     */
/* ==================================================================== */
.hero { position: relative; padding: 5rem 0 4.5rem; }
.hero-glow { position: absolute; top: -80px; right: 0; height: 420px; width: 420px; border-radius: var(--r-pill); background: color-mix(in srgb, var(--accent) 11%, transparent); filter: blur(90px); pointer-events: none; z-index: -1; }
/* The glow may only bleed past the hero once the centred wrap has margin to
   absorb it — that needs ~1192px of viewport, so 1280 leaves room for a
   scrollbar. Any narrower and it widens the document and the page pans
   sideways; html's overflow-x:clip doesn't save us, iOS Safari ignores clip
   propagation from the root. */
@media (min-width: 1280px) { .hero-glow { right: -60px; } }
.hero h1.display { margin-top: 1.5rem; max-width: 16ch; }
.hero h1 .spark { color: var(--accent); }
.hero .lede { margin-top: 1.5rem; }
.cta-row { display: flex; flex-wrap: wrap; gap: 0.75rem; align-items: center; margin-top: 2rem; }
.tag-row { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 2.5rem; }

/* Hide reveal targets only when JS is running (script adds .has-reveal). */
.has-reveal [data-reveal] > * { opacity: 0; }
@media (prefers-reduced-motion: reduce) { .has-reveal [data-reveal] > * { opacity: 1; } }

/* ==================================================================== */
/*  8. PROOF — mock demo, steps, stat row                                */
/* ==================================================================== */
.panel { border-radius: var(--r-xl); border: 1px solid var(--line); background: var(--surface); padding: 1.5rem; }
.card { border-radius: var(--r-lg); border: 1px solid var(--line); background: var(--surface); padding: 1.25rem; transition: border-color var(--dur-fast); }
.card:hover { border-color: var(--line-strong); }
.field-label { display: block; font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.16em; color: var(--ink-faint); margin-bottom: 0.5rem; }
.meta-key { margin: 0; font-family: var(--font-mono); font-size: 11px; font-weight: 400; text-transform: uppercase; letter-spacing: 0.18em; color: var(--accent); }
.meta-val { margin-top: 0.5rem; font-size: 0.875rem; color: var(--ink-muted); }
.btn-sm { padding: 0.5rem 1rem; font-family: var(--font-mono); font-size: 12px; text-transform: uppercase; letter-spacing: 0.14em; }
.vh { position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }

/* — Mock demo theater — */
.chip-row { display: flex; flex-wrap: wrap; gap: 0.5rem; }
button.tag { cursor: pointer; }
button.tag .dot { background: var(--line-strong); transition: background-color var(--dur-fast); }
button.tag[aria-pressed="true"] { border-color: var(--accent); color: var(--accent); }
button.tag[aria-pressed="true"] .dot { background: var(--accent); }
.demo-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 0.75rem; margin-top: 1.5rem; }
.demo-out:not(:empty) { margin-top: 1.5rem; border-top: 1px solid var(--line); padding-top: 1.25rem; }
.demo-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 0.75rem; margin-bottom: 1.25rem; }
.demo-head .t { font-family: var(--font-display); font-weight: 600; font-size: 1.0625rem; }
.demo-note { margin: 1.25rem 0 0; font-family: var(--font-mono); font-size: 10px; text-transform: uppercase; letter-spacing: 0.14em; color: var(--ink-faint); }
.q + .q { border-top: 1px solid var(--line); padding-top: 1rem; margin-top: 1rem; }
.q .qt { display: flex; gap: 0.625rem; font-size: 0.9375rem; }
.q .qn { flex: none; font-family: var(--font-mono); font-size: 11px; color: var(--accent); padding-top: 0.2rem; }
.q ol { list-style: none; margin: 0.625rem 0 0 1.75rem; padding: 0; display: grid; gap: 0.25rem; }
.q li { display: flex; gap: 0.5rem; font-size: 0.875rem; color: var(--ink-muted); }
.q li .k { font-family: var(--font-mono); font-size: 11px; color: var(--ink-faint); }
.show-ans .q li.right, .show-ans .q li.right .k { color: var(--accent); }
.show-ans .q li.right::after { content: "✓"; font-family: var(--font-mono); font-size: 11px; }
.sk-row { display: grid; gap: 0.5rem; }
.sk { height: 12px; }

/* — Product screenshots — */
.shot { margin: 0; }
.shot .frame { overflow: hidden; border-radius: var(--r-lg); border: 1px solid var(--line); background: var(--surface-2); aspect-ratio: 9/16; transition: border-color var(--dur-fast); }
.shot:hover .frame { border-color: var(--line-strong); }
.shot img { display: block; width: 100%; height: 100%; object-fit: cover; object-position: top center; }
.shot figcaption { margin-top: 0.75rem; font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.16em; color: var(--ink-faint); }

/* — Numbered steps — */
.step .num { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.18em; color: var(--accent); }
.step h3 { font-family: var(--font-display); font-weight: 600; font-size: 1.0625rem; margin: 0.625rem 0 0.5rem; }
.step p { margin: 0; font-size: 0.875rem; color: var(--ink-muted); }

/* — Stat row — */
.stat { font-family: var(--font-display); font-weight: 700; font-size: 2.5rem; line-height: 1; letter-spacing: -0.02em; }
.stat.txt { font-size: 1.625rem; padding-top: 0.6rem; }

/* ==================================================================== */
/*  9. SCHEMATIC DIAGRAMS                                                */
/* ==================================================================== */
.dgm-scroll { overflow-x: auto; }
.dgm { display: block; width: 100%; min-width: 880px; height: auto; color: var(--ink-faint); }
.dgm .node { fill: var(--surface-2); }
.dgm .pane { fill: none; stroke-dasharray: 4 6; }
.dgm text { stroke: none; fill: currentColor; font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.14em; }
.dgm .t { fill: var(--ink); font-size: 11.5px; letter-spacing: 0.16em; }
.dgm .accent { color: var(--accent); }
.dgm .ck, .dgm .gate { fill: var(--surface-2); }
.dgm-cap { margin-top: 1.5rem; }
.dgm-foot { margin: 1.25rem 0 0; font-family: var(--font-mono); font-size: 10px; text-transform: uppercase; letter-spacing: 0.14em; color: var(--ink-faint); }

/* Draw-on: gated behind .has-reveal, so no-JS / reduced-motion renders complete. */
.has-reveal .flow { stroke-dasharray: 1; stroke-dashoffset: 1; }
.has-reveal .revealed .flow { stroke-dashoffset: 0; transition: stroke-dashoffset 1.2s var(--ease-out-expo); }
.has-reveal .ck, .has-reveal .gate { opacity: 0; }
.has-reveal .revealed .ck, .has-reveal .revealed .gate { opacity: 1; transition: opacity 0.45s var(--ease-out-expo); }
@media (prefers-reduced-motion: reduce) {
  .has-reveal .flow { stroke-dashoffset: 0; }
  .has-reveal .ck, .has-reveal .gate { opacity: 1; }
}

.site-footer { border-top: 1px solid var(--line); margin-top: 4rem; padding: 2.5rem 0; font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.14em; color: var(--ink-faint); display: flex; justify-content: center; flex-wrap: wrap; gap: 0.5rem 2rem; text-align: center; }