@import url('https://fonts.googleapis.com/css2?family=Fira+Code:wght@400;500;600&family=Fira+Sans:wght@300;400;500;600;700&display=swap');

:root {
  --bg-base: #0a0e13;
  --bg-panel: #11161e;
  --bg-elevated: #161d26;
  --bg-hover: #1c242f;
  --border: #232b38;
  --border-strong: #2f394a;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-dim: #64748b;
  --accent: #f97316;
  --accent-glow: rgba(249, 115, 22, 0.35);
  --accent-soft: rgba(249, 115, 22, 0.12);
  --success: #10b981;
  --warning: #fbbf24;
  --error: #ef4444;
  --info: #38bdf8;

  --font-display: 'Fira Sans', -apple-system, "PingFang SC", "Hiragino Sans GB", sans-serif;
  --font-mono: 'Fira Code', ui-monospace, "JetBrains Mono", Menlo, monospace;
  --font-cn: -apple-system, "PingFang SC", "Hiragino Sans GB", sans-serif;

  --radius-sm: 3px;
  --radius: 6px;
  --radius-lg: 10px;

  --shadow-elevated: 0 4px 24px rgba(0,0,0,0.4);
  --glow-accent: 0 0 20px var(--accent-glow);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html, body {
  font-family: var(--font-display);
  background: var(--bg-base);
  color: var(--text-primary);
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
  font-feature-settings: "ss01", "cv01";
  -webkit-font-smoothing: antialiased;
}

body {
  display: grid;
  grid-template-rows: auto 1fr auto;
  background-image:
    radial-gradient(circle at 20% 10%, rgba(249, 115, 22, 0.04), transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(56, 189, 248, 0.03), transparent 50%),
    linear-gradient(rgba(255,255,255,0.012) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.012) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 40px 40px, 40px 40px;
}

/* ===== HEADER ===== */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 28px;
  background: linear-gradient(180deg, var(--bg-panel) 0%, rgba(17, 22, 30, 0.85) 100%);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
  position: relative;
}

header::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 28px;
  width: 80px;
  height: 1px;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent-glow);
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-mark {
  width: 32px;
  height: 32px;
  border: 1.5px solid var(--accent);
  border-radius: var(--radius-sm);
  display: grid;
  place-items: center;
  position: relative;
  background: var(--accent-soft);
}

.brand-mark::before,
.brand-mark::after {
  content: '';
  position: absolute;
  background: var(--accent);
}

.brand-mark::before {
  width: 12px;
  height: 2px;
  border-radius: 1px;
}

.brand-mark::after {
  width: 2px;
  height: 12px;
  border-radius: 1px;
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand-name {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.3px;
  color: var(--text-primary);
}

.brand-meta {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-dim);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.mode-buttons {
  display: flex;
  gap: 0;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  overflow: hidden;
  padding: 3px;
  background: var(--bg-elevated);
}

.mode-btn {
  padding: 7px 18px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.2px;
  transition: all 200ms ease;
  border-radius: var(--radius-sm);
  position: relative;
  min-height: 32px;
}

.mode-btn:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.mode-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.mode-btn.active {
  background: var(--accent);
  color: #0a0e13;
  font-weight: 600;
  box-shadow: 0 0 12px var(--accent-glow);
}

.system-status {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-secondary);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--success);
  box-shadow: 0 0 8px var(--success);
  animation: pulse 2s ease-in-out infinite;
}

.status-dot.warning { background: var(--warning); box-shadow: 0 0 8px var(--warning); }
.status-dot.error { background: var(--error); box-shadow: 0 0 8px var(--error); }

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* ===== MAIN ===== */
main {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 18px;
  padding: 18px 28px;
  overflow: hidden;
  min-height: 0;
}

/* ===== CAMERA ===== */
.camera-section {
  position: relative;
  background: #000;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border-strong);
}

/* video 必须在视口内才会渲染像素，但视觉隐藏 */
.hidden-video {
  position: absolute;
  width: 2px;
  height: 2px;
  opacity: 0.01;
  top: 0;
  left: 0;
  pointer-events: none;
  z-index: -1;
  object-fit: cover;
}

/* 启动覆盖层 */
.start-overlay,
.error-overlay {
  position: absolute;
  inset: 0;
  z-index: 10;
  background: linear-gradient(135deg, rgba(10,14,19,0.96), rgba(22,29,38,0.96));
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  animation: fadeIn 300ms ease;
}

.error-overlay { background: linear-gradient(135deg, rgba(48, 14, 14, 0.95), rgba(22,29,38,0.95)); }

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

.start-overlay-inner,
.error-inner {
  text-align: center;
  max-width: 360px;
  padding: 28px 24px;
  background: rgba(10, 14, 19, 0.6);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  position: relative;
}

.start-overlay-inner::before,
.error-inner::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 24px;
  width: 60px;
  height: 1px;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent-glow);
}

.start-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 16px;
  border: 1.5px solid var(--accent);
  border-radius: var(--radius);
  display: grid;
  place-items: center;
  color: var(--accent);
  background: var(--accent-soft);
}

.start-icon svg { width: 28px; height: 28px; }

.start-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
  letter-spacing: 0.3px;
}

.start-desc {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 20px;
}

.start-btn {
  background: var(--accent);
  color: #0a0e13;
  border: none;
  padding: 12px 32px;
  border-radius: var(--radius);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  letter-spacing: 1.5px;
  transition: all 200ms ease;
  min-height: 44px;
  box-shadow: 0 0 16px var(--accent-glow);
  margin-bottom: 14px;
}

.start-btn:hover, .start-btn:focus-visible {
  background: #fb923c;
  box-shadow: 0 0 24px var(--accent-glow), 0 4px 16px rgba(0,0,0,0.3);
  transform: translateY(-1px);
}

.start-btn:active { transform: translateY(0); }

.start-hint {
  font-size: 11px;
  color: var(--text-dim);
  font-family: var(--font-mono);
  letter-spacing: 0.5px;
}

.error-inner h3 {
  color: var(--error);
  font-size: 16px;
  font-weight: 600;
  margin: 12px 0 8px;
}

.error-inner p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 20px;
  word-break: break-word;
}

.error-inner svg { color: var(--error); }

#canvas {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  transition: filter 300ms ease;
}

#canvas.canvas-error { filter: brightness(0.7) saturate(1.4); }
#canvas.canvas-success { filter: brightness(1.05); }

/* HUD 角框 */
.hud-corners::before,
.hud-corners::after,
.hud-corners > .hud-corner {
  content: '';
  position: absolute;
  width: 24px;
  height: 24px;
  border-color: var(--accent);
  border-style: solid;
  pointer-events: none;
  filter: drop-shadow(0 0 4px var(--accent-glow));
}

.hud-corners {
  position: absolute;
  inset: 12px;
  pointer-events: none;
  z-index: 2;
}

.hud-corners::before {
  top: 0; left: 0;
  border-width: 2px 0 0 2px;
}

.hud-corners::after {
  top: 0; right: 0;
  border-width: 2px 2px 0 0;
}

.hud-corners > .corner-bl {
  bottom: 0; left: 0; top: auto;
  border-width: 0 0 2px 2px;
}

.hud-corners > .corner-br {
  bottom: 0; right: 0; top: auto;
  border-width: 0 2px 2px 0;
}

/* 状态/错误时角框变色 */
#canvas.canvas-error ~ .hud-corners::before,
#canvas.canvas-error ~ .hud-corners::after,
#canvas.canvas-error ~ .hud-corners > .hud-corner {
  border-color: var(--error);
  filter: drop-shadow(0 0 4px var(--error));
}

#canvas.canvas-success ~ .hud-corners::before,
#canvas.canvas-success ~ .hud-corners::after,
#canvas.canvas-success ~ .hud-corners > .hud-corner {
  border-color: var(--success);
  filter: drop-shadow(0 0 6px var(--success));
}

/* HUD 顶部信息 */
.hud-top {
  position: absolute;
  top: 14px;
  left: 24px;
  right: 24px;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  z-index: 3;
  pointer-events: none;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-secondary);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.hud-rec {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(10, 14, 19, 0.7);
  backdrop-filter: blur(6px);
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.rec-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--error);
  animation: pulse 1.2s ease-in-out infinite;
}

.hud-camera-switch {
  pointer-events: auto;
  background: rgba(10, 14, 19, 0.7);
  backdrop-filter: blur(6px);
  border: 1px solid var(--border);
  color: var(--text-primary);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all 200ms ease;
  min-height: 28px;
}

.hud-camera-switch:hover {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}

.hud-camera-switch:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.hud-camera-switch svg {
  width: 12px;
  height: 12px;
}

/* HUD 底部信息 */
.hud-bottom {
  position: absolute;
  bottom: 14px;
  left: 24px;
  right: 24px;
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  z-index: 3;
  pointer-events: none;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-secondary);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.hud-stat {
  display: flex;
  flex-direction: column;
  gap: 2px;
  background: rgba(10, 14, 19, 0.7);
  backdrop-filter: blur(6px);
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  min-width: 90px;
}

.hud-stat-label {
  color: var(--text-dim);
  font-size: 9px;
}

.hud-stat-value {
  color: var(--text-primary);
  font-size: 13px;
  font-weight: 500;
}

/* 扫描线动画 */
.scan-line {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: linear-gradient(180deg, transparent, var(--accent-soft), transparent);
  pointer-events: none;
  z-index: 1;
  animation: scan 6s linear infinite;
  opacity: 0.6;
}

@keyframes scan {
  0% { transform: translateY(-60px); }
  100% { transform: translateY(calc(100% + 60px)); }
}

/* ===== 状态面板 ===== */
.status-section {
  display: flex;
  flex-direction: column;
  gap: 12px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) transparent;
}

.status-section::-webkit-scrollbar { width: 6px; }
.status-section::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 3px;
}

.status-card {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  position: relative;
}

.status-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 16px;
  width: 32px;
  height: 1px;
  background: var(--accent);
  opacity: 0.6;
}

.status-card h3 {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--accent);
  margin-bottom: 12px;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 6px;
}

.status-card h3::before {
  content: '//';
  color: var(--text-dim);
  margin-right: 2px;
}

.status-card p {
  font-size: 13px;
  line-height: 1.55;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.status-card p:last-child { margin-bottom: 0; }

#hand-count {
  font-weight: 500;
  font-size: 14px;
}

#gesture-name, #hand-zone {
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 12px;
}

/* 步骤列表 */
#step-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

#step-list li {
  padding: 7px 10px;
  font-size: 13px;
  border-left: 2px solid transparent;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 200ms ease;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-feature-settings: "tnum";
}

.step-done {
  color: var(--success) !important;
  border-left-color: var(--success) !important;
  background: rgba(16, 185, 129, 0.05);
}

.step-current {
  color: var(--accent) !important;
  border-left-color: var(--accent) !important;
  background: var(--accent-soft);
  font-weight: 500;
  box-shadow: inset 0 0 0 1px rgba(249, 115, 22, 0.2);
}

.step-pending {
  color: var(--text-dim);
  border-left-color: var(--border);
}

/* 触发条件 */
#trigger-list { list-style: none; display: flex; flex-direction: column; gap: 4px; }

#trigger-list li {
  padding: 6px 10px;
  font-size: 12px;
  font-family: var(--font-mono);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  transition: all 200ms ease;
}

.trigger-ok {
  color: var(--success);
  border-color: rgba(16, 185, 129, 0.3) !important;
  background: rgba(16, 185, 129, 0.05) !important;
}

.trigger-fail {
  color: var(--warning);
  border-color: rgba(251, 191, 36, 0.25) !important;
  background: rgba(251, 191, 36, 0.04) !important;
}

/* 反馈 */
#feedback-text {
  font-size: 13px;
  line-height: 1.5;
  font-weight: 500;
  letter-spacing: 0.2px;
}

.feedback-normal { color: var(--text-secondary); font-weight: 400 !important; }
.feedback-error { color: var(--error); }
.feedback-success { color: var(--success); }
.feedback-guide, .feedback-warning { color: var(--accent); }

/* ===== FOOTER ===== */
footer {
  background: var(--bg-panel);
  border-top: 1px solid var(--border);
  padding: 10px 28px 12px;
  max-height: 130px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) transparent;
}

footer::-webkit-scrollbar { height: 4px; width: 4px; }
footer::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 2px; }

footer h3 {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-dim);
  margin-bottom: 6px;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 6px;
}

footer h3::before {
  content: '~';
  color: var(--accent);
  font-weight: 700;
}

#log-list {
  list-style: none;
  display: flex;
  flex-direction: column-reverse;
}

#log-list li {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-dim);
  padding: 1px 0;
  letter-spacing: 0.2px;
  animation: logIn 300ms ease-out;
}

#log-list li:first-child {
  color: var(--text-secondary);
}

@keyframes logIn {
  from { opacity: 0; transform: translateX(-4px); }
  to { opacity: 1; transform: translateX(0); }
}

/* ===== 移动端适配 ===== */
@media (max-width: 900px) {
  html, body {
    height: auto;
    min-height: 100vh;
    min-height: 100dvh;
    overflow: visible;
  }

  body {
    grid-template-rows: auto auto auto;
  }

  header {
    padding: 10px 14px;
    flex-wrap: wrap;
    gap: 10px;
    position: sticky;
    top: 0;
    z-index: 20;
  }

  .brand-name { font-size: 14px; }
  .brand-meta { font-size: 9px; }
  .system-status { font-size: 10px; }
  .system-status .system-status-text { display: none; }

  .mode-buttons { order: 3; flex: 1 1 100%; }
  .mode-btn { flex: 1; padding: 9px 14px; min-height: 40px; font-size: 13px; }

  main {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto;
    padding: 10px;
    gap: 10px;
    overflow: visible;
  }

  .camera-section {
    width: 100%;
    aspect-ratio: 4 / 3;
    max-height: 50vh;
  }

  .hud-corners { inset: 8px; }
  .hud-corners::before,
  .hud-corners::after,
  .hud-corners > .hud-corner {
    width: 18px; height: 18px;
  }

  .hud-top, .hud-bottom {
    left: 12px;
    right: 12px;
  }
  .hud-top { top: 10px; }
  .hud-bottom { bottom: 10px; }

  .hud-rec, .hud-camera-switch, .hud-stat {
    padding: 4px 8px;
    font-size: 9px;
  }
  .hud-camera-switch span:not(.rec-dot) { display: none; }
  .hud-camera-switch { padding: 6px 8px; min-width: 32px; min-height: 32px; }
  .hud-stat-value { font-size: 11px; }
  .hud-stat { min-width: auto; }

  .status-section {
    gap: 8px;
    overflow: visible;
    max-height: none;
  }
  .status-card { padding: 11px 13px; }
  .status-card h3 { font-size: 9px; margin-bottom: 8px; }
  .status-card p { font-size: 12px; }

  #step-list li { padding: 6px 8px; font-size: 12px; }
  #trigger-list li { padding: 5px 8px; font-size: 11px; }

  footer {
    padding: 10px 14px 14px;
    max-height: none;
  }
  #log-list { max-height: 120px; overflow-y: auto; }
  #log-list li { font-size: 10px; }
}

@media (max-width: 480px) {
  .brand-text { display: none; }
  .brand { gap: 0; }
}

/* ===== 减少动画偏好 ===== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  .scan-line { display: none; }
}

/* ===== 焦点可见性 ===== */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}