/* DeepExplain v5 — Premium typography, cinematic aesthetics, luxurious controls */

/* ─── WEB FONTS ─── */
@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:ital,opsz,wght@0,8..60,300;0,8..60,400;0,8..60,500;0,8..60,600;1,8..60,300;1,8..60,400&family=Inter:wght@300;400;500;600&family=JetBrains+Mono:wght@300;400;500&display=swap');

/* ─── BASE ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: 15px;
  scroll-behavior: smooth;
}

body {
  background: #05050b;
  color: #b8bcc8;
  font-family: 'Inter', -apple-system, 'Segoe UI', sans-serif;
  line-height: 1.75;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  letter-spacing: 0.01em;
}

::selection {
  background: rgba(92, 156, 230, 0.25);
  color: #e8eaf6;
}

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: #05050b; }
::-webkit-scrollbar-thumb { background: #1a1a30; border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: #2a2a50; }

/* ─── TOP NAV ─── */
.topnav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.7rem 1.8rem;
  background: rgba(5, 5, 11, 0.92);
  backdrop-filter: blur(20px) saturate(1.2);
  -webkit-backdrop-filter: blur(20px) saturate(1.2);
  border-bottom: 1px solid rgba(92, 156, 230, 0.04);
  font-family: 'Inter', -apple-system, sans-serif;
  font-size: 0.78rem;
  font-weight: 400;
  letter-spacing: 0.01em;
}

.nav-home {
  color: #8899bb;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: color 0.3s;
}
.nav-home:hover { color: #a8c8f0; }
.nav-logo {
  font-size: 1rem;
  color: #5c9ce6;
  font-weight: 500;
  font-family: 'JetBrains Mono', monospace;
}
.accent { color: #5c9ce6; }
.nav-sep { color: #222; }
.nav-current { color: #444; font-weight: 300; }

/* ─── 3D HERO SCENE ─── */
.hero-scene {
  position: relative;
  width: 100%;
  height: 70vh;
  min-height: 480px;
  max-height: 640px;
  overflow: hidden;
  background: radial-gradient(ellipse at 50% 35%, #0c1228 0%, #060610 50%, #03030a 100%);
  border-bottom: 1px solid rgba(92, 156, 230, 0.06);
}

.hero-scene::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 30% 25%, rgba(92, 156, 230, 0.04) 0%, transparent 40%),
    radial-gradient(circle at 70% 60%, rgba(180, 100, 220, 0.03) 0%, transparent 35%);
  pointer-events: none;
  z-index: 1;
}

.hero-scene::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 10%;
  right: 10%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(92, 156, 230, 0.15), transparent);
  z-index: 2;
}

#bloch-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  cursor: grab;
  z-index: 0;
}
#bloch-canvas:active { cursor: grabbing; }

.hero-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 2.5rem 2rem 3.5rem;
  background: linear-gradient(transparent 0%, rgba(5, 5, 11, 0.85) 60%, rgba(5, 5, 11, 0.98) 100%);
  pointer-events: none;
  z-index: 3;
}

.hero-title-wrap {
  max-width: 480px;
  margin: 0 auto;
  text-align: center;
}

.hero-title {
  font-family: 'Inter', sans-serif;
  font-size: 1.15rem;
  font-weight: 500;
  color: #dde0ea;
  letter-spacing: -0.02em;
  line-height: 1.55;
  margin-bottom: 0.4rem;
}

.hero-sub {
  font-family: 'Inter', sans-serif;
  font-size: 0.72rem;
  color: rgba(92, 156, 230, 0.45);
  font-weight: 400;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero-state {
  position: absolute;
  top: 4.5rem;
  left: 50%;
  transform: translateX(-50%);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  font-weight: 300;
  color: rgba(92, 156, 230, 0.55);
  background: rgba(10, 14, 30, 0.5);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  padding: 0.3rem 1rem;
  border-radius: 20px;
  border: 1px solid rgba(92, 156, 230, 0.08);
  text-shadow: 0 0 20px rgba(92, 156, 230, 0.15);
  opacity: 0.9;
  pointer-events: none;
  white-space: nowrap;
  letter-spacing: 0.04em;
  z-index: 4;
}

.scroll-hint {
  position: absolute;
  bottom: 1.2rem;
  left: 50%;
  transform: translateX(-50%);
  animation: bobUpDown 3s infinite ease-in-out;
  z-index: 4;
}

.scroll-arrow {
  width: 14px;
  height: 14px;
  border-right: 1px solid rgba(92, 156, 230, 0.15);
  border-bottom: 1px solid rgba(92, 156, 230, 0.15);
  transform: rotate(45deg);
}

@keyframes bobUpDown {
  0%, 100% { transform: translateX(-50%) translateY(0); opacity: 0.15; }
  50% { transform: translateX(-50%) translateY(6px); opacity: 0.4; }
}

/* ─── 3D INLINE SECTIONS ─── */
.scene-3d {
  position: relative;
  width: calc(100% + 3rem);
  height: 42vh;
  min-height: 340px;
  max-height: 480px;
  margin: 3rem -1.5rem;
  overflow: hidden;
  border-radius: 12px;
  background: radial-gradient(ellipse at 50% 40%, #0a0e22 0%, #060610 60%, #04040c 100%);
  border: 1px solid rgba(92, 156, 230, 0.04);
  box-shadow: 0 4px 40px rgba(0, 0, 0, 0.3), inset 0 1px 0 rgba(92, 156, 230, 0.03);
}

.scene-3d canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  cursor: grab;
}
.scene-3d canvas:active { cursor: grabbing; }

.scene-3d-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 1.5rem 2rem;
  background: linear-gradient(transparent, rgba(5,5,11,0.9));
  pointer-events: none;
}

.scene-3d-label {
  font-family: 'Inter', sans-serif;
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: rgba(92, 156, 230, 0.4);
  font-weight: 500;
}

.scene-3d-readout {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  color: rgba(92, 156, 230, 0.6);
  margin-top: 0.3rem;
  font-weight: 300;
}

/* ─── MAIN CONTENT ─── */
main {
  max-width: 640px;
  margin: 0 auto;
  padding: 5rem 1.5rem 6rem;
}

p {
  margin-bottom: 1.4rem;
  text-align: left;
  text-indent: 0;
  font-size: 0.95rem;
  font-weight: 400;
  line-height: 1.75;
}

p.lead {
  font-size: 1.05rem;
  color: #c8ccd4;
  font-weight: 400;
  line-height: 1.85;
}

em { color: #88b0d8; font-style: italic; }
strong { color: #d0d0d8; font-weight: 500; }

h2.section-break {
  font-family: 'Inter', sans-serif;
  font-size: 1.1rem;
  font-weight: 600;
  color: #c0c8d8;
  margin: 3.5rem 0 2rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid rgba(92, 156, 230, 0.06);
  letter-spacing: 0.01em;
}

.aside-note {
  margin: 2rem 0;
  padding: 1rem 1.3rem;
  border-left: 2px solid rgba(92, 156, 230, 0.15);
  background: rgba(92, 156, 230, 0.02);
  border-radius: 0 10px 10px 0;
  font-size: 0.82rem;
  color: #7888a0;
  font-style: normal;
  line-height: 1.7;
}

p.closing {
  text-align: center;
  color: #2a2a40;
  font-size: 0.72rem;
  margin-top: 6rem;
  font-family: 'Inter', sans-serif;
  font-weight: 300;
}
p.closing a { color: rgba(92,156,230,0.5); text-decoration: none; }
p.closing a:hover { color: #7bbef7; }

/* KaTeX overrides */
.katex { color: #c0d0e8; font-size: 1em; }
.katex-display { margin: 2.2rem 0; }
.katex-display > .katex { font-size: 1.08em; }

/* ─── INTERACTIVE CONTAINERS ─── */
.interactive {
  margin: 3rem -0.5rem 3.5rem;
  padding: 2rem;
  background: linear-gradient(180deg, #080814 0%, #06060e 100%);
  border-radius: 16px;
  border: 1px solid rgba(92, 156, 230, 0.06);
  position: relative;
  transition: border-color 0.5s ease, box-shadow 0.5s ease;
}

.interactive:hover {
  border-color: rgba(92, 156, 230, 0.14);
  box-shadow: 0 0 80px -30px rgba(92, 156, 230, 0.06);
}

.glow-border {
  box-shadow: 0 0 0 1px rgba(92, 156, 230, 0.02);
  animation: subtleGlow 10s infinite ease-in-out alternate;
}

@keyframes subtleGlow {
  0% { box-shadow: 0 0 0 1px rgba(92,156,230,0.02), 0 0 40px -20px rgba(92,156,230,0.02); }
  100% { box-shadow: 0 0 0 1px rgba(92,156,230,0.05), 0 0 60px -20px rgba(92,156,230,0.06); }
}

.interactive-label {
  position: absolute;
  top: -0.5rem;
  left: 1.5rem;
  background: #080814;
  padding: 0 0.6rem;
  font-family: 'Inter', sans-serif;
  font-size: 0.58rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(92, 156, 230, 0.35);
  font-weight: 500;
}

/* ─── CONTROLS (premium sliders) ─── */
.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  margin-bottom: 1.2rem;
  font-family: 'Inter', sans-serif;
}

.ctrl {
  flex: 1;
  min-width: 200px;
}
.ctrl label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  color: #445566;
  margin-bottom: 0.6rem;
  font-size: 0.68rem;
  font-weight: 400;
  letter-spacing: 0.03em;
}
.val {
  color: rgba(92, 156, 230, 0.6);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.65rem;
  font-weight: 300;
}

/* Premium range slider */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, rgba(92,156,230,0.06), rgba(92,156,230,0.12), rgba(92,156,230,0.06));
  border-radius: 1px;
  outline: none;
  cursor: pointer;
  margin: 0.6rem 0;
  position: relative;
}
input[type="range"]::-webkit-slider-runnable-track {
  height: 1px;
  border-radius: 1px;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  background: radial-gradient(circle at 40% 35%, #a0d0f0, #4a88c8);
  border-radius: 50%;
  cursor: pointer;
  border: 2.5px solid #0a0a18;
  box-shadow:
    0 0 0 2px rgba(92, 156, 230, 0.06),
    0 0 20px rgba(92, 156, 230, 0.12),
    0 1px 6px rgba(0, 0, 0, 0.4);
  transition: box-shadow 0.4s ease, transform 0.3s ease;
  margin-top: -8px;
}
input[type="range"]::-webkit-slider-thumb:hover {
  box-shadow:
    0 0 0 4px rgba(92, 156, 230, 0.1),
    0 0 30px rgba(92, 156, 230, 0.2),
    0 1px 8px rgba(0, 0, 0, 0.5);
  transform: scale(1.12);
}
input[type="range"]::-webkit-slider-thumb:active {
  transform: scale(1.05);
  box-shadow:
    0 0 0 5px rgba(92, 156, 230, 0.12),
    0 0 35px rgba(92, 156, 230, 0.25),
    0 1px 10px rgba(0, 0, 0, 0.5);
}
input[type="range"]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  background: radial-gradient(circle at 40% 35%, #a0d0f0, #4a88c8);
  border-radius: 50%;
  cursor: pointer;
  border: 2.5px solid #0a0a18;
  box-shadow: 0 0 20px rgba(92, 156, 230, 0.12);
}

.btn-row {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  width: 100%;
}
.btn {
  background: transparent;
  border: 1px solid rgba(92, 156, 230, 0.08);
  color: #556677;
  padding: 0.4rem 1rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.7rem;
  font-family: 'JetBrains Mono', monospace;
  font-weight: 400;
  transition: all 0.4s ease;
  letter-spacing: 0.02em;
}
.btn:hover {
  border-color: rgba(92, 156, 230, 0.2);
  color: #8ab0d8;
  background: rgba(92, 156, 230, 0.04);
}
.btn.active {
  background: rgba(92, 156, 230, 0.08);
  border-color: rgba(92, 156, 230, 0.2);
  color: #7bb8f0;
  box-shadow: 0 0 20px rgba(92, 156, 230, 0.06);
}

/* ─── VIZ & READOUT ─── */
.viz {
  width: 100%;
  border-radius: 10px;
  overflow: hidden;
  margin-bottom: 1rem;
  position: relative;
  background: rgba(5, 5, 11, 0.4);
}

.viz::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 10px;
  pointer-events: none;
  border: 1px solid transparent;
  animation: vizPulse 8s infinite ease-in-out;
}

@keyframes vizPulse {
  0%, 100% { border-color: rgba(92, 156, 230, 0.0); }
  50% { border-color: rgba(92, 156, 230, 0.04); }
}

.state-readout {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  font-weight: 300;
  color: rgba(92, 156, 230, 0.6);
  text-align: center;
  margin-bottom: 1rem;
  padding: 0.7rem;
  background: rgba(92, 156, 230, 0.02);
  border-radius: 8px;
  border: 1px solid rgba(92, 156, 230, 0.04);
  letter-spacing: 0.03em;
}

.readout {
  font-family: 'Inter', sans-serif;
  font-size: 0.72rem;
}
.output-row {
  display: flex;
  justify-content: space-between;
  padding: 0.35rem 0;
  border-bottom: 1px solid rgba(255,255,255,0.015);
}
.output-row:last-child { border-bottom: none; }
.output-label { color: #3a4a5a; font-weight: 400; }
.output-value {
  color: rgba(140, 180, 220, 0.7);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.68rem;
  font-weight: 300;
}

/* ─── EXERCISES ─── */
.exercises {
  margin-top: 4rem;
}
.exercise {
  background: linear-gradient(180deg, #080814 0%, #06060e 100%);
  border: 1px solid rgba(92, 156, 230, 0.04);
  border-radius: 14px;
  padding: 1.5rem 1.8rem;
  margin-bottom: 1rem;
}
.exercise p {
  margin-bottom: 0.8rem;
  font-size: 0.88rem;
  font-weight: 400;
}
.exercise input[type="text"] {
  width: calc(100% - 90px);
  background: rgba(5, 5, 11, 0.6);
  border: 1px solid rgba(92, 156, 230, 0.08);
  border-radius: 8px;
  padding: 0.5rem 0.8rem;
  color: #a8a8bc;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  font-weight: 300;
  margin-right: 0.5rem;
  outline: none;
  transition: border-color 0.4s, box-shadow 0.4s;
}
.exercise input[type="text"]:focus {
  border-color: rgba(92, 156, 230, 0.2);
  box-shadow: 0 0 25px rgba(92, 156, 230, 0.06);
}
.feedback { margin-top: 0.6rem; font-size: 0.78rem; font-family: 'Inter', sans-serif; font-weight: 400; }
.feedback.correct { color: #66bb6a; }
.feedback.wrong { color: #e07070; }

/* ─── LANDING PAGE ─── */
.home {
  max-width: 700px;
  margin: 0 auto;
  padding: 6rem 1.5rem 4rem;
  min-height: 100vh;
}

.home-hero {
  text-align: center;
  margin-bottom: 4rem;
}

.hero-mark {
  font-size: 2.8rem;
  font-weight: 400;
  color: rgba(92, 156, 230, 0.7);
  text-shadow: 0 0 60px rgba(92, 156, 230, 0.12);
  letter-spacing: 0.08em;
  font-family: 'JetBrains Mono', monospace;
  animation: markPulse 5s infinite ease-in-out;
}

@keyframes markPulse {
  0%, 100% { text-shadow: 0 0 50px rgba(92,156,230,0.06); opacity: 0.8; }
  50% { text-shadow: 0 0 70px rgba(92,156,230,0.18); opacity: 1; }
}

.logo-text {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 2.2rem;
  font-weight: 500;
  color: #c8ccd8;
  letter-spacing: -0.02em;
  margin-top: 0.6rem;
}

.tagline {
  color: #3a4a5a;
  font-size: 0.92rem;
  font-family: 'Source Serif 4', Georgia, serif;
  font-weight: 300;
  margin-top: 0.6rem;
  line-height: 1.7;
}

.article-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.article-card {
  display: block;
  text-decoration: none;
  background: linear-gradient(180deg, #080814 0%, #06060e 100%);
  border: 1px solid rgba(92, 156, 230, 0.05);
  border-radius: 14px;
  padding: 1.8rem 2rem;
  transition: all 0.5s ease;
  position: relative;
  overflow: hidden;
}

.article-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(92,156,230,0.25), transparent);
  opacity: 0;
  transition: opacity 0.5s;
}

.article-card:hover {
  border-color: rgba(92, 156, 230, 0.12);
  transform: translateY(-1px);
  box-shadow: 0 15px 50px -20px rgba(92, 156, 230, 0.08);
}
.article-card:hover::before { opacity: 1; }

.card-meta {
  font-family: 'Inter', sans-serif;
  font-size: 0.6rem;
  color: rgba(92, 156, 230, 0.35);
  margin-bottom: 0.6rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-weight: 500;
}

.card-title {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 1.12rem;
  font-weight: 500;
  color: #b8c0d0;
  margin-bottom: 0.5rem;
}

.card-desc {
  color: #445566;
  font-size: 0.8rem;
  line-height: 1.7;
  font-family: 'Inter', sans-serif;
  font-weight: 300;
}

.coming-soon {
  opacity: 0.25;
  cursor: default;
  pointer-events: none;
}

.home-footer {
  margin-top: 5rem;
  text-align: center;
  font-family: 'Inter', sans-serif;
  font-size: 0.68rem;
  font-weight: 300;
}
.subtle-link { color: #2a2a40; text-decoration: none; }
.subtle-link:hover { color: rgba(92,156,230,0.6); }

/* ─── SVG STYLING ─── */
.viz svg text {
  font-family: 'JetBrains Mono', monospace;
}

/* ─── RESPONSIVE ─── */
@media (max-width: 600px) {
  html { font-size: 16px; }
  main { padding: 3.5rem 1.2rem 4rem; }
  .hero-title { font-size: 1rem; }
  .hero-state { font-size: 0.72rem; top: 3.8rem; padding: 0.25rem 0.8rem; }
  .hero-scene { min-height: 400px; max-height: 520px; }
  .interactive { margin: 2rem -0.3rem 2.5rem; padding: 1.3rem; }
  .controls { flex-direction: column; }
  .home { padding: 4rem 1.2rem 3rem; }
  .logo-text { font-size: 1.6rem; }
  .scene-3d { min-height: 260px; height: 35vh; max-height: 380px; }
  p { line-height: 1.9; }
}