:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --accent: #2563eb;
  --border: #e5e7eb;
  --code-bg: #f3f4f6;
  --max-width: 800px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --text: #f8fafc;
    --accent: #38bdf8;
    --border: #334155;
    --code-bg: #1e293b;
  }
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  margin: 0;
  padding: 2rem 1rem;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
}

h1, h2, h3 { color: var(--accent); margin-top: 2rem; }
img { max-width: 100%; height: auto; border-radius: 8px; border: 1px solid var(--border); margin: 1rem 0; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.walkthrough-p { margin-bottom: 2rem; border-bottom: 1px solid var(--border); padding-bottom: 1rem; }
.walkthrough-main-img { display: block; margin: 1.5rem auto; }

/* 新增 Card 样式 */
.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  margin: 1.5rem 0;
  box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

/* 新增 Well 样式 */
.well {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.5rem;
  margin: 1.5rem 0;
  position: relative;
  overflow: hidden;
}

.well::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--accent);
  opacity: 0.5;
}

/* 折叠交互支持 */
.well h3 {
  margin: 0;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  user-select: none;
  font-size: 1.25rem;
}

.well h3::before {
  content: '▶';
  font-size: 0.8rem;
  color: var(--accent);
  transition: transform 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  display: inline-block;
}

/* 状态切换：展开 */
.well h3.expanded::before {
  transform: rotate(90deg);
}

/* 状态切换：收起时隐藏内容 (排除 h3 自身) */
.well h3:not(.expanded) ~ * {
  display: none;
}

/* 优化紧凑布局：当展开时增加下方距离 */
.well h3.expanded {
  margin-bottom: 1.2rem;
}

/* 响应式调整 */
@media (max-width: 640px) {
  body { padding: 1rem; }
  .card, .well { padding: 1rem; }
}