/* ===================================================================
   aha. — AI study companion landing
   =================================================================== */

:root {
  /* ink / dark */
  --ink: #0a0a0e;
  --ink-2: #111118;
  --ink-3: #18181f;

  /* paper / light */
  --paper: #f7f6f2;
  --paper-2: #ffffff;
  --paper-edge: rgba(16,16,22,0.08);

  /* text */
  --t-strong: #14141a;
  --t-body: #45454f;
  --t-muted: #7a7a86;
  --t-on-dark: #ffffff;
  --t-on-dark-soft: rgba(255,255,255,0.62);

  /* accents */
  --indigo: #5b4ff0;
  --indigo-soft: #ece9ff;
  --indigo-deep: #3a30b8;
  --amber: #f5933b;
  --amber-soft: #fff0e0;

  --accent: var(--indigo);

  --radius: 22px;
  --radius-lg: 30px;
  --shadow-soft: 0 12px 40px rgba(16,16,22,0.08);
  --shadow-lift: 0 28px 70px rgba(16,16,22,0.16);

  --maxw: 1180px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--paper);
  color: var(--t-body);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

.serif { font-family: 'Playfair Display', Georgia, serif; }

::selection { background: var(--accent); color: #fff; }

/* ---------- shared layout ---------- */
.wrap { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 32px; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}
.eyebrow::before {
  content: "";
  width: 22px; height: 1.5px;
  background: currentColor;
  opacity: 0.55;
}

.section-head { max-width: 640px; }
.section-head .eyebrow { color: var(--accent); margin-bottom: 18px; }
.section-head h2 {
  font-family: 'Playfair Display', serif;
  font-weight: 600;
  color: var(--t-strong);
  font-size: clamp(32px, 4.6vw, 56px);
  line-height: 1.04;
  letter-spacing: -0.01em;
}
.section-head p {
  margin-top: 18px;
  font-size: 18px;
  line-height: 1.6;
  color: var(--t-muted);
  max-width: 540px;
}

/* ===================================================================
   NAV
   =================================================================== */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 32px;
  transition: background 0.4s var(--ease), backdrop-filter 0.4s var(--ease),
              box-shadow 0.4s var(--ease), padding 0.4s var(--ease);
}
.nav.scrolled {
  background: rgba(247,246,242,0.82);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow: 0 1px 0 var(--paper-edge);
  padding: 14px 32px;
}
.brand {
  display: flex; align-items: center; gap: 10px;
  font-family: 'Playfair Display', serif;
  font-size: 23px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: #fff;
  text-decoration: none;
  transition: color 0.4s var(--ease);
}
.brand__word { display: inline; white-space: nowrap; }
.nav.scrolled .brand { color: var(--t-strong); }
.brand .dot { color: var(--accent); }
.brand__mark {
  width: 30px; height: 30px; border-radius: 9px;
  background: var(--accent);
  display: grid; place-items: center;
  box-shadow: 0 4px 16px rgba(91,79,240,0.45);
}
.brand__mark svg { width: 17px; height: 17px; }

.nav__links { display: flex; align-items: center; gap: 34px; }
.nav__links a {
  font-size: 14.5px; font-weight: 500; text-decoration: none;
  color: var(--t-on-dark-soft);
  transition: color 0.25s var(--ease);
}
.nav__links a:hover { color: #fff; }
.nav.scrolled .nav__links a { color: var(--t-muted); }
.nav.scrolled .nav__links a:hover { color: var(--t-strong); }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: inherit; font-size: 14.5px; font-weight: 600;
  padding: 11px 22px; border-radius: 999px; cursor: pointer;
  border: none; text-decoration: none;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease),
              background 0.25s var(--ease), color 0.25s var(--ease);
}
.btn--primary {
  background: var(--accent); color: #fff;
  box-shadow: 0 8px 24px rgba(91,79,240,0.38);
}
.btn--primary:hover { transform: translateY(-2px); box-shadow: 0 14px 34px rgba(91,79,240,0.48); }
.btn--ghost-light {
  background: rgba(255,255,255,0.1);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.22);
  backdrop-filter: blur(8px);
}
.btn--ghost-light:hover { background: rgba(255,255,255,0.18); }
.btn--dark { background: var(--ink); color: #fff; }
.btn--dark:hover { transform: translateY(-2px); box-shadow: var(--shadow-lift); }
.nav__cta-mobile { display: none; }

@media (max-width: 820px) {
  .nav__links a { display: none; }
}

/* ===================================================================
   HERO
   =================================================================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: var(--ink);
}
.hero__video {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  object-fit: cover; z-index: 0;
}
.hero__vignette {
  position: absolute; inset: 0; z-index: 1; pointer-events: none;
  background:
    radial-gradient(ellipse 90% 80% at 50% 42%, rgba(10,10,14,0) 30%, rgba(10,10,14,0.55) 78%, rgba(10,10,14,0.85) 100%),
    linear-gradient(to bottom, rgba(10,10,14,0.5) 0%, rgba(10,10,14,0) 28%, rgba(10,10,14,0) 60%, var(--paper) 100%);
}
.hero__grain {
  position: absolute; inset: -50%; z-index: 2; pointer-events: none;
  opacity: 0.05;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-size: 220px 220px;
  animation: grain 0.7s steps(4) infinite;
}
body.no-grain .hero__grain { display: none; }
@keyframes grain {
  0%{transform:translate(0,0)} 25%{transform:translate(-4%,3%)}
  50%{transform:translate(3%,-4%)} 75%{transform:translate(-3%,-2%)} 100%{transform:translate(2%,4%)}
}

/* directional scrim so headline pops over bright video frames */
.hero__scrim {
  position: absolute; inset: 0; z-index: 2; pointer-events: none;
  background:
    linear-gradient(100deg, rgba(8,8,12,0.82) 0%, rgba(8,8,12,0.55) 38%, rgba(8,8,12,0.18) 64%, rgba(8,8,12,0) 88%),
    linear-gradient(to top, rgba(8,8,12,0.6) 0%, rgba(8,8,12,0) 38%);
}
.hero__particles {
  position: absolute; inset: 0; z-index: 2; pointer-events: none; opacity: 0.6;
}

.hero__inner {
  position: relative; z-index: 3;
  width: 100%; max-width: var(--maxw);
  margin: 0 auto; padding: 0 32px;
}
.hero__eyebrow {
  color: rgba(255,255,255,0.88);
  margin-bottom: 26px;
  text-shadow: 0 1px 16px rgba(0,0,0,0.6);
}
.hero h1 {
  font-family: 'Playfair Display', serif;
  font-weight: 600;
  color: #fff;
  font-size: clamp(44px, 8vw, 104px);
  line-height: 0.98;
  letter-spacing: -0.02em;
  max-width: 16ch;
  text-shadow: 0 2px 50px rgba(0,0,0,0.7), 0 1px 3px rgba(0,0,0,0.5);
}
.hero h1 em {
  font-style: italic;
  background: linear-gradient(100deg, #8576ff 0%, #c9c2ff 48%, #8576ff 100%);
  background-size: 220% auto;
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 3px 34px rgba(91,79,240,0.6));
  animation: shimmer 5s linear infinite;
}
@keyframes shimmer { to { background-position: 220% center; } }
.hero__sub {
  margin-top: 26px;
  font-size: clamp(16px, 1.5vw, 20px);
  line-height: 1.6;
  color: rgba(255,255,255,0.86);
  max-width: 50ch;
  text-shadow: 0 1px 24px rgba(0,0,0,0.6);
}

/* hero teaser input */
.askbar {
  margin-top: 40px;
  display: flex; align-items: center; gap: 10px;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.18);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: 18px;
  padding: 10px 10px 10px 22px;
  max-width: 580px;
  box-shadow: 0 20px 50px rgba(0,0,0,0.35);
}
.askbar__text {
  flex: 1; min-width: 0;
  display: flex; flex-direction: column; gap: 2px;
}
.askbar__typed {
  font-size: 16px; color: #fff; font-weight: 500;
  white-space: nowrap; overflow: hidden;
}
.askbar__typed .caret {
  display: inline-block; width: 2px; height: 1.05em;
  background: var(--accent); margin-left: 2px;
  vertical-align: -2px;
  animation: blink 1s steps(2) infinite;
}
@keyframes blink { 0%,50%{opacity:1} 50.01%,100%{opacity:0} }
.askbar__modes { display: flex; gap: 6px; }
.askbar__mode {
  width: 42px; height: 42px; border-radius: 12px;
  display: grid; place-items: center;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.12);
  color: rgba(255,255,255,0.7);
  cursor: pointer; transition: all 0.25s var(--ease);
}
.askbar__mode:hover { background: rgba(255,255,255,0.16); color:#fff; }
.askbar__mode svg { width: 18px; height: 18px; }
.askbar__send {
  width: 42px; height: 42px; border-radius: 12px;
  background: var(--accent); color: #fff; border: none;
  display: grid; place-items: center; cursor: pointer;
  box-shadow: 0 6px 18px rgba(91,79,240,0.45);
  transition: transform 0.25s var(--ease);
}
.askbar__send:hover { transform: scale(1.06); }
.askbar__send svg { width: 18px; height: 18px; }

.scroll-cue {
  position: absolute; bottom: 30px; left: 50%; transform: translateX(-50%);
  z-index: 3;
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  color: rgba(255,255,255,0.5);
  font-size: 11.5px; letter-spacing: 0.18em; text-transform: uppercase;
}
.scroll-cue .mouse {
  width: 22px; height: 34px; border: 1.5px solid rgba(255,255,255,0.4);
  border-radius: 12px; position: relative;
}
.scroll-cue .mouse::after {
  content:""; position: absolute; top: 6px; left: 50%; transform: translateX(-50%);
  width: 3px; height: 6px; border-radius: 2px; background: rgba(255,255,255,0.7);
  animation: wheel 1.6s var(--ease) infinite;
}
@keyframes wheel { 0%{opacity:0;transform:translate(-50%,0)} 30%{opacity:1} 70%{opacity:1} 100%{opacity:0;transform:translate(-50%,12px)} }

/* ===================================================================
   reveal util
   =================================================================== */
.reveal { opacity: 0; transform: translateY(34px); transition: opacity 0.9s var(--ease), transform 0.9s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
.reveal.d1 { transition-delay: 0.08s; }
.reveal.d2 { transition-delay: 0.16s; }
.reveal.d3 { transition-delay: 0.24s; }
.reveal.d4 { transition-delay: 0.32s; }

/* ===================================================================
   INPUT MODES SECTION
   =================================================================== */
.modes {
  background: var(--paper);
  padding: 130px 0 110px;
}
.modes__head { display: flex; justify-content: space-between; align-items: flex-end; gap: 40px; flex-wrap: wrap; margin-bottom: 64px; }
.modes__grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.mode-card {
  background: var(--paper-2);
  border: 1px solid var(--paper-edge);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-soft);
  transition: transform 0.4s var(--ease), box-shadow 0.4s var(--ease);
}
.mode-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lift); }
.mode-card__icon {
  width: 54px; height: 54px; border-radius: 16px;
  display: grid; place-items: center;
  background: var(--indigo-soft); color: var(--accent);
  margin-bottom: 26px;
}
.mode-card__icon svg { width: 26px; height: 26px; }
.mode-card h3 { font-size: 21px; font-weight: 700; color: var(--t-strong); margin-bottom: 9px; letter-spacing:-0.01em; }
.mode-card p { font-size: 15px; line-height: 1.62; color: var(--t-muted); }
.mode-card__demo {
  margin-top: 26px; border-top: 1px solid var(--paper-edge); padding-top: 22px;
  min-height: 70px; display: flex; align-items: center;
}
/* type demo */
.td-line { font-size: 14px; color: var(--t-body); }
.td-line .cw { color: var(--accent); font-weight: 600; }
/* photo demo */
.photo-chip {
  display: inline-flex; align-items: center; gap: 10px;
  background: var(--paper); border: 1px solid var(--paper-edge);
  border-radius: 12px; padding: 8px 14px 8px 8px; font-size: 13px; color: var(--t-body);
}
.photo-chip .thumb {
  width: 38px; height: 38px; border-radius: 8px;
  background: linear-gradient(135deg, #2a2a35, #4a4a5e);
  position: relative; overflow: hidden; flex: none;
}
.photo-chip .thumb::after {
  content:""; position:absolute; inset:0;
  background: repeating-linear-gradient(0deg, rgba(255,255,255,0.18) 0 2px, transparent 2px 8px);
}
/* audio demo */
.wave { display: flex; align-items: center; gap: 4px; height: 36px; }
.wave span {
  width: 4px; border-radius: 3px; background: var(--accent); opacity: 0.85;
  animation: wv 1.1s ease-in-out infinite;
}
@keyframes wv { 0%,100%{height:8px} 50%{height:30px} }

/* ===================================================================
   STUDIO — pinned deck-generation sequence
   =================================================================== */
.studio { position: relative; background: var(--ink); height: 360vh; }
.studio__sticky {
  position: sticky; top: 0;
  height: 100vh;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  gap: clamp(12px, 2vh, 26px);
  overflow: hidden;
}
.studio__glow {
  position: absolute; width: 900px; height: 900px; border-radius: 50%;
  background: radial-gradient(circle, rgba(91,79,240,0.22), transparent 60%);
  top: 50%; left: 50%; transform: translate(-50%,-50%);
  filter: blur(20px); pointer-events: none;
  transition: opacity 0.6s var(--ease);
}
.studio__label {
  position: relative; z-index: 2;
  text-align: center;
}
.studio__label .eyebrow { color: rgba(255,255,255,0.6); }
.studio__label h2 {
  font-family: 'Playfair Display', serif; font-weight: 600;
  color: #fff; font-size: clamp(26px, 3.4vw, 40px); margin-top: 12px;
  letter-spacing: -0.01em;
}

/* the screen / window mock */
.screen {
  position: relative; z-index: 2;
  width: min(880px, 92vw);
  height: min(496px, 56vh);
  background: #0f0f16;
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 18px;
  box-shadow: 0 40px 120px rgba(0,0,0,0.6);
  overflow: hidden;
  display: flex; flex-direction: column;
}
.screen__bar {
  height: 42px; flex: none;
  display: flex; align-items: center; gap: 8px;
  padding: 0 16px;
  background: #15151d;
  border-bottom: 1px solid rgba(255,255,255,0.07);
}
.screen__bar .dot3 { width: 11px; height: 11px; border-radius: 50%; }
.screen__bar .r{background:#ff5f57} .screen__bar .y{background:#febc2e} .screen__bar .g{background:#28c840}
.screen__bar .url {
  margin-left: 14px; font-size: 12px; color: rgba(255,255,255,0.4);
  background: rgba(255,255,255,0.06); border-radius: 8px; padding: 5px 14px;
}
.screen__body { flex: 1; position: relative; }

/* stages stacked */
.stage {
  position: absolute; inset: 0;
  padding: 30px 36px;
  opacity: 0; transform: translateY(14px) scale(0.99);
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
  pointer-events: none;
  display: flex; flex-direction: column;
}
.stage.active { opacity: 1; transform: none; }

/* stage: prompt */
.stage--prompt { justify-content: center; align-items: center; text-align: center; }
.stage--prompt .promptbox {
  width: 100%; max-width: 560px;
  background: #16161f; border: 1px solid rgba(255,255,255,0.1);
  border-radius: 16px; padding: 22px 24px;
  display: flex; align-items: center; gap: 14px;
}
.stage--prompt .promptbox .q { font-size: clamp(15px,1.9vw,20px); color: #fff; text-align: left; flex:1; }
.stage--prompt .hint { margin-top: 22px; font-size: 13px; color: rgba(255,255,255,0.4); }

/* stage: thinking */
.stage--think { justify-content: center; align-items: center; }
.think-orb {
  width: 92px; height: 92px; border-radius: 50%;
  background: conic-gradient(from 0deg, var(--accent), #8b7bff, var(--accent));
  filter: blur(2px); animation: spin 2.4s linear infinite;
  box-shadow: 0 0 60px rgba(91,79,240,0.6);
}
@keyframes spin { to { transform: rotate(360deg); } }
.think-steps { margin-top: 30px; display: flex; flex-direction: column; gap: 10px; }
.think-steps li {
  list-style: none; font-size: 14px; color: rgba(255,255,255,0.5);
  display: flex; align-items: center; gap: 10px;
}
.think-steps li .tick {
  width: 16px; height: 16px; border-radius: 50%; border: 1.5px solid rgba(255,255,255,0.25);
  display: grid; place-items: center; flex: none;
}
.think-steps li.done { color: rgba(255,255,255,0.9); }
.think-steps li.done .tick { background: var(--accent); border-color: var(--accent); }
.think-steps li.done .tick svg { width: 9px; height: 9px; }

/* deck stages share slide canvas */
.slide-canvas {
  flex: 1;
  background: #fbfaf7; border-radius: 12px;
  overflow: hidden; position: relative;
  display: flex; flex-direction: column;
  color: #14141a;
}
.slide-top {
  display:flex; align-items:center; justify-content:space-between;
  padding: 16px 26px; border-bottom: 1px solid rgba(16,16,22,0.07);
}
.slide-top .kicker { font-size: 11px; font-weight: 700; letter-spacing: 0.14em; text-transform: uppercase; color: var(--accent); }
.slide-top .pg { font-size: 12px; color: var(--t-muted); }
.slide-main { flex:1; padding: 22px 30px; display:flex; flex-direction:column; }
.slide-main h3 {
  font-family:'Playfair Display',serif; font-weight:600;
  font-size: clamp(20px,2.6vw,30px); line-height:1.08; letter-spacing:-0.01em; margin-bottom: 6px;
}

/* flowchart */
.flow { display:flex; align-items:center; gap: 10px; flex-wrap: wrap; margin-top: auto; margin-bottom: auto; }
.flow .node {
  background:#fff; border:1.5px solid var(--indigo); color: var(--indigo-deep);
  font-size: clamp(11px,1.4vw,14px); font-weight:600;
  padding: 12px 16px; border-radius: 12px; text-align:center; flex:1; min-width: 90px;
  box-shadow: 0 6px 16px rgba(91,79,240,0.12);
}
.flow .node.alt { border-color: var(--amber); color:#b5651d; box-shadow:0 6px 16px rgba(245,147,59,0.14); }
.flow .arrow { color: var(--t-muted); flex:none; font-size: 20px; }

/* diagram (schematic) */
.diagram { display:grid; grid-template-columns: 1.1fr 1fr; gap: 22px; flex:1; align-items:center; }
.diagram__viz {
  position: relative; height: 100%; min-height: 150px;
  background: linear-gradient(135deg,#eef0ff,#f8f4ff);
  border:1px solid var(--paper-edge); border-radius: 14px;
  display:grid; place-items:center;
}
.cell {
  width: 70%; height: 64%; border-radius: 16px;
  background: #fff; border: 2px solid var(--indigo);
  position: relative;
}
.cell .organelle {
  position:absolute; border-radius: 50%;
}
.cell .nucleus{ width:32%; height:32%; background:var(--amber); top:20%; left:22%; }
.cell .chloro{ width:22%; height:30%; background:var(--indigo); border-radius:40%; bottom:18%; right:20%; transform:rotate(20deg); }
.cell .chloro2{ width:18%; height:24%; background:#8b7bff; border-radius:40%; top:24%; right:24%; transform:rotate(-15deg); }
.diagram__legend { display:flex; flex-direction:column; gap: 12px; }
.diagram__legend .lg { display:flex; align-items:flex-start; gap:10px; font-size: clamp(11px,1.4vw,13.5px); }
.diagram__legend .sw { width:14px;height:14px;border-radius:4px;flex:none;margin-top:2px; }
.diagram__legend .t b { display:block; color:var(--t-strong); font-size: clamp(12px,1.5vw,14px); }
.diagram__legend .t span { color: var(--t-muted); }

/* explanation */
.explain { display:flex; flex-direction:column; gap: 12px; margin-top: 10px; }
.explain .pt { display:flex; gap: 12px; align-items:flex-start; }
.explain .pt .n {
  width: 24px; height: 24px; border-radius: 50%; background: var(--indigo-soft); color: var(--indigo-deep);
  font-size: 12px; font-weight: 700; display:grid; place-items:center; flex:none;
}
.explain .pt p { font-size: clamp(12px,1.6vw,15px); line-height: 1.5; color: var(--t-body); }
.explain .pt p b { color: var(--t-strong); }

/* filmstrip / progress */
.studio__rail {
  position: relative; z-index: 2;
  display: flex; gap: 12px; align-items: center;
}
.rail-step {
  display:flex; align-items:center; gap: 10px;
  padding: 8px 16px; border-radius: 999px;
  background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.1);
  color: rgba(255,255,255,0.45); font-size: 13px; font-weight: 500;
  transition: all 0.4s var(--ease);
}
.rail-step .ix {
  width: 20px; height: 20px; border-radius: 50%;
  background: rgba(255,255,255,0.1); display:grid; place-items:center;
  font-size: 11px; font-weight:700;
}
.rail-step.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.rail-step.active .ix { background: rgba(255,255,255,0.25); }
.rail-step.passed { color: rgba(255,255,255,0.8); }

@media (max-width: 720px) {
  .studio__rail { display:none; }
  .diagram { grid-template-columns: 1fr; }
}

/* ===================================================================
   DIAGRAMS feature strip (light)
   =================================================================== */
.feature {
  background: var(--paper-2);
  padding: 120px 0;
}
.feature__row {
  display: grid; grid-template-columns: 1fr 1fr; gap: 70px; align-items: center;
}
.feature__row.flip .feature__media { order: -1; }
.feature__media {
  position: relative;
  background: var(--paper);
  border: 1px solid var(--paper-edge);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
  padding: 36px;
  min-height: 380px;
  display: flex; align-items: center; justify-content: center;
}
.feature h2 { font-family:'Playfair Display',serif; font-weight:600; color:var(--t-strong); font-size: clamp(28px,3.6vw,46px); line-height:1.05; letter-spacing:-0.01em; }
.feature .eyebrow { color: var(--accent); margin-bottom: 16px; }
.feature p.lead { margin-top: 18px; font-size: 17px; line-height:1.62; color: var(--t-muted); }
.feature .bullets { margin-top: 26px; display:flex; flex-direction:column; gap: 14px; }
.feature .bullets li { list-style:none; display:flex; gap:12px; align-items:flex-start; font-size:15px; color:var(--t-body); }
.feature .bullets .ck {
  width:22px;height:22px;border-radius:50%;background:var(--indigo-soft);color:var(--accent);
  display:grid;place-items:center;flex:none;margin-top:1px;
}
.feature .bullets .ck svg{width:11px;height:11px;}

/* big flowchart art inside media */
.flow-art { width:100%; display:flex; flex-direction:column; gap:14px; }
.flow-art .fnode {
  background:#fff;border:1.5px solid var(--indigo);border-radius:12px;
  padding:14px 18px; font-size:14px; font-weight:600; color:var(--indigo-deep);
  box-shadow:0 6px 18px rgba(91,79,240,0.12); position:relative;
}
.flow-art .fnode.amber{border-color:var(--amber);color:#b5651d;}
.flow-art .branch{display:flex;gap:14px;}
.flow-art .branch .fnode{flex:1;}
.flow-art .conn{height:16px;width:2px;background:var(--paper-edge);margin:0 auto;}

/* staggered build-in of the flowchart on reveal */
.flow-art > * { opacity: 0; transform: translateY(16px); transition: opacity 0.6s var(--ease), transform 0.6s var(--ease); }
.feature__media.in .flow-art > * { opacity: 1; transform: none; }
.feature__media.in .flow-art > *:nth-child(1){transition-delay:0.10s}
.feature__media.in .flow-art > *:nth-child(2){transition-delay:0.20s}
.feature__media.in .flow-art > *:nth-child(3){transition-delay:0.30s}
.feature__media.in .flow-art > *:nth-child(4){transition-delay:0.42s}
.feature__media.in .flow-art > *:nth-child(5){transition-delay:0.54s}
.feature__media.in .flow-art > *:nth-child(6){transition-delay:0.66s}
.feature__media.in .flow-art > *:nth-child(7){transition-delay:0.78s}

@media (max-width: 860px) {
  .feature__row { grid-template-columns: 1fr; gap: 40px; }
  .feature__row.flip .feature__media { order: 0; }
}

/* ===================================================================
   NARRATION (dark)
   =================================================================== */
.narrate {
  background: var(--ink-2);
  padding: 120px 0;
  color: #fff;
  position: relative; overflow:hidden;
}
.narrate__glow {
  position:absolute; width:700px;height:700px;border-radius:50%;
  background:radial-gradient(circle,rgba(245,147,59,0.16),transparent 60%);
  top:-160px;right:-160px;filter:blur(10px);pointer-events:none;
}
.narrate__grid { display:grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items:center; }
.narrate .eyebrow { color: var(--amber); margin-bottom:16px; }
.narrate h2 { font-family:'Playfair Display',serif;font-weight:600;font-size:clamp(30px,4vw,52px);line-height:1.03;letter-spacing:-0.01em; }
.narrate p.lead { margin-top:18px;font-size:17px;line-height:1.62;color:var(--t-on-dark-soft);max-width:46ch; }

.player {
  background: #0d0d14; border:1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius-lg); padding: 30px; box-shadow: 0 30px 80px rgba(0,0,0,0.5);
}
.player__slide {
  background:#fbfaf7;border-radius:14px;padding:24px;color:#14141a;min-height:180px;
  display:flex;flex-direction:column;
}
.player__slide .kicker{font-size:10.5px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--accent);}
.player__slide h4{font-family:'Playfair Display',serif;font-weight:600;font-size:22px;margin:8px 0 12px;}
.player__slide .cap {
  font-size:15px;line-height:1.55;color:var(--t-body);
}
.player__slide .cap .hl { background: var(--amber-soft); box-shadow:0 0 0 3px var(--amber-soft); border-radius:3px; }
.player__controls { display:flex; align-items:center; gap:16px; margin-top:22px; }
.player__play {
  width:50px;height:50px;border-radius:50%;background:var(--amber);color:#fff;border:none;
  display:grid;place-items:center;cursor:pointer;flex:none;box-shadow:0 8px 22px rgba(245,147,59,0.5);
  transition: transform 0.25s var(--ease);
}
.player__play:hover{transform:scale(1.06);}
.player__play svg{width:18px;height:18px;}
.player__wave { flex:1; display:flex; align-items:center; gap:3px; height:42px; }
.player__wave span {
  flex:1; background: rgba(255,255,255,0.18); border-radius:3px; height:20%;
  transition: height 0.15s ease, background 0.15s ease;
}
.player__wave span.on { background: var(--amber); }
.player__avatar {
  display:flex;align-items:center;gap:12px;margin-bottom:20px;
}
.player__orb{
  width:38px;height:38px;border-radius:50%;
  background:conic-gradient(from 0deg,var(--amber),#ffd28a,var(--amber));
  box-shadow:0 0 24px rgba(245,147,59,0.5);flex:none;
}
.player__avatar .who b{display:block;font-size:14px;color:#fff;}
.player__avatar .who span{font-size:12px;color:var(--t-on-dark-soft);}

@media (max-width:860px){ .narrate__grid{grid-template-columns:1fr;gap:40px;} }

/* ===================================================================
   DEPTH SLIDER (light)
   =================================================================== */
.depth { background: var(--paper); padding: 120px 0; }
.depth__head { text-align:center; max-width:620px; margin:0 auto 56px; }
.depth__head .eyebrow{color:var(--accent);justify-content:center;margin-bottom:16px;}
.depth__head .eyebrow::before{display:none;}
.depth__head h2{font-family:'Playfair Display',serif;font-weight:600;color:var(--t-strong);font-size:clamp(30px,4vw,52px);line-height:1.04;letter-spacing:-0.01em;}
.depth__head p{margin-top:16px;font-size:18px;color:var(--t-muted);}

.depth__panel {
  max-width: 820px; margin: 0 auto;
  background: var(--paper-2); border:1px solid var(--paper-edge);
  border-radius: var(--radius-lg); box-shadow: var(--shadow-soft);
  padding: 44px;
}
.depth__levels { display:flex; justify-content:space-between; margin-bottom: 8px; }
.depth__levels button {
  background:none;border:none;font-family:inherit;cursor:pointer;
  font-size:14px;font-weight:600;color:var(--t-muted);padding:6px 4px;
  transition:color 0.25s var(--ease);
}
.depth__levels button.active{color:var(--accent);}
.depth__track { position:relative; height:6px; background:var(--indigo-soft); border-radius:999px; margin: 14px 0 36px; }
.depth__range {
  -webkit-appearance:none;appearance:none;width:100%;background:transparent;position:absolute;top:-9px;left:0;height:24px;margin:0;cursor:pointer;
}
.depth__range::-webkit-slider-thumb{
  -webkit-appearance:none;width:24px;height:24px;border-radius:50%;background:var(--accent);
  border:4px solid #fff;box-shadow:0 4px 14px rgba(91,79,240,0.5);cursor:pointer;
}
.depth__range::-moz-range-thumb{
  width:24px;height:24px;border-radius:50%;background:var(--accent);
  border:4px solid #fff;box-shadow:0 4px 14px rgba(91,79,240,0.5);cursor:pointer;
}
.depth__fill{position:absolute;top:0;left:0;height:100%;background:var(--accent);border-radius:999px;transition:width 0.3s var(--ease);}
.depth__content { min-height: 150px; }
.depth__tag {
  display:inline-block;font-size:12px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;
  color:var(--accent);background:var(--indigo-soft);padding:6px 14px;border-radius:999px;margin-bottom:18px;
}
.depth__text { font-size: clamp(17px,2.2vw,22px); line-height:1.6; color:var(--t-strong); font-weight:500; }
.depth__text.mono { font-family: 'Plus Jakarta Sans', monospace; }
.depth__text .v { color: var(--accent); font-weight:700; }

/* ===================================================================
   LIBRARY + STREAK (dark)
   =================================================================== */
.library { background: var(--ink); padding: 120px 0; color:#fff; }
.library__head{ display:flex;justify-content:space-between;align-items:flex-end;gap:40px;flex-wrap:wrap;margin-bottom:54px; }
.library .eyebrow{color:rgba(255,255,255,0.6);margin-bottom:16px;}
.library h2{font-family:'Playfair Display',serif;font-weight:600;font-size:clamp(30px,4vw,52px);line-height:1.04;letter-spacing:-0.01em;}
.library__grid{ display:grid;grid-template-columns: 1.7fr 1fr; gap:24px; }
.doubts{ display:grid;grid-template-columns:repeat(2,1fr);gap:16px; }
.doubt {
  background: var(--ink-3); border:1px solid rgba(255,255,255,0.08);
  border-radius: 18px; padding: 22px;
  transition: transform 0.35s var(--ease), border-color 0.35s var(--ease);
}
.doubt:hover{ transform: translateY(-5px); border-color: rgba(91,79,240,0.5); }
.doubt__tag{ display:inline-block;font-size:11px;font-weight:600;letter-spacing:.06em;color:var(--accent);background:rgba(91,79,240,0.14);padding:4px 10px;border-radius:999px;margin-bottom:14px; }
.doubt__tag.bio{color:#5fd0a0;background:rgba(95,208,160,0.14);}
.doubt__tag.phy{color:#f5933b;background:rgba(245,147,59,0.14);}
.doubt__tag.math{color:#6ba8ff;background:rgba(107,168,255,0.14);}
.doubt h4{ font-size:16px;font-weight:600;color:#fff;line-height:1.3;margin-bottom:10px; }
.doubt__meta{ font-size:12.5px;color:var(--t-on-dark-soft);display:flex;gap:10px;align-items:center; }
.doubt__meta .slides{ display:inline-flex;align-items:center;gap:5px; }

.streak {
  background: linear-gradient(160deg,#1a1530,#14141d);
  border:1px solid rgba(255,255,255,0.1); border-radius:18px; padding: 28px;
  display:flex;flex-direction:column;
}
.streak__flame{ font-size:0; } /* replaced by svg */
.streak__num{ font-family:'Playfair Display',serif;font-size:64px;font-weight:700;line-height:1;color:#fff; display:flex;align-items:baseline;gap:10px; }
.streak__num .fire{width:40px;height:46px;}
.streak__lbl{ font-size:14px;color:var(--t-on-dark-soft);margin-top:8px; }
.streak__week{ display:flex;gap:8px;margin-top:auto;padding-top:28px; }
.streak__day{ flex:1;display:flex;flex-direction:column;align-items:center;gap:7px; }
.streak__day .d{ width:100%;aspect-ratio:1;border-radius:8px;background:rgba(255,255,255,0.07); }
.streak__day.on .d{ background:var(--amber);box-shadow:0 0 16px rgba(245,147,59,0.4); }
.streak__day .lbl{ font-size:10px;color:var(--t-on-dark-soft); }

@media (max-width: 860px){
  .library__grid{ grid-template-columns:1fr; }
  .doubts{ grid-template-columns:1fr; }
}

/* ===================================================================
   CTA + FOOTER
   =================================================================== */
.cta {
  background: var(--paper-2);
  padding: 140px 0 110px; text-align:center;
}
.cta h2{ font-family:'Playfair Display',serif;font-weight:600;color:var(--t-strong);font-size:clamp(36px,6vw,80px);line-height:1.0;letter-spacing:-0.02em;max-width:14ch;margin:0 auto; }
.cta h2 em{font-style:italic;color:var(--accent);}
.cta p{ margin:24px auto 0;font-size:19px;color:var(--t-muted);max-width:48ch; }
.cta__form{ margin:40px auto 0;display:flex;gap:10px;max-width:480px; }
.cta__form input{
  flex:1;font-family:inherit;font-size:15px;padding:15px 20px;border-radius:999px;
  border:1px solid var(--paper-edge);background:var(--paper);color:var(--t-strong);outline:none;
  transition:border-color 0.25s var(--ease);
}
.cta__form input:focus{border-color:var(--accent);}
.cta__note{ margin-top:18px;font-size:13px;color:var(--t-muted); }

.footer{ background: var(--ink); color:#fff; padding: 70px 0 50px; }
.footer__top{ display:flex;justify-content:space-between;gap:40px;flex-wrap:wrap;border-bottom:1px solid rgba(255,255,255,0.1);padding-bottom:40px; }
.footer .brand{color:#fff;}
.footer__tag{ font-size:14px;color:var(--t-on-dark-soft);max-width:30ch;margin-top:16px;line-height:1.6; }
.footer__cols{ display:flex;gap:64px;flex-wrap:wrap; }
.footer__col h5{ font-size:13px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:rgba(255,255,255,0.5);margin-bottom:16px; }
.footer__col a{ display:block;font-size:14.5px;color:var(--t-on-dark-soft);text-decoration:none;margin-bottom:11px;transition:color 0.2s; }
.footer__col a:hover{color:#fff;}
.footer__bottom{ display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap;padding-top:28px;font-size:13px;color:var(--t-on-dark-soft); }

@media (max-width: 720px){
  .wrap{padding:0 22px;}
  .modes{padding:90px 0 80px;}
  .modes__grid{grid-template-columns:1fr;}
  .cta__form{flex-direction:column;}
  .cta__form .btn{justify-content:center;}
}

/* ===================================================================
   HOW IT WORKS — scroll-driven timeline
   =================================================================== */
.how { background: var(--paper-2); padding: 120px 0 130px; }
.how__head { text-align: center; max-width: 680px; margin: 0 auto 84px; }
.how__head .eyebrow { color: var(--accent); justify-content: center; margin-bottom: 16px; }
.how__head .eyebrow::before { display: none; }
.how__head h2 { font-family:'Playfair Display',serif; font-weight:600; color:var(--t-strong); font-size: clamp(30px,4.4vw,54px); line-height:1.04; letter-spacing:-0.01em; }
.how__head p { margin-top:16px; font-size:18px; color:var(--t-muted); }

.how__timeline { position: relative; max-width: 940px; margin: 0 auto; }
.how__spine { position: absolute; left: 31px; top: 32px; bottom: 90px; width: 2px; background: var(--paper-edge); border-radius: 2px; }
.how__spine-fill { position: absolute; left: 0; top: 0; width: 100%; height: 0; background: linear-gradient(var(--accent), #8b7bff); border-radius: 2px; box-shadow: 0 0 16px rgba(91,79,240,0.5); transition: height 0.12s linear; }

.how-step {
  position: relative;
  display: grid;
  grid-template-columns: 64px minmax(0,0.95fr) minmax(0,1fr);
  gap: 30px 40px; align-items: center;
  padding-bottom: 78px;
}
.how-step:last-child { padding-bottom: 0; }

.how-step__node {
  width: 64px; height: 64px; border-radius: 50%;
  background: var(--paper-2); border: 2px solid var(--paper-edge);
  display: grid; place-items: center; position: relative; z-index: 2;
  transition: all 0.5s var(--ease);
}
.how-step__node .num { font-family:'Playfair Display',serif; font-size: 26px; font-weight:700; color: var(--t-muted); transition: color 0.5s var(--ease); }
.how-step.lit .how-step__node { background: var(--accent); border-color: var(--accent); box-shadow: 0 10px 30px rgba(91,79,240,0.45); transform: scale(1.05); }
.how-step.lit .how-step__node .num { color: #fff; }

.how-step__text h3 { font-family:'Playfair Display',serif; font-weight:600; font-size: clamp(22px,2.8vw,32px); color: var(--t-strong); line-height:1.1; letter-spacing:-0.01em; margin-bottom: 12px; }
.how-step__text p { font-size: 16px; line-height: 1.62; color: var(--t-muted); }
.how-step__text .kicker { display:inline-block; font-size:12px; font-weight:700; letter-spacing:.12em; text-transform:uppercase; color: var(--accent); margin-bottom: 10px; }

/* step content reveal */
.how-step__text, .how-step__mock { opacity: 0; transform: translateY(28px); transition: opacity 0.8s var(--ease), transform 0.8s var(--ease); }
.how-step__mock { transition-delay: 0.12s; }
.how-step.lit .how-step__text, .how-step.lit .how-step__mock { opacity: 1; transform: none; }

/* mock shell */
.how-step__mock { }
.how-mock {
  background: var(--paper); border: 1px solid var(--paper-edge); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft); padding: 26px; min-height: 200px;
  display: flex; flex-direction: column; justify-content: center; gap: 14px;
}

/* step 1 — upload */
.upcard { display:flex; flex-direction:column; gap: 14px; }
.upcard__img {
  height: 120px; border-radius: 14px; position: relative; overflow: hidden;
  background: linear-gradient(135deg,#2a2a35,#454560);
}
.upcard__img::before {
  content:""; position:absolute; inset:0;
  background: repeating-linear-gradient(0deg, rgba(255,255,255,0.16) 0 2px, transparent 2px 9px);
}
.upcard__img::after {
  content:""; position:absolute; left:-40%; top:0; width:40%; height:100%;
  background: linear-gradient(105deg, transparent, rgba(255,255,255,0.35), transparent);
  animation: scan 2.6s var(--ease) infinite;
}
@keyframes scan { 0%{left:-45%} 60%,100%{left:120%} }
.upcard__row { display:flex; align-items:center; gap:10px; font-size:13.5px; color:var(--t-body); font-weight:500; }
.upcard__row .dotpulse { width:9px;height:9px;border-radius:50%;background:#28c840;box-shadow:0 0 0 0 rgba(40,200,64,0.5); animation: pulse 1.8s infinite; flex:none; }
@keyframes pulse { 0%{box-shadow:0 0 0 0 rgba(40,200,64,0.5)} 70%{box-shadow:0 0 0 10px rgba(40,200,64,0)} 100%{box-shadow:0 0 0 0 rgba(40,200,64,0)} }
.upcard__tag { font-weight:700;color:var(--t-strong); }

/* step 2 — deck building */
.how-deck { display:grid; grid-template-columns: repeat(3,1fr); gap: 12px; }
.how-slide {
  aspect-ratio: 4/3; background:#fff; border:1px solid var(--paper-edge); border-radius:10px;
  padding:11px; display:flex; flex-direction:column; gap:6px; box-shadow:0 4px 14px rgba(16,16,22,0.06);
  opacity:0; transform: translateY(14px) scale(0.96);
  animation: slidepop 0.6s var(--ease) forwards;
}
.how-step.lit .how-slide:nth-child(1){animation-delay:.25s}
.how-step.lit .how-slide:nth-child(2){animation-delay:.45s}
.how-step.lit .how-slide:nth-child(3){animation-delay:.65s}
.how-step:not(.lit) .how-slide{ animation:none; opacity:0; }
@keyframes slidepop { to { opacity:1; transform:none; } }
.how-slide .ln { height:5px; border-radius:3px; background: var(--paper-edge); }
.how-slide .ln.title { background: var(--indigo-soft); width:70%; height:8px; }
.how-slide .mini-flow { display:flex; align-items:center; gap:3px; margin-top:auto; }
.how-slide .mini-flow i { flex:1; height:11px; border-radius:3px; background:var(--indigo); opacity:.8; }
.how-slide .mini-flow .ar { flex:none; color:var(--t-muted); font-size:9px; }
.how-slide .mini-dia { margin-top:auto; display:flex; gap:5px; align-items:center; }
.how-slide .mini-dia .cir { width:22px;height:22px;border-radius:6px;border:2px solid var(--indigo);position:relative; }
.how-slide .mini-dia .cir::after{content:"";position:absolute;width:7px;height:7px;border-radius:50%;background:var(--amber);top:4px;left:4px;}
.how-slide .mini-dia .ll{flex:1;display:flex;flex-direction:column;gap:4px;}
.how-slide .mini-dia .ll span{height:4px;border-radius:2px;background:var(--paper-edge);}
.how-deck__cap { grid-column:1/-1; text-align:center; font-size:13px; color:var(--t-muted); margin-top:4px; }

/* step 3 — languages + tutor */
.how-lang__top { display:flex; align-items:center; gap:14px; }
.how-lang__orb {
  width:46px;height:46px;border-radius:50%;flex:none;
  background:conic-gradient(from 0deg,var(--accent),#9b8dff,var(--accent));
  box-shadow:0 0 28px rgba(91,79,240,0.5); animation: spin 3s linear infinite;
}
.how-lang__who b{ display:block;font-size:14px;color:var(--t-strong); }
.how-lang__who span{ font-size:12.5px;color:var(--t-muted); }
.how-lang__chips { display:flex; flex-wrap:wrap; gap:8px; margin-top:6px; }
.how-lang__chips span {
  font-size:13px; font-weight:600; padding:7px 14px; border-radius:999px;
  background:var(--paper-2); border:1px solid var(--paper-edge); color:var(--t-body);
  opacity:0; transform: translateY(8px); animation: chipin 0.5s var(--ease) forwards;
}
.how-step:not(.lit) .how-lang__chips span{ animation:none; opacity:0; }
@keyframes chipin { to { opacity:1; transform:none; } }
.how-lang__chips span.live { background:var(--indigo-soft); border-color:transparent; color:var(--indigo-deep); }
.how-step.lit .how-lang__chips span:nth-child(1){animation-delay:.3s}
.how-step.lit .how-lang__chips span:nth-child(2){animation-delay:.38s}
.how-step.lit .how-lang__chips span:nth-child(3){animation-delay:.46s}
.how-step.lit .how-lang__chips span:nth-child(4){animation-delay:.54s}
.how-step.lit .how-lang__chips span:nth-child(5){animation-delay:.62s}
.how-step.lit .how-lang__chips span:nth-child(6){animation-delay:.70s}
.how-step.lit .how-lang__chips span:nth-child(7){animation-delay:.78s}

@media (max-width: 820px) {
  .how-step { grid-template-columns: 44px 1fr; gap: 18px 20px; }
  .how-step__mock { grid-column: 1 / -1; }
  .how__spine { left: 21px; }
  .how-step__node { width: 44px; height: 44px; }
  .how-step__node .num { font-size: 19px; }
}