:root {
  --bg-dark: #05070e;
  --panel-bg: rgba(12, 18, 32, 0.78);
  --panel-border: rgba(100, 180, 255, 0.22);
  --accent: #38bdf8;
  --accent-glow: rgba(56, 189, 248, 0.45);
  --accent-secondary: #a855f7;
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft JhengHei", "PingFang TC", sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  user-select: none;
  -webkit-user-select: none;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: var(--bg-dark);
  color: var(--text-main);
  font-family: var(--font-sans);
}

#zoomCanvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  display: block;
  cursor: grab;
}

#zoomCanvas:active {
  cursor: grabbing;
}

/* Top Header */
.hud-header {
  position: fixed;
  top: 20px;
  left: 24px;
  right: 24px;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  pointer-events: none;
  z-index: 10;
}

.brand-box {
  pointer-events: auto;
  background: var(--panel-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  padding: 14px 20px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.45);
}

.brand-title {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  background: linear-gradient(90deg, #60a5fa, #38bdf8, #c084fc);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 4px;
}

.brand-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Scale Counter Readout */
.scale-readout {
  pointer-events: auto;
  background: var(--panel-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  padding: 12px 22px;
  text-align: right;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.45);
  min-width: 230px;
}

.scale-power {
  font-family: var(--font-mono);
  font-size: 1.65rem;
  font-weight: 700;
  color: var(--accent);
  text-shadow: 0 0 14px var(--accent-glow);
}

.scale-power sup {
  font-size: 1rem;
  color: #e0f2fe;
}

.scale-unit-text {
  font-size: 0.88rem;
  color: #cbd5e1;
  margin-top: 2px;
  font-family: var(--font-mono);
}

/* Left Navigation Milestones */
.milestones-nav {
  position: fixed;
  left: 24px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--panel-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--panel-border);
  border-radius: 16px;
  padding: 10px 8px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  z-index: 10;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.45);
  max-height: 72vh;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(56, 189, 248, 0.35) transparent;
}

.milestones-nav::-webkit-scrollbar {
  width: 5px;
}

.milestones-nav::-webkit-scrollbar-thumb {
  background: rgba(56, 189, 248, 0.35);
  border-radius: 999px;
}

.milestone-btn {
  display: flex;
  align-items: center;
  gap: 9px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-muted);
  padding: 6px 10px;
  border-radius: 9px;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.82rem;
  text-align: left;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.milestone-btn:hover {
  color: var(--text-main);
  background: rgba(56, 189, 248, 0.1);
  border-color: rgba(56, 189, 248, 0.25);
}

.milestone-btn.active {
  color: #fff;
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.28), rgba(168, 85, 247, 0.24));
  border-color: var(--accent);
  box-shadow: 0 0 14px rgba(56, 189, 248, 0.25);
  font-weight: 600;
}

.milestone-icon {
  font-size: 1.15rem;
  width: 24px;
  text-align: center;
}

.milestone-meta {
  display: flex;
  flex-direction: column;
}

.milestone-name {
  line-height: 1.2;
}

.milestone-exp {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: #64748b;
}

.milestone-btn.active .milestone-exp {
  color: #bae6fd;
}

/* Right Info Card */
.info-panel {
  position: fixed;
  right: 24px;
  top: 50%;
  transform: translateY(-50%);
  width: 320px;
  background: var(--panel-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--panel-border);
  border-radius: 16px;
  padding: 20px;
  z-index: 10;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.45);
  transition: border-color 0.3s ease;
}

.info-badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background: rgba(56, 189, 248, 0.18);
  color: var(--accent);
  border: 1px solid rgba(56, 189, 248, 0.35);
  margin-bottom: 10px;
}

.info-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 2px;
}

.info-en {
  font-size: 0.82rem;
  color: var(--accent);
  margin-bottom: 12px;
  font-weight: 500;
}

.info-size-row {
  display: flex;
  justify-content: space-between;
  background: rgba(255, 255, 255, 0.04);
  border-radius: 8px;
  padding: 8px 12px;
  margin-bottom: 12px;
  font-size: 0.82rem;
  border: 1px solid rgba(255, 255, 255, 0.07);
}

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

.info-size-val {
  font-family: var(--font-mono);
  color: #e2e8f0;
  font-weight: 600;
}

.info-desc {
  font-size: 0.88rem;
  line-height: 1.65;
  color: #cbd5e1;
  margin-bottom: 14px;
}

.info-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.info-tag {
  font-size: 0.74rem;
  padding: 4px 9px;
  border-radius: 6px;
  background: rgba(148, 163, 184, 0.12);
  color: #e2e8f0;
  border: 1px solid rgba(148, 163, 184, 0.2);
}

/* Bottom Controls & Slider */
.bottom-bar {
  position: fixed;
  bottom: 22px;
  left: 50%;
  transform: translateX(-50%);
  width: min(760px, 92vw);
  background: var(--panel-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--panel-border);
  border-radius: 16px;
  padding: 14px 20px;
  z-index: 10;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.controls-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

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

.ctrl-btn {
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: var(--text-main);
  padding: 7px 14px;
  border-radius: 9px;
  font-size: 0.84rem;
  font-family: var(--font-sans);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all 0.2s ease;
}

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

.ctrl-btn.primary {
  background: linear-gradient(135deg, #0284c7, #7c3aed);
  border-color: rgba(125, 211, 252, 0.5);
  font-weight: 600;
}

.ctrl-btn.primary:hover {
  filter: brightness(1.15);
}

.ctrl-btn.active {
  background: linear-gradient(135deg, #dc2626, #ea580c);
  border-color: #fca5a5;
}

/* Slider styling */
.slider-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.slider-EndLabel {
  font-size: 0.76rem;
  color: var(--text-muted);
  white-space: nowrap;
  font-family: var(--font-mono);
}

.scale-slider {
  flex: 1;
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  border-radius: 999px;
  background: linear-gradient(90deg, #3b82f6 0%, #10b981 35%, #f59e0b 70%, #ec4899 100%);
  outline: none;
  cursor: pointer;
}

.scale-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: #fff;
  border: 3px solid var(--accent);
  box-shadow: 0 0 12px var(--accent-glow);
  cursor: grab;
  transition: transform 0.15s ease;
}

.scale-slider::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

/* Dynamic Scale Bar Indicator */
.scale-bar-widget {
  display: flex;
  align-items: center;
  gap: 10px;
}

.scale-bar-graphic {
  height: 8px;
  border-left: 2px solid var(--accent);
  border-right: 2px solid var(--accent);
  border-bottom: 2px solid var(--accent);
  width: 90px;
  transition: width 0.1s linear;
  position: relative;
}

.scale-bar-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: #bae6fd;
  min-width: 75px;
}

.hint-text {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Responsive adjustments */
@media (max-width: 960px) {
  .milestones-nav {
    top: auto;
    bottom: 138px;
    left: 50%;
    transform: translateX(-50%);
    flex-direction: row;
    max-width: 92vw;
    overflow-x: auto;
    padding: 8px;
  }
  .milestone-meta {
    display: none;
  }
  .info-panel {
    top: 95px;
    right: 16px;
    transform: none;
    width: 270px;
    padding: 14px;
  }
}