/* Solar System Explorer — Premium Design System */
@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700&family=Space+Grotesk:wght@400;500;600;700&display=swap');

:root {
  --font-display: 'Outfit', system-ui, sans-serif;
  --font-mono: 'Space Grotesk', monospace;
  --space-bg: #04060a;
  --nebula-1: #0d1117;
  --nebula-2: #1a0a2e;
  --accent-gold: #fbbf24;
  --accent-blue: #3b82f6;
  --glass-bg: rgba(15, 20, 35, 0.65);
  --glass-border: rgba(255, 255, 255, 0.07);
  --glass-highlight: rgba(255, 255, 255, 0.03);
  --text-primary: #e8eaed;
  --text-secondary: rgba(232, 234, 237, 0.6);
  --text-muted: rgba(232, 234, 237, 0.35);
  --radius-lg: 16px;
  --radius-md: 10px;
  --radius-sm: 6px;
}

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

body {
  font-family: var(--font-display);
  background: var(--space-bg);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  background-image:
    radial-gradient(ellipse at 20% 50%, rgba(59,130,246,0.06) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 20%, rgba(139,92,246,0.05) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, rgba(6,182,212,0.04) 0%, transparent 50%);
}

/* === Layout === */
.app-container {
  max-width: 1340px;
  margin: 0 auto;
  padding: 20px 24px;
}

.hero {
  text-align: center;
  padding: 28px 0 20px;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 8px;
}

.text-gradient {
  background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 30%, #3b82f6 70%, #8b5cf6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  color: var(--text-secondary);
  font-size: 0.92rem;
  font-weight: 300;
}

.explorer-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 20px;
  align-items: start;
}

/* === Glass Card === */
.glass {
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

/* === Canvas Area === */
.canvas-container {
  position: relative;
}

#solar-canvas {
  display: block;
  width: 100%;
  cursor: crosshair;
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
}

/* === Controls Bar === */
.controls-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(12px);
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  flex-wrap: wrap;
}

.controls-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.ctrl-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-secondary);
  font-size: 0.78rem;
  font-family: var(--font-display);
  cursor: pointer;
  transition: all 0.25s ease;
  white-space: nowrap;
}

.ctrl-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
  border-color: rgba(255, 255, 255, 0.2);
}

.ctrl-btn.active {
  background: rgba(59, 130, 246, 0.15);
  border-color: rgba(59, 130, 246, 0.4);
  color: #93c5fd;
}

.ctrl-btn .btn-icon { font-size: 0.9rem; }

.ctrl-divider {
  width: 1px;
  height: 20px;
  background: rgba(255, 255, 255, 0.08);
  margin: 0 4px;
}

/* Slider controls */
.slider-ctrl {
  display: flex;
  align-items: center;
  gap: 6px;
}

.slider-ctrl label {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 500;
}

.slider-ctrl input[type="range"] {
  width: 80px;
  height: 4px;
  -webkit-appearance: none;
  appearance: none;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 2px;
  outline: none;
}

.slider-ctrl input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent-blue);
  cursor: pointer;
  box-shadow: 0 0 6px rgba(59, 130, 246, 0.4);
}

.slider-ctrl .speed-val {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent-blue);
  min-width: 32px;
  font-weight: 600;
}

/* === Sidebar === */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* Planet List */
.planet-list {
  padding: 16px;
}

.planet-list h3 {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.planet-btn {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 12px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  color: var(--text-primary);
  cursor: pointer;
  font-size: 0.88rem;
  font-family: var(--font-display);
  transition: all 0.2s ease;
  text-align: left;
  width: 100%;
}

.planet-btn:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.08);
  transform: translateX(4px);
}

.planet-btn.selected {
  background: rgba(251, 191, 36, 0.1);
  border-color: rgba(251, 191, 36, 0.3);
  color: #fbbf24;
  font-weight: 600;
}

.planet-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  display: inline-block;
  flex-shrink: 0;
  box-shadow: 0 0 6px currentColor;
}

/* === Planet Info Panel === */
.planet-info {
  padding: 20px;
  transition: all 0.3s ease;
}

.planet-info h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 14px;
  letter-spacing: -0.02em;
}

.size-bar-container {
  margin-bottom: 14px;
}

.size-bar-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 4px;
}

.size-bar-track {
  height: 6px;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 3px;
  overflow: hidden;
}

.size-bar-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 0 8px currentColor;
}

.info-grid {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.info-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 7px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  font-size: 0.82rem;
}

.info-label {
  color: var(--text-secondary);
  font-weight: 400;
}

.info-value {
  font-weight: 600;
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

.fact-text {
  font-size: 0.82rem;
  color: var(--text-secondary);
  font-style: italic;
  line-height: 1.5;
  padding: 10px 14px;
  background: rgba(59, 130, 246, 0.06);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent-blue);
  margin-top: 14px;
}

/* === Distance Calculator === */
.distance-calc {
  padding: 16px;
}

.distance-calc h3 {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.dist-selectors {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
}

.dist-selectors select {
  flex: 1;
  padding: 8px 10px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-display);
  font-size: 0.82rem;
  cursor: pointer;
  outline: none;
}

.dist-selectors select:focus {
  border-color: var(--accent-blue);
}

.dist-selectors select option {
  background: #1a1a2e;
}

.dist-stat {
  display: flex;
  justify-content: space-between;
  padding: 6px 0;
  font-size: 0.82rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

.dist-stat span { color: var(--text-secondary); }
.dist-stat strong {
  font-family: var(--font-mono);
  color: var(--accent-gold);
  font-size: 0.8rem;
}

.text-muted { color: var(--text-muted); }

/* === Comparison Mode === */
.comparison-panel {
  padding: 20px;
  max-height: 520px;
  overflow-y: auto;
}

.comparison-panel h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.comp-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  animation: slideIn 0.4s ease both;
}

@keyframes slideIn {
  from { opacity: 0; transform: translateX(-20px); }
  to { opacity: 1; transform: translateX(0); }
}

.comp-label {
  flex: 0 0 90px;
  font-size: 0.82rem;
  font-weight: 500;
  white-space: nowrap;
}

.comp-bar-wrap {
  flex: 1;
  height: 18px;
  background: rgba(255, 255, 255, 0.04);
  border-radius: 9px;
  overflow: hidden;
  position: relative;
}

.comp-bar {
  height: 100%;
  border-radius: 9px;
  transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.2);
}

.comp-diameter {
  flex: 0 0 80px;
  font-size: 0.75rem;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  text-align: right;
}

/* === Keyboard Shortcuts Overlay === */
.shortcuts-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.shortcuts-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  max-width: 420px;
  width: 90%;
}

.shortcuts-card h3 {
  font-size: 1.1rem;
  margin-bottom: 20px;
  text-align: center;
}

.shortcut-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  font-size: 0.85rem;
}

.shortcut-key {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 30px;
  padding: 3px 8px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 5px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 600;
}

.shortcut-desc { color: var(--text-secondary); }

.shortcuts-close {
  display: block;
  margin: 20px auto 0;
  padding: 8px 24px;
  background: rgba(59, 130, 246, 0.15);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: 20px;
  color: #93c5fd;
  font-family: var(--font-display);
  cursor: pointer;
  font-size: 0.85rem;
  transition: all 0.2s;
}

.shortcuts-close:hover {
  background: rgba(59, 130, 246, 0.25);
}

/* === Footer === */
.footer {
  text-align: center;
  padding: 24px 0;
  color: var(--text-muted);
  font-size: 0.8rem;
}

.footer a {
  color: var(--accent-blue);
  text-decoration: none;
}

.help-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 6px;
}

/* === Utilities === */
.hidden { display: none !important; }
.mb-3 { margin-bottom: 12px; }
.mt-3 { margin-top: 12px; }

/* === Fullscreen === */
:fullscreen .app-container {
  max-width: 100%;
  padding: 10px;
  height: 100vh;
}

:fullscreen .explorer-layout {
  height: calc(100vh - 80px);
}

:fullscreen .canvas-container {
  height: 100%;
}

:fullscreen #solar-canvas {
  height: calc(100% - 50px);
}

/* === Responsive === */
@media (max-width: 900px) {
  .explorer-layout {
    grid-template-columns: 1fr;
  }

  .hero h1 { font-size: 1.7rem; }

  .sidebar {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
  }

  .planet-list {
    padding: 12px;
  }

  .planet-btn {
    padding: 6px 8px;
    font-size: 0.82rem;
  }
}

@media (max-width: 600px) {
  .app-container { padding: 12px; }
  .hero h1 { font-size: 1.35rem; }
  .hero p { font-size: 0.82rem; }

  .sidebar {
    grid-template-columns: 1fr;
  }

  .controls-bar {
    gap: 6px;
    padding: 10px 12px;
  }

  .ctrl-btn {
    padding: 5px 10px;
    font-size: 0.72rem;
  }

  .slider-ctrl input[type="range"] { width: 60px; }
}