/* ============================================================
   Homeworks — Apple-Inspired Landing Page
   Vanilla CSS · light-first · supports prefers-color-scheme dark
   Spring curve: cubic-bezier(.16, 1, .3, 1) — Apple no-overshoot
   ============================================================ */

/* -------- Tokens (reuse app.css tokens where possible) -------- */
:root {
  /* Re-declared so landing.css is self-contained when loaded standalone */
  --bg: #f5f5f7;
  --surface: rgba(255, 255, 255, 0.72);
  --surface-elevated: rgba(255, 255, 255, 0.92);
  --text: #1d1d1f;
  --text-muted: #86868b;
  --text-subtle: #a1a1a6;
  --accent: #0066CC;
  --accent-hover: #0056b3;
  --accent-glow: rgba(0, 102, 204, 0.28);
  --accent-light: rgba(0, 102, 204, 0.08);
  --border: rgba(0, 0, 0, 0.08);

  /* Landing-only tokens */
  --landing-bg: #f5f5f7;
  --landing-bg-warm: #fafafa;
  --landing-zinc-950: #09090b;
  --landing-zinc-900: #18181b;
  --landing-zinc-800: #27272a;
  --landing-zinc-700: #3f3f46;
  --landing-zinc-600: #52525b;
  --landing-zinc-500: #71717a;
  --landing-zinc-400: #a1a1aa;
  --landing-zinc-300: #d4d4d8;
  --landing-zinc-200: #e4e4e7;
  --landing-zinc-100: #f4f4f5;
  --landing-blue-600: #2563eb;
  --landing-blue-500: #3b82f6;
  --landing-blue-400: #60a5fa;
  --landing-cyan-300: #67e8f9;
  --landing-cyan-200: #a5f3fc;
  --landing-emerald-700: #047857;
  --landing-emerald-50: #ecfdf5;
  --landing-fuchsia-500: #d946ef;
  --landing-indigo-500: #6366f1;
  --landing-card: #ffffff;
  --landing-card-tinted: #fafbff;
  --landing-ring: rgba(228, 228, 231, 0.7);
  --landing-shadow-card: 0 20px 70px rgba(15, 23, 42, 0.08);
  --landing-shadow-card-hover: 0 30px 90px rgba(15, 23, 42, 0.14);
  --landing-shadow-deep: 0 50px 140px rgba(0, 0, 0, 0.62);
  --landing-shadow-soft: 0 1px 4px rgba(0, 0, 0, 0.04);

  --landing-spring: cubic-bezier(.16, 1, .3, 1);
  --landing-dur-md: 480ms;
  --landing-dur-lg: 1050ms;
}

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

html, body { margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body.landing-body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter", "Segoe UI", Roboto, sans-serif;
  font-size: 15px;
  line-height: 1.5;
  color: var(--landing-zinc-950);
  background: var(--landing-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

body.landing-body ::selection {
  background: rgba(191, 219, 254, 0.7);
  color: var(--landing-zinc-950);
}

a { color: inherit; text-decoration: none; }

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  border: none;
  background: transparent;
  color: inherit;
}

img, svg { display: block; max-width: 100%; }

/* Skip link */
.skip-link {
  position: absolute;
  left: 12px;
  top: -40px;
  background: var(--landing-zinc-950);
  color: white;
  padding: 8px 16px;
  border-radius: 999px;
  font-size: 13px;
  z-index: 100;
  transition: top 200ms var(--landing-spring);
}
.skip-link:focus { top: 12px; outline: 2px solid var(--landing-blue-500); }

/* Focus rings */
:focus-visible {
  outline: 2px solid var(--landing-blue-500);
  outline-offset: 3px;
  border-radius: 6px;
}

/* -------- Header / Nav -------- */
.landing-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(40px) saturate(180%);
  -webkit-backdrop-filter: blur(40px) saturate(180%);
}
@supports (backdrop-filter: blur(40px)) {
  .landing-header { background: rgba(255, 255, 255, 0.64); }
}

.landing-nav {
  margin: 0 auto;
  max-width: 1280px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  gap: 16px;
}
@media (min-width: 640px) { .landing-nav { padding: 0 24px; } }
@media (min-width: 1024px) { .landing-nav { padding: 0 32px; } }

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--landing-zinc-950);
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 999px;
  background: var(--landing-zinc-950);
  color: white;
  box-shadow: var(--landing-shadow-soft);
}

.nav-links {
  display: none;
  align-items: center;
  gap: 28px;
}
@media (min-width: 768px) { .nav-links { display: flex; } }

.nav-link {
  font-size: 12px;
  font-weight: 500;
  color: var(--landing-zinc-600);
  transition: color 200ms var(--landing-spring);
}
.nav-link:hover { color: var(--landing-zinc-950); }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.lang-toggle {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--landing-zinc-200);
  background: rgba(255, 255, 255, 0.7);
  padding: 2px;
  border-radius: 999px;
  box-shadow: var(--landing-shadow-soft);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.theme-toggle {
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 999px;
  border: 1px solid var(--landing-zinc-200);
  background: rgba(255, 255, 255, 0.7);
  font-size: 14px;
  cursor: pointer;
  box-shadow: var(--landing-shadow-soft);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  transition: transform 0.15s ease, background 0.15s ease;
}
.theme-toggle:hover { transform: scale(1.05); }
.theme-toggle:focus-visible { outline: 2px solid var(--landing-blue-600); outline-offset: 2px; }
[data-theme="dark"] .theme-toggle {
  background: rgba(24, 24, 27, 0.85);
  border-color: rgba(63, 63, 70, 0.6);
}

.lang-pill {
  padding: 4px 12px;
  font-size: 11px;
  font-weight: 600;
  border-radius: 999px;
  color: var(--landing-zinc-500);
  transition: all 200ms var(--landing-spring);
}
.lang-pill:hover { color: var(--landing-zinc-950); }
.lang-pill.is-active {
  background: var(--landing-zinc-950);
  color: white;
  box-shadow: var(--landing-shadow-soft);
}

.btn-primary-pill {
  display: none;
  align-items: center;
  border-radius: 999px;
  background: var(--landing-zinc-950);
  color: white;
  padding: 6px 16px;
  font-size: 12px;
  font-weight: 500;
  transition: background 200ms var(--landing-spring), transform 200ms var(--landing-spring);
}
.btn-primary-pill:hover { background: var(--landing-zinc-800); transform: translateY(-1px); }
@media (min-width: 640px) { .btn-primary-pill { display: inline-flex; } }

/* -------- Hero -------- */
.hero-section {
  position: relative;
  overflow: hidden;
  padding: 64px 16px 56px;
  min-height: 92vh;
}
@media (min-width: 640px) { .hero-section { padding: 88px 24px 64px; } }
@media (min-width: 1024px) { .hero-section { padding: 96px 32px 64px; } }

.hero-bg-glow {
  position: absolute;
  left: 50%;
  top: 0;
  width: 1100px;
  height: 620px;
  max-width: 140vw;
  transform: translateX(-50%);
  border-radius: 999px;
  background: radial-gradient(circle, #dbeafe 0%, #ede9fe 35%, transparent 70%);
  filter: blur(40px);
  pointer-events: none;
}

.hero-bg-fade {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 176px;
  background: linear-gradient(to top, var(--landing-bg), transparent);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
  margin: 0 auto;
  max-width: 1152px;
  text-align: center;
  will-change: transform, opacity;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 auto 20px;
  padding: 8px 16px;
  border-radius: 999px;
  border: 1px solid var(--landing-zinc-200);
  background: rgba(255, 255, 255, 0.7);
  font-size: 14px;
  font-weight: 500;
  color: var(--landing-zinc-700);
  box-shadow: var(--landing-shadow-soft);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.hero-title {
  margin: 0 auto;
  max-width: 1080px;
  font-size: clamp(36px, 6vw, 72px);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.05;
  color: var(--landing-zinc-950);
}

.hero-text {
  margin: 28px auto 0;
  max-width: 720px;
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.65;
  color: var(--landing-zinc-600);
}

.hero-ctas {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-top: 32px;
}
@media (min-width: 640px) { .hero-ctas { flex-direction: row; } }

.btn-blue,
.btn-white-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 48px;
  padding: 0 28px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  transition: all 220ms var(--landing-spring);
  white-space: nowrap;
}
.btn-blue {
  background: var(--landing-blue-600);
  color: white;
  box-shadow: 0 10px 30px rgba(37, 99, 235, 0.22);
}
.btn-blue:hover { background: var(--landing-blue-500); transform: scale(1.045); }
.btn-blue:active { transform: scale(0.98); }

.btn-white-outline {
  background: white;
  color: var(--landing-blue-600);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
  border: 1px solid var(--landing-zinc-200);
}
.btn-white-outline:hover { background: #f9fafb; transform: scale(1.045); }
.btn-white-outline:active { transform: scale(0.98); }

.hero-stats {
  display: grid;
  gap: 14px;
  margin: 36px auto 0;
  max-width: 880px;
  align-items: stretch;
}
@media (min-width: 640px) {
  .hero-stats {
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin-top: 44px;
  }
}

.stat-card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  height: 100%;
  min-height: 96px;
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.72);
  padding: 18px 20px;
  box-shadow: var(--landing-shadow-soft);
  border: 1px solid var(--landing-ring);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  text-align: left;
}

.stat-value {
  font-size: clamp(20px, 2.4vw, 26px);
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.15;
  color: var(--landing-zinc-950);
  word-break: normal;
  overflow-wrap: break-word;
}
.stat-label {
  margin-top: 0;
  font-size: 13.5px;
  font-weight: 500;
  line-height: 1.4;
  color: var(--landing-zinc-500);
  word-break: normal;
  overflow-wrap: break-word;
}

/* -------- Floating cubes -------- */
.floating-cube {
  position: absolute;
  pointer-events: none;
  display: none;
  opacity: 0;
  transform: scale(0.75);
  animation: cube-enter 1.2s var(--landing-spring) forwards;
}
.floating-cube[data-float-delay="0.55"] { animation-delay: 0.55s; }
.floating-cube[data-float-delay="0.8"]  { animation-delay: 0.8s; }
.floating-cube[data-float-delay="1.05"] { animation-delay: 1.05s; }

@keyframes cube-enter {
  to { opacity: 1; transform: scale(1); }
}

.floating-cube--left  { left: 7%; top: 20%; }
.floating-cube--right { right: 8%; top: 16%; }
.floating-cube--bottom { bottom: 14%; right: 18%; }

@media (min-width: 1024px) {
  .floating-cube--left,
  .floating-cube--right { display: block; }
}
@media (min-width: 1280px) {
  .floating-cube--bottom { display: block; }
}

.glass-cube {
  position: relative;
  width: 112px;
  height: 112px;
  padding: 16px;
  border-radius: 32px;
  border: 1px solid rgba(255, 255, 255, 0.3);
  background: rgba(255, 255, 255, 0.2);
  box-shadow: 0 30px 80px rgba(15, 23, 42, 0.22);
  backdrop-filter: blur(24px) saturate(180%);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  overflow: hidden;
  animation: cube-bobble 6.5s ease-in-out infinite;
}
.floating-cube[data-float-delay="0.55"] .glass-cube { animation-delay: 0.55s; }
.floating-cube[data-float-delay="0.8"]  .glass-cube { animation-delay: 0.8s; }
.floating-cube[data-float-delay="1.05"] .glass-cube { animation-delay: 1.05s; }

@keyframes cube-bobble {
  0%, 100% { transform: translateY(0) rotateZ(0deg); }
  50%      { transform: translateY(-16px) rotateZ(3deg); }
}

.glass-cube__tint {
  position: absolute;
  inset: 0;
  border-radius: 32px;
  pointer-events: none;
}
.glass-cube--blue .glass-cube__tint    { background: linear-gradient(to bottom right, rgba(96, 165, 250, 0.5), rgba(34, 211, 238, 0.2)); }
.glass-cube--fuchsia .glass-cube__tint { background: linear-gradient(to bottom right, rgba(217, 70, 239, 0.45), rgba(99, 102, 241, 0.2)); }
.glass-cube--emerald .glass-cube__tint { background: linear-gradient(to bottom right, rgba(52, 211, 153, 0.45), rgba(34, 211, 238, 0.2)); }

.glass-cube__icon {
  position: relative;
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.85);
  color: var(--landing-zinc-950);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.15);
}

.glass-cube__label {
  position: relative;
  margin: 16px 0 0;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: white;
  text-transform: uppercase;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
}

/* -------- Section primitives -------- */
.section-inner {
  margin: 0 auto;
  max-width: 1280px;
  padding: 0 16px;
}
@media (min-width: 640px) { .section-inner { padding: 0 24px; } }
@media (min-width: 1024px) { .section-inner { padding: 0 32px; } }

.eyebrow {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  margin: 0;
}
.eyebrow--blue { color: var(--landing-blue-600); }
.eyebrow--cyan { color: var(--landing-cyan-300); }

.section-title {
  margin: 12px 0 0;
  max-width: 880px;
  font-size: clamp(28px, 4vw, 48px);
  font-weight: 600;
  letter-spacing: -0.018em;
  line-height: 1.1;
  color: var(--landing-zinc-950);
}
.section-title--inverse { color: white; }
.section-title--centered { margin-left: auto; margin-right: auto; text-align: center; }

.section-lead {
  max-width: 600px;
  font-size: 16px;
  line-height: 1.75;
  color: var(--landing-zinc-600);
  margin: 0;
}
.section-lead--inverse { color: rgba(255, 255, 255, 0.72); margin-top: 24px; }

/* -------- Overview -------- */
.overview-section { padding: 72px 0 80px; }
@media (min-width: 768px) { .overview-section { padding: 80px 0 88px; } }

.section-head--split {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-bottom: 40px;
}
@media (min-width: 1024px) {
  .section-head--split {
    flex-direction: row;
    align-items: flex-end;
    justify-content: space-between;
  }
}

.feature-grid {
  display: grid;
  gap: 20px;
}
@media (min-width: 768px) { .feature-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1024px) { .feature-grid { grid-template-columns: repeat(4, 1fr); } }

.feature-card {
  border-radius: 32px;
  background: var(--landing-card);
  padding: 28px;
  box-shadow: var(--landing-shadow-card);
  border: 1px solid var(--landing-ring);
  transition: transform 350ms var(--landing-spring), box-shadow 350ms var(--landing-spring);
}
.feature-card:hover {
  transform: translateY(-8px) scale(1.025);
  box-shadow: var(--landing-shadow-card-hover);
}

.feature-icon {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: 16px;
  background: var(--landing-zinc-950);
  color: white;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.18);
  margin-bottom: 28px;
  transition: transform 350ms var(--landing-spring);
}
.feature-card:hover .feature-icon { transform: rotate(6deg) scale(1.08); }

.feature-title {
  margin: 0;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.25;
  color: var(--landing-zinc-950);
}
.feature-body {
  margin: 10px 0 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--landing-zinc-600);
}

/* -------- Preview (dark) -------- */
.preview-section {
  position: relative;
  overflow: hidden;
  background: var(--landing-zinc-950);
  color: white;
  padding: 80px 0;
}
@media (min-width: 768px) { .preview-section { padding: 88px 0; } }

.preview-glow {
  position: absolute;
  width: 384px;
  height: 384px;
  border-radius: 999px;
  filter: blur(60px);
  pointer-events: none;
}
.preview-glow--blue   { left: -160px; top: 80px; background: rgba(37, 99, 235, 0.20); }
.preview-glow--fuchsia { right: -160px; bottom: 80px; background: rgba(217, 70, 239, 0.18); }

.preview-grid {
  position: relative;
  display: grid;
  gap: 56px;
  align-items: center;
}
@media (min-width: 1024px) {
  .preview-grid { grid-template-columns: 0.95fr 1.05fr; }
}

.lesson-panel-list {
  display: grid;
  gap: 12px;
  margin-top: 32px;
}

.lesson-panel {
  width: 100%;
  text-align: left;
  border-radius: 22px;
  border: 1px solid rgba(255, 255, 255, 0.10);
  background: rgba(255, 255, 255, 0.05);
  color: white;
  padding: 16px;
  transition:
    transform 280ms var(--landing-spring),
    background 280ms var(--landing-spring),
    border-color 280ms var(--landing-spring),
    color 280ms var(--landing-spring);
}
.lesson-panel:hover {
  background: rgba(255, 255, 255, 0.10);
  transform: translateX(5px) scale(1.018);
}
.lesson-panel:active { transform: translateX(5px) scale(0.985); }

.lesson-panel.is-active {
  background: white;
  color: var(--landing-zinc-950);
  border-color: rgba(255, 255, 255, 0.30);
}

.lesson-panel__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.lesson-panel__eyebrow {
  margin: 0;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.45);
  transition: color 280ms var(--landing-spring);
}
.lesson-panel.is-active .lesson-panel__eyebrow { color: var(--landing-blue-600); }

.lesson-panel__title {
  margin: 4px 0 0;
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.lesson-panel__chev {
  flex-shrink: 0;
  display: grid;
  place-items: center;
  transition: transform 280ms var(--landing-spring);
}
.lesson-panel:hover .lesson-panel__chev { transform: translateX(4px); }

/* -------- Phone mockup -------- */
.phone-stage {
  position: relative;
  margin: 0 auto;
  width: min(280px, 78vw);
  max-width: 390px;
}
@media (min-width: 640px) { .phone-stage { width: min(340px, 60vw); } }
@media (min-width: 1024px) { .phone-stage { width: 390px; } }

.phone-glow {
  position: absolute;
  inset: -48px;
  border-radius: 64px;
  background: linear-gradient(to bottom, rgba(34, 211, 238, 0.35), rgba(99, 102, 241, 0.25), rgba(217, 70, 239, 0.20));
  filter: blur(48px);
  pointer-events: none;
}

.phone-frame {
  position: relative;
  aspect-ratio: 9 / 19.5;
  border-radius: 51px;
  border: 1px solid rgba(255, 255, 255, 0.20);
  background: var(--landing-zinc-950);
  padding: 12px;
  box-shadow: var(--landing-shadow-deep);
  animation: phone-float 8s ease-in-out infinite;
}

@keyframes phone-float {
  0%, 100% { transform: translateY(0) rotateY(-3deg); }
  50%      { transform: translateY(-10px) rotateY(3deg); }
}

.phone-screen {
  height: 100%;
  overflow: hidden;
  border-radius: 39px;
  border: 1px solid rgba(255, 255, 255, 0.10);
  background: #f5f5f7;
  color: var(--landing-zinc-950);
}

.phone-notch {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 32px;
  background: var(--landing-zinc-950);
}
.phone-notch__pill {
  display: block;
  width: 80px;
  height: 6px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.20);
}

.phone-screen-inner {
  position: relative;
  height: 100%;
  min-height: 0;
  overflow: hidden;
  padding: 20px;
  background: radial-gradient(circle at 50% 0%, #ffffff 0%, #eef4ff 40%, #f6f6f6 100%);
}

.phone-content { position: relative; z-index: 1; }

.phone-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}
.phone-header__eyebrow {
  margin: 0;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--landing-zinc-500);
}
.phone-header__subject {
  margin: 4px 0 0;
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.015em;
}
.phone-header__icon {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 999px;
  background: var(--landing-zinc-950);
  color: white;
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.25);
}

.phone-lesson-card {
  border-radius: 32px;
  background: var(--landing-zinc-950);
  padding: 4px;
  color: white;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.4);
  view-transition-name: phone-lesson-card;
}

.phone-lesson-card__inner {
  border-radius: 27px;
  background: linear-gradient(145deg, #111827, #312e81 45%, #020617);
  padding: 20px;
}

.phone-lesson-card__eyebrow {
  margin: 0 0 12px;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--landing-cyan-200);
}

.phone-lesson-card__title {
  margin: 0;
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.2;
}

.phone-lesson-card__body {
  margin: 16px 0 0;
  font-size: 14px;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.7);
}

.phone-lesson-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 28px;
}

.pill {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  border: 1px solid;
  padding: 4px 12px;
  font-size: 12px;
  font-weight: 500;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}
.pill--dark {
  border-color: rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.10);
  color: rgba(255, 255, 255, 0.85);
}

.phone-chev {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 999px;
  background: white;
  color: var(--landing-zinc-950);
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.18);
  transition: transform 220ms var(--landing-spring);
}
.phone-chev:hover { transform: scale(1.08); }
.phone-chev:active { transform: scale(0.95); }

.phone-checkpoint {
  margin-top: 20px;
  border-radius: 28px;
  border: 1px solid var(--landing-zinc-200);
  background: white;
  padding: 16px;
  box-shadow: var(--landing-shadow-soft);
}
.phone-checkpoint__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}
.phone-checkpoint__title {
  margin: 0;
  font-size: 14px;
  font-weight: 500;
}
.phone-checkpoint__chip {
  border-radius: 999px;
  background: var(--landing-emerald-50);
  color: var(--landing-emerald-700);
  padding: 4px 8px;
  font-size: 11px;
  font-weight: 500;
}
.phone-checkpoint__question {
  border-radius: 16px;
  background: var(--landing-zinc-100);
  padding: 12px;
  font-size: 14px;
  color: var(--landing-zinc-600);
  line-height: 1.5;
}
.phone-checkpoint__placeholder {
  margin-top: 12px;
  height: 44px;
  border-radius: 16px;
  border: 1px solid var(--landing-zinc-200);
  background: white;
  padding: 12px 16px;
  font-size: 12px;
  color: var(--landing-zinc-400);
}

.phone-foot {
  position: absolute;
  left: 20px;
  right: 20px;
  bottom: 20px;
  z-index: 1;
}
.phone-dots {
  display: flex;
  justify-content: center;
  gap: 6px;
  margin-bottom: 12px;
}
.phone-dot {
  display: block;
  height: 6px;
  width: 6px;
  border-radius: 999px;
  background: var(--landing-zinc-300);
  transition: width 360ms var(--landing-spring), background 360ms var(--landing-spring);
}
.phone-dot.is-active {
  width: 32px;
  background: var(--landing-zinc-950);
}

.phone-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 48px;
  width: 100%;
  border-radius: 999px;
  background: var(--landing-zinc-950);
  color: white;
  font-size: 14px;
  font-weight: 500;
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.25);
  transition: transform 220ms var(--landing-spring);
}
.phone-cta:hover { transform: scale(1.02); }
.phone-cta:active { transform: scale(0.98); }

/* View Transition styling for the phone lesson card swap */
::view-transition-old(phone-lesson-card),
::view-transition-new(phone-lesson-card) {
  animation-duration: var(--landing-dur-md);
  animation-timing-function: var(--landing-spring);
}

/* -------- Tutor section -------- */
.tutor-section { padding: 96px 0; }

.tutor-grid {
  display: grid;
  gap: 24px;
}
@media (min-width: 1024px) { .tutor-grid { grid-template-columns: 2fr 1fr; } }

.tutor-card-dark {
  position: relative;
  overflow: hidden;
  border-radius: 40px;
  background: var(--landing-zinc-950);
  color: white;
  padding: 32px;
  box-shadow: 0 25px 70px rgba(0, 0, 0, 0.4);
}
@media (min-width: 1024px) { .tutor-card-dark { padding: 48px; } }

.tutor-card-dark__glow {
  position: absolute;
  right: -18%;
  top: -20%;
  width: 320px;
  height: 320px;
  border-radius: 999px;
  background: rgba(34, 211, 238, 0.20);
  filter: blur(60px);
  pointer-events: none;
}

.tutor-card-dark__head {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 48px;
}
.tutor-card-dark__brain { color: var(--landing-cyan-300); }

.tutor-card-dark__title {
  position: relative;
  margin: 0;
  max-width: 880px;
  font-size: clamp(28px, 4vw, 48px);
  font-weight: 600;
  letter-spacing: -0.018em;
  line-height: 1.1;
}

.tutor-chat {
  position: relative;
  margin-top: 40px;
  display: grid;
  gap: 16px;
}
@media (min-width: 768px) { .tutor-chat { grid-template-columns: repeat(2, 1fr); } }

.tutor-chat__bubble {
  border-radius: 26px;
  padding: 20px;
}
.tutor-chat__bubble--student {
  background: rgba(255, 255, 255, 0.10);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}
.tutor-chat__bubble--tutor {
  background: white;
  color: var(--landing-zinc-950);
}

.tutor-chat__role {
  margin: 0;
  font-size: 14px;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.55);
}
.tutor-chat__role--accent { color: var(--landing-blue-600); }
.tutor-chat__msg {
  margin: 8px 0 0;
  font-size: 16px;
  font-weight: 500;
  line-height: 1.5;
}

.tutor-card-light {
  border-radius: 40px;
  background: white;
  padding: 32px;
  box-shadow: var(--landing-shadow-card);
  border: 1px solid var(--landing-zinc-200);
  transition: transform 350ms var(--landing-spring), box-shadow 350ms var(--landing-spring);
}
@media (min-width: 1024px) { .tutor-card-light { padding: 40px; } }
.tutor-card-light:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: var(--landing-shadow-card-hover);
}

.tutor-card-light__icon {
  display: grid;
  place-items: center;
  width: 56px;
  height: 56px;
  border-radius: 16px;
  background: var(--landing-emerald-50);
  color: var(--landing-emerald-700);
}
.tutor-card-light__title {
  margin: 32px 0 0;
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--landing-zinc-950);
}
.tutor-card-light__body {
  margin: 16px 0 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--landing-zinc-600);
}

/* -------- Workflow -------- */
.workflow-section { padding: 0 0 96px; }

.workflow-shell {
  margin: 0 auto;
  border-radius: 48px;
  background: white;
  padding: 24px;
  box-shadow: 0 24px 90px rgba(15, 23, 42, 0.08);
  border: 1px solid var(--landing-zinc-200);
}
@media (min-width: 640px) { .workflow-shell { padding: 40px; } }
@media (min-width: 1024px) { .workflow-shell { padding: 56px; } }

.workflow-head {
  text-align: center;
  margin-bottom: 48px;
}

.workflow-grid {
  display: grid;
  gap: 16px;
}
@media (min-width: 1024px) { .workflow-grid { grid-template-columns: repeat(4, 1fr); } }

.workflow-step {
  border-radius: 32px;
  background: var(--landing-bg);
  padding: 24px;
  transition: transform 320ms var(--landing-spring);
}
.workflow-step:hover { transform: translateY(-7px) scale(1.02); }

.workflow-step__num {
  margin: 0 0 32px;
  font-size: 14px;
  font-weight: 600;
  color: var(--landing-zinc-400);
  letter-spacing: 0.04em;
}
.workflow-step__title {
  margin: 0;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--landing-zinc-950);
}
.workflow-step__body {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--landing-zinc-600);
}

/* -------- Paired cards -------- */
.paired-cards-section { padding: 0 0 96px; }

.paired-grid {
  display: grid;
  gap: 24px;
}
@media (min-width: 1024px) { .paired-grid { grid-template-columns: repeat(2, 1fr); } }

.quick-card,
.safe-card {
  position: relative;
  overflow: hidden;
  border-radius: 48px;
  padding: 32px;
  transition: transform 350ms var(--landing-spring);
}
@media (min-width: 1024px) {
  .quick-card,
  .safe-card { padding: 48px; }
}
.quick-card:hover,
.safe-card:hover { transform: translateY(-8px) scale(1.018); }

.quick-card {
  background: linear-gradient(145deg, #eff6ff, #ffffff);
  box-shadow: var(--landing-shadow-soft);
  border: 1px solid var(--landing-zinc-200);
}

.quick-card__glow {
  position: absolute;
  right: -64px;
  top: -64px;
  width: 192px;
  height: 192px;
  border-radius: 999px;
  background: rgba(96, 165, 250, 0.20);
  filter: blur(48px);
  pointer-events: none;
}

.quick-card__icon {
  position: relative;
  display: inline-flex;
  color: var(--landing-blue-600);
}

.quick-card__title {
  position: relative;
  margin: 40px 0 0;
  font-size: clamp(28px, 3.5vw, 36px);
  font-weight: 600;
  letter-spacing: -0.018em;
  color: var(--landing-zinc-950);
}

.quick-card__body {
  position: relative;
  margin: 20px 0 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--landing-zinc-600);
}

.safe-card {
  background: linear-gradient(145deg, #111827, #020617);
  color: white;
  box-shadow: 0 25px 70px rgba(0, 0, 0, 0.35);
}

.safe-card__glow {
  position: absolute;
  right: -64px;
  top: -64px;
  width: 192px;
  height: 192px;
  border-radius: 999px;
  background: rgba(34, 211, 238, 0.22);
  filter: blur(48px);
  pointer-events: none;
}

.safe-card__icon {
  position: relative;
  display: inline-flex;
  color: var(--landing-cyan-300);
}

.safe-card__title {
  position: relative;
  margin: 40px 0 0;
  font-size: clamp(28px, 3.5vw, 36px);
  font-weight: 600;
  letter-spacing: -0.018em;
}

.safe-card__body {
  position: relative;
  margin: 20px 0 0;
  font-size: 16px;
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.72);
}

/* -------- Launch -------- */
.launch-section {
  padding: 0 16px 96px;
}
@media (min-width: 640px) { .launch-section { padding: 0 24px 96px; } }
@media (min-width: 1024px) { .launch-section { padding: 0 32px 96px; } }

.launch-shell {
  position: relative;
  margin: 0 auto;
  max-width: 1152px;
  overflow: hidden;
  border-radius: 56px;
  background: var(--landing-zinc-950);
  color: white;
  text-align: center;
  padding: 32px;
  box-shadow: 0 40px 120px rgba(0, 0, 0, 0.35);
}
@media (min-width: 640px) { .launch-shell { padding: 56px; } }
@media (min-width: 1024px) { .launch-shell { padding: 64px; } }

.launch-bg-glow {
  position: absolute;
  left: 50%;
  top: 0;
  width: 384px;
  height: 384px;
  transform: translateX(-50%);
  border-radius: 999px;
  background: rgba(59, 130, 246, 0.20);
  filter: blur(60px);
  pointer-events: none;
}

.launch-floating-icon {
  position: relative;
  display: grid;
  place-items: center;
  width: 64px;
  height: 64px;
  margin: 0 auto 32px;
  border-radius: 24px;
  background: white;
  color: var(--landing-zinc-950);
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.35);
  animation: launch-bobble 6s ease-in-out infinite;
}
@keyframes launch-bobble {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50%      { transform: translateY(-10px) rotate(4deg); }
}

.launch-title {
  position: relative;
  margin: 0 auto;
  max-width: 880px;
  font-size: clamp(28px, 4.5vw, 56px);
  font-weight: 600;
  letter-spacing: -0.018em;
  line-height: 1.08;
}

.launch-text {
  position: relative;
  margin: 28px auto 0;
  max-width: 600px;
  font-size: clamp(15px, 1.5vw, 18px);
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.72);
}

.launch-ctas {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 12px;
  margin-top: 40px;
}
@media (min-width: 640px) { .launch-ctas { flex-direction: row; } }

.btn-white-pill,
.btn-ghost-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 52px;
  padding: 0 32px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  transition: all 220ms var(--landing-spring);
  white-space: nowrap;
}
.btn-white-pill {
  background: white;
  color: var(--landing-zinc-950);
}
.btn-white-pill:hover { background: var(--landing-zinc-200); transform: scale(1.045); }
.btn-white-pill:active { transform: scale(0.98); }

.btn-ghost-outline {
  border: 1px solid rgba(255, 255, 255, 0.20);
  color: white;
}
.btn-ghost-outline:hover { background: rgba(255, 255, 255, 0.10); transform: scale(1.045); }
.btn-ghost-outline:active { transform: scale(0.98); }

/* -------- Footer -------- */
.landing-footer {
  padding: 32px 0 48px;
  font-size: 13px;
  color: var(--landing-zinc-500);
}
.landing-footer__inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}
.landing-footer__sep { color: var(--landing-zinc-300); }

/* -------- Reveal animations (IntersectionObserver) -------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(42px) scale(0.965);
  filter: blur(14px);
  transition:
    opacity var(--landing-dur-lg) var(--landing-spring),
    transform var(--landing-dur-lg) var(--landing-spring),
    filter var(--landing-dur-lg) var(--landing-spring);
  will-change: opacity, transform, filter;
}
[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0) scale(1);
  filter: blur(0);
}

/* Stagger children inside a parent that becomes visible */
.stagger-parent .stagger-child {
  opacity: 0;
  transform: translateY(28px) scale(0.92);
  filter: blur(12px);
  transition:
    opacity 950ms var(--landing-spring),
    transform 950ms var(--landing-spring),
    filter 950ms var(--landing-spring);
  will-change: opacity, transform, filter;
}
.stagger-parent.is-visible .stagger-child { opacity: 1; transform: none; filter: blur(0); }
.stagger-parent.is-visible .stagger-child:nth-child(1) { transition-delay: 120ms; }
.stagger-parent.is-visible .stagger-child:nth-child(2) { transition-delay: 260ms; }
.stagger-parent.is-visible .stagger-child:nth-child(3) { transition-delay: 400ms; }
.stagger-parent.is-visible .stagger-child:nth-child(4) { transition-delay: 540ms; }
.stagger-parent.is-visible .stagger-child:nth-child(5) { transition-delay: 680ms; }

/* Hero content already visible (no scroll trigger needed) but still want the staggered entrance */
.hero-content.is-visible .stagger-child {
  animation: hero-stagger-in 1100ms var(--landing-spring) both;
}
.hero-content.is-visible .stagger-child:nth-child(1) { animation-delay: 80ms; }
.hero-content.is-visible .stagger-child:nth-child(2) { animation-delay: 220ms; }
.hero-content.is-visible .stagger-child:nth-child(3) { animation-delay: 360ms; }
.hero-content.is-visible .stagger-child:nth-child(4) { animation-delay: 500ms; }

@keyframes hero-stagger-in {
  from { opacity: 0; transform: translateY(28px) scale(0.92); filter: blur(12px); }
  to   { opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
}

/* -------- prefers-reduced-motion -------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  [data-reveal],
  .stagger-parent .stagger-child,
  .hero-content.is-visible .stagger-child {
    opacity: 1 !important;
    transform: none !important;
    filter: none !important;
    animation: none !important;
  }
  .floating-cube { opacity: 1 !important; transform: scale(1) !important; }
  .glass-cube,
  .phone-frame,
  .launch-floating-icon { animation: none !important; }
}

/* -------- Responsive tweaks -------- */
@media (max-width: 767px) {
  .hero-title { font-size: clamp(32px, 8vw, 44px); }
  .preview-grid { gap: 40px; }
  .lesson-panel__title { font-size: 16px; }
  .phone-screen-inner { padding: 16px; }
  .phone-foot { left: 16px; right: 16px; bottom: 16px; }
}

/* -------- Dark mode (manual toggle via theme.js — stays in sync with rest of app) -------- */
[data-theme="dark"] {
  --landing-bg: #0a0a0a;
  --landing-bg-warm: #111111;
  --landing-card: #18181b;
  --landing-card-tinted: #1f2026;
  --landing-ring: rgba(63, 63, 70, 0.7);
  --landing-shadow-card: 0 20px 60px rgba(0, 0, 0, 0.4);
  --landing-shadow-card-hover: 0 30px 80px rgba(0, 0, 0, 0.55);
  --landing-shadow-soft: 0 1px 4px rgba(0, 0, 0, 0.35);
}

[data-theme="dark"] body.landing-body {
  color: rgba(244, 244, 245, 0.96);
  background: var(--landing-bg);
}

[data-theme="dark"] body.landing-body ::selection {
  background: rgba(37, 99, 235, 0.4);
  color: white;
}

[data-theme="dark"] .landing-header {
  background: rgba(10, 10, 10, 0.78);
  border-bottom-color: rgba(63, 63, 70, 0.5);
}
@supports (backdrop-filter: blur(40px)) {
  [data-theme="dark"] .landing-header { background: rgba(10, 10, 10, 0.62); }
}

[data-theme="dark"] .brand-link { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .brand-mark { background: white; color: var(--landing-zinc-950); }

[data-theme="dark"] .nav-link { color: rgba(244, 244, 245, 0.62); }
[data-theme="dark"] .nav-link:hover { color: rgba(244, 244, 245, 0.96); }

[data-theme="dark"] .lang-toggle {
  background: rgba(24, 24, 27, 0.85);
  border-color: rgba(63, 63, 70, 0.6);
}
[data-theme="dark"] .lang-pill { color: rgba(244, 244, 245, 0.55); }
[data-theme="dark"] .lang-pill:hover { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .lang-pill.is-active { background: white; color: var(--landing-zinc-950); }

[data-theme="dark"] .btn-primary-pill { background: white; color: var(--landing-zinc-950); }
[data-theme="dark"] .btn-primary-pill:hover { background: rgba(244, 244, 245, 0.85); }

[data-theme="dark"] .hero-bg-glow {
  background: radial-gradient(circle, rgba(37, 99, 235, 0.25) 0%, rgba(99, 102, 241, 0.18) 35%, transparent 70%);
}
[data-theme="dark"] .hero-bg-fade { background: linear-gradient(to top, var(--landing-bg), transparent); }

[data-theme="dark"] .hero-title { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .hero-text { color: rgba(244, 244, 245, 0.72); }

[data-theme="dark"] .hero-badge {
  background: rgba(24, 24, 27, 0.7);
  border-color: rgba(63, 63, 70, 0.6);
  color: rgba(244, 244, 245, 0.85);
}

[data-theme="dark"] .stat-card {
  background: rgba(24, 24, 27, 0.7);
  border-color: rgba(63, 63, 70, 0.6);
}
[data-theme="dark"] .stat-value { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .stat-label { color: rgba(244, 244, 245, 0.62); }

/* Overview / feature cards (light by default → dark in dark mode) */
[data-theme="dark"] .feature-card {
  background: var(--landing-card);
  border-color: var(--landing-ring);
}
[data-theme="dark"] .feature-title { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .feature-body { color: rgba(244, 244, 245, 0.72); }
[data-theme="dark"] .feature-icon { background: white; color: var(--landing-zinc-950); }

[data-theme="dark"] .section-title { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .section-lead { color: rgba(244, 244, 245, 0.72); }

[data-theme="dark"] .eyebrow--blue { color: var(--landing-blue-400); }

/* Tutor light card → dark mode */
[data-theme="dark"] .tutor-card-light {
  background: var(--landing-card);
  border-color: var(--landing-ring);
}
[data-theme="dark"] .tutor-card-light__title { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .tutor-card-light__body { color: rgba(244, 244, 245, 0.72); }

/* Workflow shell */
[data-theme="dark"] .workflow-shell {
  background: var(--landing-card);
  border-color: var(--landing-ring);
}
[data-theme="dark"] .workflow-step { background: rgba(24, 24, 27, 0.6); }
[data-theme="dark"] .workflow-step__title { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .workflow-step__body { color: rgba(244, 244, 245, 0.72); }
[data-theme="dark"] .workflow-step__num { color: rgba(244, 244, 245, 0.45); }

/* Quick card stays light-tinted? — adopt darker gradient */
[data-theme="dark"] .quick-card {
  background: linear-gradient(145deg, #1e293b, #0f172a);
  border-color: rgba(63, 63, 70, 0.6);
  color: rgba(244, 244, 245, 0.96);
}
[data-theme="dark"] .quick-card__icon { color: var(--landing-blue-400); }
[data-theme="dark"] .quick-card__title { color: rgba(244, 244, 245, 0.96); }
[data-theme="dark"] .quick-card__body { color: rgba(244, 244, 245, 0.72); }

/* btn-blue / btn-white-outline tweaks for dark page */
[data-theme="dark"] .btn-white-outline {
  background: var(--landing-card);
  border-color: var(--landing-ring);
  color: var(--landing-blue-400);
}
[data-theme="dark"] .btn-white-outline:hover { background: rgba(39, 39, 42, 0.9); }

[data-theme="dark"] .landing-footer { color: rgba(244, 244, 245, 0.55); }
[data-theme="dark"] .landing-footer__sep { color: rgba(244, 244, 245, 0.30); }

/* dark-section is intentional: always dark regardless of theme */
.dark-section { color: white; }

/* Embedded dark sections get slightly stronger separation against a dark page bg */
[data-theme="dark"] .preview-section { box-shadow: 0 0 0 1px rgba(63, 63, 70, 0.4); }
[data-theme="dark"] .tutor-card-dark,
[data-theme="dark"] .safe-card,
[data-theme="dark"] .launch-shell { box-shadow: 0 25px 70px rgba(0, 0, 0, 0.55), 0 0 0 1px rgba(63, 63, 70, 0.4); }