:root {
  --color-bg: #0a0a0a;
  --color-surface: #111111;
  --color-border: #2a2a2a;
  --color-primary: #00e385;
  --color-text: #ffffff;
  --color-text-muted: #888888;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 1000px;
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
}
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}
html,
body {
  overflow-y: auto;
  overflow-x: hidden;
  scrollbar-width: none;
}
html::-webkit-scrollbar,
body::-webkit-scrollbar {
  display: none;
}
body {
  font-family: "Inter", sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  font-weight: 500;
  font-size: 16px;
  line-height: 1.55;
  min-height: 100vh;
  padding: var(--space-xl);
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background: radial-gradient(circle, #202020 1px, transparent 1px);
  background-size: 20px 20px;
  opacity: 0.55;
  pointer-events: none;
  z-index: -1;
}
::selection {
  background-color: var(--color-primary);
  color: var(--color-bg);
}
button:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}
.main-layout {
  max-width: 1200px;
  margin: 0 auto;
}
/* Top Section */
.top-section {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: var(--space-xl);
  margin-bottom: var(--space-xl);
}
/* Coin Stage */
.coin-stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-xl);
  min-height: 500px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-xl);
}
.coin {
  width: 280px;
  height: 280px;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 1s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}
.heads,
.tails {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 50%;
  overflow: hidden;
}
.heads img,
.tails img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
}
.tails {
  transform: rotateY(180deg);
}
.result-display {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  padding: var(--space-md) var(--space-xl);
  border-radius: var(--radius-full);
  min-width: 180px;
  text-align: center;
  transition: border-color 0.3s ease;
}
.result-display.active {
  border-color: var(--color-primary);
}
.result-display span {
  font-size: 24px;
  color: var(--color-text);
  font-weight: 700;
  letter-spacing: 0.5px;
}
.result-display.active span {
  color: var(--color-primary);
}
/* Side Panel */
.side-panel {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}
.controls-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}
.controls-header h2,
.history-header h2 {
  font-size: 14px;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  font-weight: 700;
}
.controls-body {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}
.primary-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  background: var(--color-primary);
  border: 1px solid var(--color-primary);
  color: #000;
  padding: var(--space-md);
  font-size: 15px;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-weight: 700;
  font-family: inherit;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition:
    transform 0.1s,
    background 0.2s;
}
.primary-btn:hover {
  background: #00ff94;
}
.primary-btn:active {
  transform: scale(0.98);
}
.primary-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}
.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
}
.shortcut-hint {
  text-align: center;
  font-size: 12px;
  color: var(--color-text-muted);
}
kbd {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 2px 6px;
  font-family: inherit;
  font-size: 11px;
  color: #ccc;
}
/* Stats Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-sm);
}
.stat-card {
  background: var(--color-bg);
  padding: var(--space-md);
  border-radius: var(--radius-sm);
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  border: 1px solid var(--color-border);
  position: relative;
  overflow: hidden;
}
.stat-card::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--color-primary);
}
.stat-card.total::before {
  background: #888;
}
.stat-label {
  font-size: 10px;
  color: var(--color-text-muted);
  letter-spacing: 1px;
  text-transform: uppercase;
}
.stat-value {
  font-size: 24px;
  color: var(--color-text);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
}
/* Probabilities */
.probabilities {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-top: var(--space-xs);
}
.prob-row {
  display: grid;
  grid-template-columns: 48px 1fr 42px;
  align-items: center;
  gap: var(--space-sm);
  font-size: 13px;
  color: #aaa;
}
.prob-bar {
  height: 6px;
  background: var(--color-bg);
  border-radius: var(--radius-full);
  overflow: hidden;
  border: 1px solid var(--color-border);
}
.prob-fill {
  height: 100%;
  border-radius: var(--radius-full);
  transition: width 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  width: 50%;
}
.heads-fill {
  background: var(--color-primary);
}
.tails-fill {
  background: #888;
}
.prob-row span:last-child {
  text-align: right;
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  color: var(--color-text);
}
/* Reset Button */
.reset-btn {
  width: 100%;
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  padding: var(--space-sm) var(--space-md);
  font-size: 13px;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-weight: 600;
  font-family: inherit;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition: all 0.2s;
  margin-top: var(--space-xs);
}
.reset-btn:hover {
  background: #1a1a1a;
  border-color: #ff5555;
  color: #ff5555;
}
/* Bottom Section */
.bottom-section {
  display: grid;
  grid-template-columns: 1fr;
}
.history-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}
.history-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.history-count {
  font-size: 12px;
  color: var(--color-text-muted);
  background: var(--color-bg);
  padding: 2px 10px;
  border-radius: var(--radius-full);
}
.history-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: var(--space-sm);
  overflow-y: auto;
  padding-right: var(--space-xs);
  scrollbar-width: thin;
  scrollbar-color: #333 transparent;
}
.history-list::-webkit-scrollbar {
  width: 4px;
}
.history-list::-webkit-scrollbar-thumb {
  background: #333;
  border-radius: 2px;
}
.history-list li {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: var(--color-bg);
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  border: 1px solid transparent;
  transition: border-color 0.2s;
}
.history-list li:hover {
  border-color: #333;
}
.history-list li .flip-index {
  font-size: 10px;
  color: #555;
  min-width: 22px;
}
.history-list li .flip-result {
  color: var(--color-primary);
}
.history-empty {
  grid-column: 1 / -1;
  color: var(--color-text-muted);
  font-style: italic;
  font-weight: 400 !important;
  padding: var(--space-lg) !important;
}
/* Responsive */
@media (max-width: 960px) {
  body {
    padding: var(--space-md);
  }
  .top-section {
    grid-template-columns: 1fr;
  }
  .coin-stage {
    min-height: 380px;
  }
  .coin {
    width: 220px;
    height: 220px;
  }
  .side-panel {
    max-width: 500px;
    margin: 0 auto;
    width: 100%;
  }
}
@media (max-width: 640px) {
  body {
    padding: var(--space-md);
  }
  .page-header {
    margin-bottom: var(--space-lg);
  }
  .page-header h1 {
    font-size: 22px;
  }
  .page-header p {
    font-size: 13px;
  }
  .top-section {
    gap: var(--space-md);
    margin-bottom: var(--space-md);
  }
  .coin-stage {
    min-height: auto;
    padding: var(--space-xl) var(--space-md);
    gap: var(--space-lg);
  }
  .coin {
    width: 240px;
    height: 240px;
  }
  .result-display {
    padding: var(--space-sm) var(--space-lg);
    min-width: 140px;
  }
  .result-display span {
    font-size: 18px;
  }
  .side-panel {
    gap: var(--space-md);
  }
  .controls-card {
    padding: var(--space-md);
    gap: var(--space-md);
  }
  .stat-value {
    font-size: 20px;
  }
  .history-card {
    padding: var(--space-md);
    gap: var(--space-md);
  }
  .history-list {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    gap: var(--space-sm);
  }
}
/* Accessibility */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}