/* ================================================================
   UNIVERSE EXPLORER — Sci-fi HUD Design System
   ================================================================ */

:root {
  --font-display: 'Orbitron', 'Courier New', monospace;
  --font-body: 'Inter', 'Helvetica Neue', sans-serif;
  
  --color-bg: #050508;
  --color-surface: rgba(8, 16, 32, 0.85);
  --color-surface-solid: #0a1428;
  --color-border: rgba(60, 140, 220, 0.2);
  --color-border-bright: rgba(80, 170, 255, 0.35);
  --color-text: #c8d8e8;
  --color-text-muted: #6888a8;
  --color-text-faint: #3a5068;
  --color-accent: #4ac0ff;
  --color-accent-dim: rgba(74, 192, 255, 0.15);
  --color-accent-glow: rgba(74, 192, 255, 0.4);
  --color-warn: #ff9a40;
  --color-danger: #ff4466;
  --color-success: #40ff90;

  --panel-blur: 16px;
  --panel-radius: 6px;
  --transition-ui: 200ms cubic-bezier(0.16, 1, 0.3, 1);

  --text-xs: 10px;
  --text-sm: 12px;
  --text-base: 14px;
  --text-lg: 16px;
  --text-xl: 20px;
  --text-2xl: 28px;

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-6: 24px;
  --space-8: 32px;
}

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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: var(--text-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  user-select: none;
}

canvas { display: block; }

/* ================================================================
   LOADING SCREEN
   ================================================================ */
#loading-screen {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #050508;
  transition: opacity 0.8s ease, visibility 0.8s ease;
}

#loading-screen.fade-out {
  opacity: 0;
  visibility: hidden;
}

.loading-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-6);
}

.loading-logo {
  animation: pulse-glow 2s ease-in-out infinite;
}

@keyframes pulse-glow {
  0%, 100% { filter: drop-shadow(0 0 8px rgba(100, 200, 255, 0.3)); }
  50% { filter: drop-shadow(0 0 20px rgba(100, 200, 255, 0.6)); }
}

.loading-title {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  letter-spacing: 0.3em;
  color: var(--color-accent);
  text-shadow: 0 0 20px rgba(74, 192, 255, 0.4);
}

.loading-bar-container {
  width: 240px;
  height: 2px;
  background: rgba(74, 192, 255, 0.1);
  border-radius: 1px;
  overflow: hidden;
}

.loading-bar {
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--color-accent), #80dfff);
  border-radius: 1px;
  transition: width 0.3s ease;
  box-shadow: 0 0 8px var(--color-accent-glow);
}

.loading-text {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* ================================================================
   CANVAS
   ================================================================ */
#canvas-container {
  position: fixed;
  inset: 0;
  z-index: 1;
}

/* ================================================================
   HUD OVERLAY
   ================================================================ */
.hud {
  position: fixed;
  inset: 0;
  z-index: 10;
  pointer-events: none;
  transition: opacity var(--transition-ui);
}

.hud.hidden {
  opacity: 0;
  pointer-events: none;
}

.hud > * { pointer-events: auto; }

/* ================================================================
   TOP BAR
   ================================================================ */
.hud-top-bar {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-4);
  background: linear-gradient(180deg, rgba(5, 5, 8, 0.7) 0%, transparent 100%);
  border-bottom: 1px solid var(--color-border);
}

.hud-top-left {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.hud-brand {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.2em;
  color: var(--color-accent);
}

.hud-top-center {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}

.hud-scale-label {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.15em;
  color: var(--color-text);
  text-shadow: 0 0 10px rgba(74, 192, 255, 0.3);
}

.hud-top-right {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.hud-fps {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  color: var(--color-success);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.05em;
}

.hud-btn {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: var(--panel-radius);
  color: var(--color-text-muted);
  background: var(--color-surface);
  backdrop-filter: blur(var(--panel-blur));
  cursor: pointer;
  transition: all var(--transition-ui);
}

.hud-btn:hover {
  color: var(--color-accent);
  border-color: var(--color-border-bright);
  background: var(--color-accent-dim);
}

/* ================================================================
   PANELS
   ================================================================ */
.hud-panel {
  position: absolute;
  top: 64px;
  width: 260px;
  background: var(--color-surface);
  backdrop-filter: blur(var(--panel-blur));
  border: 1px solid var(--color-border);
  border-radius: var(--panel-radius);
  overflow: hidden;
  transition: transform var(--transition-ui), opacity var(--transition-ui);
}

.hud-panel-left { left: var(--space-4); }
.hud-panel-right { right: var(--space-4); }

.panel-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--color-accent);
}

.panel-body {
  padding: var(--space-3);
}

/* Info Panel */
.info-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 3px 0;
}

.info-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.info-value {
  font-size: var(--text-sm);
  color: var(--color-text);
  font-variant-numeric: tabular-nums;
  text-align: right;
}

.info-divider {
  height: 1px;
  background: var(--color-border);
  margin: var(--space-2) 0;
}

.info-description {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* Navigation Panel */
.nav-section {
  margin-bottom: var(--space-3);
}

.nav-section:last-child { margin-bottom: 0; }

.nav-section-title {
  display: block;
  font-family: var(--font-display);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--color-text-faint);
  margin-bottom: var(--space-2);
}

.nav-buttons {
  display: flex;
  flex-direction: column;
  gap: 2px;
  max-height: 240px;
  overflow-y: auto;
}

.nav-buttons::-webkit-scrollbar { width: 3px; }
.nav-buttons::-webkit-scrollbar-track { background: transparent; }
.nav-buttons::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 2px; }

.nav-btn {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: 5px var(--space-2);
  border: none;
  border-radius: 3px;
  background: transparent;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-family: var(--font-body);
  cursor: pointer;
  transition: all var(--transition-ui);
  text-align: left;
}

.nav-btn:hover {
  background: var(--color-accent-dim);
  color: var(--color-text);
}

.nav-btn.active {
  background: var(--color-accent-dim);
  color: var(--color-accent);
}

.nav-btn-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* Scale Buttons */
.scale-buttons {
  display: flex;
  gap: 2px;
}

.scale-btn {
  flex: 1;
  padding: 5px 2px;
  border: 1px solid var(--color-border);
  border-radius: 3px;
  background: transparent;
  color: var(--color-text-muted);
  font-family: var(--font-display);
  font-size: 9px;
  font-weight: 500;
  letter-spacing: 0.05em;
  cursor: pointer;
  transition: all var(--transition-ui);
}

.scale-btn:hover {
  border-color: var(--color-border-bright);
  color: var(--color-text);
}

.scale-btn.active {
  border-color: var(--color-accent);
  background: var(--color-accent-dim);
  color: var(--color-accent);
}

/* ================================================================
   BOTTOM BAR
   ================================================================ */
.hud-bottom-bar {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-4);
  background: linear-gradient(0deg, rgba(5, 5, 8, 0.7) 0%, transparent 100%);
  border-top: 1px solid var(--color-border);
}

/* Scale Ruler */
.scale-indicator {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.scale-ruler {
  position: relative;
  width: 80px;
  height: 8px;
}

.scale-ruler-line {
  position: absolute;
  top: 50%;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-accent);
  opacity: 0.6;
}

.scale-ruler-tick {
  position: absolute;
  top: 0;
  width: 1px;
  height: 100%;
  background: var(--color-accent);
  opacity: 0.6;
}

.scale-ruler-tick.left { left: 0; }
.scale-ruler-tick.right { right: 0; }

.scale-value {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.05em;
}

/* Zoom Indicator */
.zoom-indicator {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.zoom-label {
  font-family: var(--font-display);
  font-size: 9px;
  color: var(--color-text-faint);
  letter-spacing: 0.1em;
}

.zoom-bar {
  position: relative;
  width: 200px;
  height: 4px;
  background: rgba(74, 192, 255, 0.08);
  border-radius: 2px;
  overflow: visible;
}

.zoom-fill {
  height: 100%;
  width: 20%;
  background: linear-gradient(90deg, var(--color-accent), rgba(74, 192, 255, 0.4));
  border-radius: 2px;
  transition: width 0.5s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow: 0 0 6px var(--color-accent-glow);
}

.zoom-markers {
  position: absolute;
  top: 8px;
  left: 0;
  right: 0;
  display: flex;
  justify-content: space-between;
}

.zoom-markers span {
  font-family: var(--font-display);
  font-size: 8px;
  color: var(--color-text-faint);
  letter-spacing: 0.05em;
}

/* Coordinates */
.coord-display {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.coord-label {
  font-family: var(--font-display);
  font-size: 9px;
  color: var(--color-text-faint);
  letter-spacing: 0.1em;
}

.coord-value {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
}

/* ================================================================
   CROSSHAIR
   ================================================================ */
.crosshair {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  pointer-events: none;
}

.crosshair-h, .crosshair-v {
  position: absolute;
  background: rgba(100, 200, 255, 0.15);
}

.crosshair-h {
  width: 24px;
  height: 1px;
  top: 0;
  left: -12px;
}

.crosshair-v {
  width: 1px;
  height: 24px;
  top: -12px;
  left: 0;
}

.crosshair-circle {
  position: absolute;
  width: 8px;
  height: 8px;
  border: 1px solid rgba(100, 200, 255, 0.2);
  border-radius: 50%;
  top: -4px;
  left: -4px;
}

/* ================================================================
   MODAL
   ================================================================ */
.modal {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  transition: opacity var(--transition-ui), visibility var(--transition-ui);
}

.modal.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.modal-content {
  width: 400px;
  background: var(--color-surface-solid);
  border: 1px solid var(--color-border);
  border-radius: var(--panel-radius);
  overflow: hidden;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
}

.modal-header h2 {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--color-accent);
}

.modal-close {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: none;
  color: var(--color-text-muted);
  font-size: 18px;
  cursor: pointer;
  border-radius: var(--panel-radius);
  transition: all var(--transition-ui);
}

.modal-close:hover {
  color: var(--color-text);
  background: var(--color-accent-dim);
}

.modal-body {
  padding: var(--space-4);
}

.control-group {
  margin-bottom: var(--space-4);
}

.control-group:last-child { margin-bottom: 0; }

.control-group h3 {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}

.control-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 3px 0;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

kbd {
  display: inline-block;
  min-width: 56px;
  padding: 2px 8px;
  border: 1px solid var(--color-border);
  border-radius: 3px;
  background: rgba(74, 192, 255, 0.05);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  color: var(--color-accent);
  text-align: center;
}

/* ================================================================
   OBJECT LABELS (3D overlay)
   ================================================================ */
.object-label {
  position: absolute;
  pointer-events: auto;
  cursor: pointer;
  white-space: nowrap;
  font-family: var(--font-display);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: rgba(180, 210, 240, 0.7);
  text-shadow: 0 0 4px rgba(0,0,0,0.8), 0 0 8px rgba(74, 192, 255, 0.2);
  transition: color 0.15s, text-shadow 0.15s;
  transform: translate(-50%, 0);
  padding: 2px 6px;
}

.object-label:hover {
  color: var(--color-accent);
  text-shadow: 0 0 4px rgba(0,0,0,0.8), 0 0 12px rgba(74, 192, 255, 0.5);
}

.object-label .label-dot {
  display: inline-block;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  margin-right: 4px;
  vertical-align: middle;
}

/* ================================================================
   SELECTION RING
   ================================================================ */
.selection-indicator {
  position: absolute;
  pointer-events: none;
  border: 1px solid rgba(74, 192, 255, 0.5);
  border-radius: 50%;
  box-shadow: 0 0 8px rgba(74, 192, 255, 0.2), inset 0 0 8px rgba(74, 192, 255, 0.1);
  transition: all 0.3s ease;
}

/* ================================================================
   FOOTER ATTRIBUTION
   ================================================================ */
.attribution {
  position: fixed;
  bottom: 50px;
  right: var(--space-4);
  z-index: 5;
}

.attribution a {
  font-size: 9px;
  color: var(--color-text-faint);
  text-decoration: none;
  letter-spacing: 0.05em;
  transition: color var(--transition-ui);
}

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

/* ================================================================
   SCROLLBAR
   ================================================================ */
::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 2px; }

/* ================================================================
   LABEL CONTAINER 
   ================================================================ */
#label-container {
  position: fixed;
  inset: 0;
  z-index: 9;
  pointer-events: none;
  overflow: hidden;
}

#label-container .object-label {
  pointer-events: auto;
}

/* Tooltip on hover for celestial objects */
.object-tooltip {
  position: absolute;
  background: var(--color-surface);
  backdrop-filter: blur(var(--panel-blur));
  border: 1px solid var(--color-border-bright);
  border-radius: var(--panel-radius);
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-xs);
  color: var(--color-text);
  pointer-events: none;
  white-space: nowrap;
  z-index: 20;
  opacity: 0;
  transition: opacity 0.15s;
}

.object-tooltip.visible { opacity: 1; }

/* ================================================================
   SATELLITE PANEL
   ================================================================ */
#satellite-panel {
  backdrop-filter: blur(var(--panel-blur));
  -webkit-backdrop-filter: blur(var(--panel-blur));
}

#satellite-panel::-webkit-scrollbar { width: 3px; }
#satellite-panel::-webkit-scrollbar-track { background: transparent; }
#satellite-panel::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 2px; }

.sat-result-item:hover {
  background: rgba(68, 170, 255, 0.15) !important;
  color: #fff !important;
}

#sat-search-input:focus {
  border-color: var(--color-accent) !important;
  box-shadow: 0 0 6px rgba(74, 192, 255, 0.2);
}

/* ================================================================
   STAR SEARCH
   ================================================================ */
#star-search-container {
  margin-bottom: var(--space-3);
}

#star-search-input {
  width: 100%;
  box-sizing: border-box;
  background: rgba(0, 20, 40, 0.7);
  border: 1px solid var(--color-border);
  border-radius: 3px;
  padding: 5px 8px;
  color: var(--color-accent);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  outline: none;
  transition: border-color var(--transition-ui);
}

#star-search-input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 6px rgba(74, 192, 255, 0.2);
}

#star-search-input::placeholder {
  color: var(--color-text-faint);
}

#star-search-results {
  margin-top: 4px;
}

.star-search-item {
  padding: 4px 6px;
  cursor: pointer;
  border-radius: 3px;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: background 0.1s;
}

.star-search-item:hover {
  background: var(--color-accent-dim);
  color: var(--color-text);
}

/* ================================================================
   RESPONSIVE — Mobile adjustments
   ================================================================ */
@media (max-width: 768px) {
  .hud-panel {
    width: 200px;
  }
  
  .hud-panel-left {
    left: var(--space-2);
  }
  
  .hud-panel-right {
    right: var(--space-2);
  }
  
  #satellite-panel {
    width: 200px !important;
    left: 8px !important;
    bottom: 60px !important;
    font-size: 10px !important;
  }
  
  .zoom-bar {
    width: 120px;
  }
  
  .hud-brand {
    display: none;
  }
}

@media (max-width: 480px) {
  .hud-panel {
    width: 160px;
    font-size: 10px;
  }
  
  .hud-bottom-bar {
    height: 36px;
  }
  
  .zoom-bar {
    width: 80px;
  }
  
  #satellite-panel {
    width: 160px !important;
    max-height: 250px !important;
  }
}