* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Segoe UI", Roboto, sans-serif;
}

body {
  background: #050507;
  color: #eee;
  overflow: hidden;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 24px;
  background: linear-gradient(90deg, #0f2a34, #3a1527);
  border-bottom: 1px solid #222;
}

.logo {
  font-size: 18px;
  letter-spacing: 2px;
  font-weight: 600;
}

.nav-right > button {
  padding: 7px 18px;
  border-radius: 99px;
  border: none;
  background: #fff;
  color: #111;
  font-weight: 600;
  cursor: pointer;
}

main {
  flex: 1;
  display: grid;
  grid-template-columns: 240px 1fr;
}

aside {
  background: #0c0c12;
  padding: 20px 16px;
  border-right: 1px solid #1f1f2a;
  overflow-y: auto;
}

.control-group {
  margin-bottom: 22px;
}

.control-group h4 {
  color: #888;
  font-size: 12px;
  margin-bottom: 10px;
  letter-spacing: 1px;
}

.btn {
  display: block;
  width: 100%;
  padding: 9px;
  margin-bottom: 8px;
  background: #14141c;
  color: #ddd;
  border: 1px solid #2a2a38;
  border-radius: 6px;
  cursor: pointer;
  transition: 0.2s;
}

.btn:hover {
  border-color: #44bbff;
  color: #9ad7ff;
}

.btn.active {
  background: #142535;
  border-color: #44bbff;
  color: #9ad7ff;
}

.btn.danger:hover {
  border-color: #ff6666;
  color: #ffb3b3;
}

input[type="range"] {
  width: 100%;
  accent-color: #44bbff;
}

.canvas-wrap {
  position: relative;
  background: #000;
}

#canvas {
  width: 100%;
  height: 100%;
  display: block;
  cursor: default;
}

#video {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 180px;
  border-radius: 8px;
  opacity: 0.35;
  transform: scaleX(-1);
  border: 1px solid #333;
}

.status {
  position: absolute;
  top: 16px;
  left: 16px;
  background: rgba(0, 0, 0, 0.55);
  padding: 8px 14px;
  border-radius: 6px;
  font-size: 12px;
  color: #77ddff;
}

.hint {
  position: absolute;
  left: 16px;
  bottom: 16px;
  background: rgba(0, 0, 0, 0.55);
  padding: 8px 14px;
  border-radius: 6px;
  font-size: 12px;
  color: #9ad7ff;
}

/* 前置交互界面 */
.intro-overlay {
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at center, rgba(20, 40, 60, 0.35), rgba(0, 0, 0, 0.92) 70%);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
  transition: opacity 0.6s ease;
}

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

.intro-box {
  text-align: center;
  color: #cfe8ff;
}

.intro-box h1 {
  font-size: 44px;
  font-weight: 300;
  letter-spacing: 18px;
  margin-bottom: 12px;
  color: #fff;
}

.intro-sub {
  font-size: 13px;
  letter-spacing: 4px;
  color: #88a;
  margin-bottom: 30px;
}

.intro-box button {
  background: transparent;
  border: 1px solid #44bbff;
  color: #9ad7ff;
  padding: 14px 36px;
  font-size: 14px;
  letter-spacing: 6px;
  border-radius: 99px;
  cursor: pointer;
  transition: 0.3s;
}

.intro-box button:hover {
  background: rgba(68, 187, 255, 0.12);
  color: #fff;
  border-color: #9ad7ff;
  box-shadow: 0 0 24px rgba(68, 187, 255, 0.35);
}

.intro-note {
  margin-top: 30px;
  font-size: 12px;
  letter-spacing: 3px;
  color: #557;
}