/* ==========================================================================
   LORENTZ TRANSFORMATION & TIME DILATION SIMULATOR
   Sci-Fi Glassmorphism Physics Visualization Design System
   ========================================================================== */

:root {
  --bg-main: #090c15;
  --bg-sub: #0f1422;
  --bg-card: rgba(16, 22, 36, 0.75);
  --bg-card-hover: rgba(24, 32, 52, 0.85);
  --bg-elevated: rgba(255, 255, 255, 0.05);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-glow: rgba(56, 189, 248, 0.35);
  
  --primary: #38bdf8;
  --primary-glow: rgba(56, 189, 248, 0.4);
  --accent-cyan: #06b6d4;
  --accent-purple: #a855f7;
  --accent-emerald: #10b981;
  --accent-emerald-bright: #05df72;
  --accent-amber: #f59e0b;
  --accent-rose: #f43f5e;
  
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;
  
  --transition-fast: 0.18s ease;
  --transition-normal: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-glass: 0 8px 32px 0 rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: 'Outfit', 'Noto Sans KR', sans-serif;
  background-color: var(--bg-main);
  color: var(--text-main);
  min-height: 100vh;
  overflow-x: hidden;
  background-image: 
    radial-gradient(circle at 10% 15%, rgba(56, 189, 248, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 90% 80%, rgba(168, 85, 247, 0.07) 0%, transparent 45%);
}

.sim-standalone-app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ==========================================================================
   1. HEADER & TOP NAV
   ========================================================================== */
.sim-header {
  height: 70px;
  background: rgba(13, 18, 30, 0.92);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.back-home-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.86rem;
  font-weight: 600;
  transition: var(--transition-fast);
}

.back-home-btn:hover {
  background: rgba(56, 189, 248, 0.15);
  color: var(--primary);
  border-color: var(--primary);
  transform: translateX(-2px);
}

.title-wrap h1 {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.4px;
  background: linear-gradient(135deg, #ffffff 40%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.category-tag {
  font-size: 0.74rem;
  color: var(--primary);
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 5px;
  margin-bottom: 2px;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.engine-badge {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.76rem;
  color: var(--text-dim);
  font-family: 'JetBrains Mono', monospace;
  background: rgba(255, 255, 255, 0.04);
  padding: 5px 12px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-subtle);
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent-emerald);
  box-shadow: 0 0 8px var(--accent-emerald);
}

.icon-circle-btn {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 0.95rem;
  transition: var(--transition-fast);
}

.icon-circle-btn:hover {
  color: var(--primary);
  background: rgba(56, 189, 248, 0.15);
  border-color: var(--primary);
}

/* ==========================================================================
   2. MAIN CONTAINER & DECK
   ========================================================================== */
.sim-main-container {
  flex: 1;
  padding: 1.5rem 2rem 2.5rem;
  max-width: 1600px;
  margin: 0 auto;
  width: 100%;
}

.simulation-control-deck-banner {
  background: rgba(16, 22, 38, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-full);
  padding: 8px 18px;
  margin-bottom: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.45);
}

.deck-left-controls {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.deck-play-btn {
  background: var(--accent-emerald-bright);
  color: #000000;
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 0.88rem;
  border: none;
  padding: 7px 20px;
  border-radius: var(--radius-full);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 7px;
  transition: var(--transition-fast);
  box-shadow: 0 0 16px rgba(5, 223, 114, 0.4);
}

.deck-play-btn:hover {
  background: #22c55e;
  transform: translateY(-1px);
  box-shadow: 0 0 20px rgba(5, 223, 114, 0.6);
}

.deck-play-btn.paused {
  background: #f59e0b;
  box-shadow: 0 0 16px rgba(245, 158, 11, 0.4);
}

.deck-reset-btn {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--border-subtle);
  color: #e2e8f0;
  font-weight: 600;
  font-size: 0.84rem;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition-fast);
}

.deck-reset-btn:hover {
  background: rgba(255, 255, 255, 0.16);
  color: #fff;
  border-color: rgba(255, 255, 255, 0.25);
}

.deck-select-wrap {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.84rem;
  color: var(--text-muted);
}

.deck-label {
  display: flex;
  align-items: center;
  gap: 5px;
  color: #94a3b8;
  font-weight: 500;
  white-space: nowrap;
}

.deck-select-wrap select {
  background: #151c2e;
  color: #f1f5f9;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-md);
  padding: 5px 10px;
  font-size: 0.82rem;
  font-weight: 500;
  outline: none;
  cursor: pointer;
  transition: var(--transition-fast);
}

.deck-select-wrap select:hover,
.deck-select-wrap select:focus {
  border-color: var(--primary);
  background: #1b243b;
}

.deck-right-tools {
  display: flex;
  align-items: center;
  gap: 10px;
}

.deck-speed-badge {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.deck-speed-badge select {
  background: #151c2e;
  color: #f1f5f9;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-sm);
  padding: 3px 6px;
  font-size: 0.78rem;
  cursor: pointer;
}

.deck-icon-btn {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-subtle);
  color: var(--text-muted);
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 0.8rem;
  transition: var(--transition-fast);
}

.deck-icon-btn:hover {
  background: rgba(56, 189, 248, 0.2);
  color: var(--primary);
  border-color: var(--primary);
}

/* ==========================================================================
   3. INTRO CARD
   ========================================================================== */
.sim-intro-card {
  margin-bottom: 1.4rem;
}

.sim-meta-tags {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}

.tag-pill {
  font-size: 0.74rem;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  font-weight: 600;
  border: 1px solid transparent;
}

.tag-interactive {
  background: rgba(56, 189, 248, 0.15);
  color: #7dd3fc;
  border-color: rgba(56, 189, 248, 0.3);
}

.tag-gpu {
  background: rgba(16, 185, 129, 0.15);
  color: #6ee7b7;
  border-color: rgba(16, 185, 129, 0.3);
}

.tag-ai {
  background: rgba(168, 85, 247, 0.15);
  color: #d8b4fe;
  border-color: rgba(168, 85, 247, 0.3);
}

.sim-desc {
  color: var(--text-muted);
  font-size: 0.94rem;
  line-height: 1.55;
  max-width: 1000px;
}

/* ==========================================================================
   4. STAGE GRID (CANVAS + CONTROLS)
   ========================================================================== */
.simulation-stage-grid {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 1.5rem;
}

@media (max-width: 1100px) {
  .simulation-stage-grid {
    grid-template-columns: 1fr;
  }
}

/* 캔버스 패널 */
.canvas-panel {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-glass);
}

.canvas-toolbar {
  padding: 12px 18px;
  background: rgba(10, 13, 22, 0.7);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.canvas-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 8px;
}

.canvas-controls {
  display: flex;
  gap: 6px;
}

.view-btn {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  color: var(--text-muted);
  padding: 5px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  cursor: pointer;
  transition: var(--transition-fast);
}

.view-btn:hover, .view-btn.active {
  background: rgba(56, 189, 248, 0.2);
  color: var(--primary);
  border-color: var(--primary);
}

.canvas-container {
  position: relative;
  width: 100%;
  height: 480px;
  background: #05070f;
}

#simCanvas {
  width: 100%;
  height: 100%;
  display: block;
}

/* HUD 오버레이 */
.hud-overlay {
  position: absolute;
  top: 14px;
  left: 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  pointer-events: none;
}

.hud-item {
  background: rgba(10, 15, 25, 0.85);
  border: 1px solid rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(8px);
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-width: 220px;
}

.hud-label {
  font-size: 0.76rem;
  color: var(--text-muted);
}

.hud-val {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.88rem;
  font-weight: 700;
  color: #fff;
}

.hud-val.highlight {
  color: var(--accent-amber);
}

.hud-val.cyan {
  color: var(--primary);
}

.hud-val.green {
  color: var(--accent-emerald);
}

/* 캔버스 하단 상태 바 */
.canvas-bottom-bar {
  padding: 10px 18px;
  background: rgba(10, 13, 22, 0.7);
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.status-summary {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.text-emerald {
  color: var(--accent-emerald);
}

.text-cyan {
  color: var(--primary);
}

.fps-counter {
  font-size: 0.8rem;
  color: var(--accent-emerald);
  font-family: 'JetBrains Mono', monospace;
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ==========================================================================
   5. CONTROL PANEL & TABS
   ========================================================================== */
.control-panel {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  box-shadow: var(--shadow-glass);
}

.panel-tabs {
  display: flex;
  border-bottom: 1px solid var(--border-subtle);
  background: rgba(10, 13, 22, 0.5);
}

.panel-tab {
  flex: 1;
  background: none;
  border: none;
  padding: 12px 10px;
  color: var(--text-muted);
  font-size: 0.86rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  position: relative;
  transition: var(--transition-fast);
}

.panel-tab:hover {
  color: var(--text-main);
}

.panel-tab.active {
  color: var(--primary);
}

.panel-tab.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--primary);
}

.panel-tab-content {
  display: none;
  padding: 18px;
  overflow-y: auto;
  flex: 1;
}

.panel-tab-content.active {
  display: block;
}

/* 슬라이더 컨트롤 */
.slider-group {
  margin-bottom: 18px;
}

.slider-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.slider-header label {
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 6px;
}

.slider-val {
  font-family: 'JetBrains Mono', monospace;
  font-weight: 700;
  font-size: 0.88rem;
  color: var(--primary);
}

input[type="range"] {
  width: 100%;
  height: 5px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  outline: none;
  -webkit-appearance: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--primary);
  box-shadow: 0 0 10px var(--primary-glow);
  cursor: pointer;
  transition: transform var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.slider-ticks {
  display: flex;
  justify-content: space-between;
  font-size: 0.72rem;
  color: var(--text-dim);
  margin-top: 5px;
}

/* 추천 프리셋 */
.preset-box {
  margin-top: 22px;
  padding: 14px;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
}

.preset-title {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-muted);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.preset-chips {
  display: flex;
  flex-direction: column;
  gap: 7px;
}

.chip {
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-main);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  transition: var(--transition-fast);
}

.chip:hover {
  background: rgba(56, 189, 248, 0.15);
  border-color: var(--primary);
  color: var(--primary);
  transform: translateX(3px);
}

/* AI 튜터 챗봇 탭 */
.ai-chat-box {
  height: 320px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-right: 4px;
  margin-bottom: 12px;
}

.ai-msg {
  display: flex;
  gap: 10px;
}

.ai-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-purple), var(--primary));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  color: #fff;
  flex-shrink: 0;
}

.ai-bubble {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-subtle);
  padding: 10px 14px;
  border-radius: var(--radius-md);
  font-size: 0.84rem;
  line-height: 1.5;
  color: #e2e8f0;
}

.user-msg {
  justify-content: flex-end;
}

.user-bubble {
  background: rgba(56, 189, 248, 0.2);
  border: 1px solid rgba(56, 189, 248, 0.3);
  padding: 8px 14px;
  border-radius: var(--radius-md);
  font-size: 0.84rem;
  color: #fff;
  max-width: 82%;
}

.ai-input-wrapper {
  display: flex;
  gap: 8px;
}

.ai-input-wrapper input {
  flex: 1;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 8px 12px;
  color: #fff;
  font-size: 0.84rem;
  outline: none;
}

.ai-input-wrapper input:focus {
  border-color: var(--accent-purple);
}

.ai-input-wrapper button {
  background: var(--accent-purple);
  color: #fff;
  border: none;
  width: 38px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition-fast);
}

.ai-input-wrapper button:hover {
  filter: brightness(1.15);
}

/* 수식 탭 */
.formula-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 14px;
  margin-bottom: 14px;
}

.formula-card h4 {
  font-size: 0.88rem;
  color: var(--primary);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.latex-box {
  background: #080c16;
  border: 1px solid rgba(255, 255, 255, 0.08);
  padding: 10px;
  border-radius: var(--radius-sm);
  text-align: center;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.95rem;
  color: #38bdf8;
  margin-bottom: 8px;
}

.formula-desc {
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.45;
}

/* ==========================================================================
   6. LIGHT THEME STYLES (반전 모드)
   ========================================================================== */
body.theme-light {
  --bg-main: #f1f5f9;
  --bg-sub: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.88);
  --bg-card-hover: rgba(241, 245, 249, 0.95);
  --bg-elevated: rgba(0, 0, 0, 0.05);
  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-glow: rgba(2, 132, 199, 0.35);

  --primary: #0284c7;
  --primary-glow: rgba(2, 132, 199, 0.3);
  --accent-cyan: #0891b2;
  --accent-purple: #7c3aed;
  --accent-emerald: #059669;
  --accent-emerald-bright: #10b981;
  --accent-amber: #d97706;
  --accent-rose: #e11d48;

  --text-main: #0f172a;
  --text-muted: #475569;
  --text-dim: #64748b;

  --shadow-glass: 0 8px 30px 0 rgba(15, 23, 42, 0.07);

  background-color: var(--bg-main);
  color: var(--text-main);
  background-image: 
    radial-gradient(circle at 12% 15%, rgba(2, 132, 199, 0.08) 0%, transparent 42%),
    radial-gradient(circle at 88% 82%, rgba(124, 58, 237, 0.06) 0%, transparent 45%);
}

body.theme-light .sim-header {
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  box-shadow: 0 2px 12px rgba(15, 23, 42, 0.04);
}

body.theme-light .title-wrap h1 {
  background: linear-gradient(135deg, #0f172a 40%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

body.theme-light .back-home-btn,
body.theme-light .icon-circle-btn {
  background: rgba(0, 0, 0, 0.04);
  border-color: rgba(0, 0, 0, 0.08);
  color: #475569;
}

body.theme-light .back-home-btn:hover,
body.theme-light .icon-circle-btn:hover {
  background: rgba(2, 132, 199, 0.12);
  color: var(--primary);
}

body.theme-light .engine-badge {
  background: rgba(0, 0, 0, 0.04);
  border-color: rgba(0, 0, 0, 0.08);
}

body.theme-light .simulation-control-deck-banner {
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(0, 0, 0, 0.08);
  box-shadow: 0 6px 24px rgba(15, 23, 42, 0.06);
}

body.theme-light .deck-reset-btn {
  background: rgba(0, 0, 0, 0.04);
  border-color: rgba(0, 0, 0, 0.08);
  color: #334155;
}

body.theme-light .deck-select-wrap select,
body.theme-light .deck-speed-badge select {
  background: #f8fafc;
  color: #0f172a;
  border-color: rgba(0, 0, 0, 0.12);
}

body.theme-light .deck-icon-btn {
  background: rgba(0, 0, 0, 0.04);
  border-color: rgba(0, 0, 0, 0.08);
  color: #475569;
}

body.theme-light .canvas-panel,
body.theme-light .control-panel {
  background: #ffffff;
  border-color: rgba(0, 0, 0, 0.08);
  box-shadow: 0 8px 30px rgba(15, 23, 42, 0.06);
}

body.theme-light .canvas-toolbar,
body.theme-light .canvas-bottom-bar,
body.theme-light .panel-tabs {
  background: #f8fafc;
  border-color: rgba(0, 0, 0, 0.07);
}

body.theme-light .canvas-container {
  background: #f8fafc;
}

body.theme-light .hud-item {
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(0, 0, 0, 0.08);
  box-shadow: 0 4px 14px rgba(15, 23, 42, 0.06);
}

body.theme-light .hud-val {
  color: #0f172a;
}

body.theme-light .chip {
  background: rgba(0, 0, 0, 0.04);
  border-color: rgba(0, 0, 0, 0.08);
  color: #334155;
}

body.theme-light .formula-card {
  background: #f8fafc;
  border-color: rgba(0, 0, 0, 0.06);
}

body.theme-light .latex-box {
  background: #ffffff;
  border: 1px solid rgba(0, 0, 0, 0.08);
  color: #0284c7;
}

body.theme-light .ai-bubble {
  background: #f1f5f9;
  border-color: rgba(0, 0, 0, 0.06);
  color: #1e293b;
}

body.theme-light .ai-input-wrapper input {
  background: rgba(0, 0, 0, 0.04);
  border-color: rgba(0, 0, 0, 0.08);
  color: #0f172a;
}