/* ============================================================================
   VibeHub 课程站共享样式 · 1/lesson.css
   统一视觉世界：The Card Catalog（卡片图鉴）
   需在共享 ../style.css 之后引入（依赖其设计令牌与明暗主题）
   引用：../style.css + lesson.css
   ========================================================================== */

/* ---------- 页面骨架 ---------- */
.lesson-page { min-height: 100vh; padding: 2rem 0; }
.lesson-wrap, .container { max-width: 750px; margin: 0 auto; padding: 0 24px; }
@media (max-width: 760px) { .lesson-page { padding: 1.25rem 0; } .lesson-wrap, .container { padding: 0 16px; } }

/* ---------- 面包屑 ---------- */
.breadcrumb {
  display: flex; flex-wrap: wrap; align-items: center; gap: 6px;
  color: var(--text-3); font-size: 13.5px; margin-bottom: 24px;
}
.breadcrumb a { color: var(--brand); text-decoration: none; }
.breadcrumb a:hover { text-decoration: underline; }

/* ---------- 页头 ---------- */
.lesson-head h1, h1 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 750; letter-spacing: -.02em; line-height: 1.25;
  margin-bottom: 8px;
}
.lesson-head .subtitle, .subtitle { color: var(--text-2); font-size: 15px; margin-bottom: 28px; }

/* ---------- 教学卡片 ---------- */
.card, .lesson-card-box {
  background: var(--bg); border: 1px solid var(--border-light); border-radius: var(--radius-lg);
  padding: 28px; margin-bottom: 24px; box-shadow: var(--shadow-card);
}
.card h2, .lesson-card-box h2 {
  font-size: 20px; font-weight: 700; margin-bottom: 16px;
  display: flex; align-items: center; gap: 8px;
}
.card p, .lesson-card-box p { color: var(--text-2); line-height: 1.85; margin-bottom: 12px; font-size: 15px; }
.card p strong, .lesson-card-box p strong { color: var(--text); font-weight: 650; }
.card ul, .card ol, .lesson-card-box ul, .lesson-card-box ol { margin: 0 0 12px 1.2rem; color: var(--text-2); line-height: 1.8; }
.card li, .lesson-card-box li { margin-bottom: 4px; }
.card code, .lesson-card-box code {
  font-family: var(--mono); font-size: 13px; background: var(--bg-demo);
  padding: 2px 6px; border-radius: 5px; color: var(--text);
}
@media (max-width: 760px) { .card, .lesson-card-box { padding: 20px 18px; } }

/* ---------- 强调块 ---------- */
.highlight {
  background: var(--brand-light); border-left: 3px solid var(--brand);
  padding: 16px 20px; border-radius: 0 8px 8px 0; margin: 16px 0;
  color: var(--text-2); line-height: 1.75; font-size: 14.5px;
}
.highlight strong { color: var(--brand); }

/* ---------- 对比块 ---------- */
.comparison { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 16px 0; }
@media (max-width: 640px) { .comparison { grid-template-columns: 1fr; } }
.comparison > div {
  padding: 16px 18px; border-radius: var(--radius); font-size: 14px; line-height: 1.7;
}
.comparison h4 { margin-bottom: 8px; font-weight: 650; }
.col-good { background: color-mix(in srgb, #16a34a 8%, var(--bg)); border: 1px solid color-mix(in srgb, #16a34a 30%, var(--border)); }
.col-good h4 { color: #16a34a; }
.col-bad { background: color-mix(in srgb, #e5484d 8%, var(--bg)); border: 1px solid color-mix(in srgb, #e5484d 30%, var(--border)); }
.col-bad h4 { color: #e5484d; }

/* ---------- 下一课 ---------- */
.next-link {
  display: flex; align-items: center; justify-content: center; gap: 6px;
  text-align: center; margin-top: 8px; padding: 16px;
  background: var(--brand); color: #fff; text-decoration: none;
  border-radius: var(--radius); font-size: 16px; font-weight: 600;
  transition: background .15s, transform .15s;
}
.next-link:hover { background: var(--brand-2); transform: translateY(-2px); }
.next-link:focus-visible { outline: none; box-shadow: 0 0 0 3px var(--brand-light); }

/* ---------- SVG 图标引用规范 ---------- */
.ic {
  width: 1em; height: 1em;
  display: inline-block;
  vertical-align: -0.15em;
  flex-shrink: 0;
}
.ic-lg { width: 1.6em; height: 1.6em; vertical-align: -0.3em; }
.ic-2x { width: 2em; height: 2em; vertical-align: -0.4em; }
/* demo 步骤容器（原 .emoji div）保持居中布局 */
.emoji { display: grid; place-items: center; }
.emoji .ic { width: 2.5rem; height: 2.5rem; }

/* 概念序号（原 1️⃣2️⃣3️⃣） */
.num {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 1.5em; height: 1.5em; padding: 0 .3em;
  background: var(--brand-light); color: var(--brand);
  border-radius: 6px; font-weight: 700; font-size: .85em;
  margin-right: .25em;
}

/* ---------- 课程首页：地图 / 层级 ---------- */
.map { display: flex; flex-direction: column; gap: 24px; margin-bottom: 32px; }
.lesson-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; }
.lesson-card {
  background: var(--bg); border: 1px solid var(--border-light); border-radius: var(--radius);
  padding: 20px; cursor: pointer; transition: transform .15s, box-shadow .15s, border-color .15s;
  text-decoration: none; color: inherit; display: block; box-shadow: var(--shadow-card);
}
.lesson-card:hover {
  border-color: var(--border-hover); transform: translateY(-2px); box-shadow: var(--shadow-float);
}
.lesson-card .icon { font-size: 28px; margin-bottom: 8px; display: flex; align-items: center; }
.lesson-card .icon .ic { width: 1.6em; height: 1.6em; vertical-align: baseline; }
.lesson-card .tag { display: inline-flex; align-items: center; gap: 4px; }
.lesson-card h3 { font-size: 16px; font-weight: 650; margin-bottom: 6px; }
.lesson-card p { font-size: 13.5px; color: var(--text-2); line-height: 1.5; }
.lesson-card .tag {
  display: inline-block; padding: 3px 10px; border-radius: 99px;
  font-size: 12px; margin-top: 12px; background: var(--bg-soft); color: var(--text-3);
}
.lesson-card.done { border-color: color-mix(in srgb, #16a34a 50%, var(--border)); }
.lesson-card.done .tag { background: color-mix(in srgb, #16a34a 12%, transparent); color: #16a34a; }
.lesson-card.locked { opacity: .4; pointer-events: none; }
.legend { display: flex; gap: 24px; justify-content: center; margin-top: 8px; font-size: 13.5px; color: var(--text-3); }
.legend span { display: flex; align-items: center; gap: 6px; }
.dot { width: 10px; height: 10px; border-radius: 50%; }
.dot.green { background: #4ade80; }
.dot.yellow { background: #facc15; }
.dot.orange { background: #fb923c; }
.dot.red { background: #f87171; }