:root {
  --bg: #f6f7fb;
  --card: #ffffff;
  --text: #2b3147;
  --muted: #8b93a8;
  --primary: #ff7a59;
  --primary-dark: #f25f3d;
  --soft: #eef1f8;
  --border: #e5e8f0;
  --radius-lg: 22px;
  --radius-md: 14px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px rgba(40, 50, 90, 0.08);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;
  -webkit-tap-highlight-color: transparent;
  overscroll-behavior: none;
}

body {
  min-height: 100vh;
  background:
    radial-gradient(1200px 600px at 10% -10%, #ffe9df 0%, transparent 60%),
    radial-gradient(900px 500px at 100% 0%, #e6f0ff 0%, transparent 60%),
    var(--bg);
}

.app {
  max-width: 880px;
  margin: 0 auto;
  padding: 24px 16px 40px;
}

.head {
  text-align: center;
  margin-bottom: 18px;
}

.head h1 {
  margin: 0 0 6px;
  font-size: 30px;
  letter-spacing: 1px;
}

.head .hint {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
}

/* 画布舞台 */
.stage {
  position: relative;
  width: 100%;
  max-width: 720px;
  margin: 0 auto;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: #fff;
  box-shadow: var(--shadow);
  touch-action: none; /* 关键：禁止浏览器默认触摸行为，避免页面滚动干扰 */
  user-select: none;
  -webkit-user-select: none;
}

.stage canvas {
  display: block;
  width: 100%;
  height: auto;
  /* 两层叠加：底图彩色，顶层灰度覆盖 */
}

#board { position: relative; z-index: 1; }
#overlay {
  position: absolute;
  inset: 0;
  z-index: 2;
  cursor: crosshair;
}

/* 工具栏 */
.tools {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: space-between;
  align-items: center;
  margin: 18px auto 0;
  max-width: 720px;
  padding: 14px 16px;
  background: var(--card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.tool-group {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 1 1 280px;
  min-width: 0;
}

.tool-label {
  color: var(--muted);
  font-size: 14px;
  white-space: nowrap;
}

.sizes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  flex: 1;
  min-width: 0;
}

.size-dot {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 48px;
  background: var(--soft);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  padding: 0;
  transition: border-color 0.15s, background 0.15s;
}

.size-dot:hover { background: #e6eaf5; }
.size-dot.active {
  border-color: var(--primary);
  background: #fff5f1;
}

.size-dot .d {
  display: block;
  background: var(--text);
  border-radius: 50%;
}
.d-s { width: min(14px, 60%); height: min(14px, 60%); }
.d-m { width: min(22px, 60%); height: min(22px, 60%); }
.d-l { width: min(32px, 60%); height: min(32px, 60%); }

.btn {
  appearance: none;
  border: 0;
  font-size: 15px;
  font-weight: 600;
  padding: 12px 18px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: transform 0.05s, background 0.15s, box-shadow 0.15s;
  white-space: nowrap;
}

.btn:active { transform: translateY(1px); }

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 4px 12px rgba(255, 122, 89, 0.35);
}
.btn-primary:hover { background: var(--primary-dark); }

.btn-soft {
  background: var(--soft);
  color: var(--text);
}
.btn-soft:hover { background: #e6eaf5; }

/* 缩略图画廊 */
.gallery {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin: 16px auto 0;
  max-width: 720px;
  padding: 14px 16px;
  background: var(--card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.thumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  flex: 1;
}

.thumb {
  width: 64px;
  height: 68px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  cursor: pointer;
  border: 3px solid transparent;
  background: var(--soft);
  padding: 0;
  transition: border-color 0.15s, transform 0.05s;
}

.thumb:hover { transform: translateY(-1px); }
.thumb.active {
  border-color: var(--primary);
}

.thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  /* 缩略图也显示灰度态，与画布一致 */
  filter: grayscale(1) brightness(1.08);
}

/* 响应式 */
@media (max-width: 520px) {
  .head h1 { font-size: 24px; }
  .head .hint { font-size: 13px; }
  .tools { padding: 12px; gap: 10px; }
  .tool-group { flex: 1 1 100%; justify-content: space-between; }
  .btn { padding: 11px 14px; font-size: 14px; }
  .size-dot { height: 42px; }
  .thumb { width: 56px; height: 60px; }
}