/**
 * 学习页（learn.html）—— 课程清单式
 * 三级视图：课程清单 → 课程详情（章节） → 章节学习（知识卡）
 * 全部复用 variables.css / ui.css 既有令牌，深浅色自动适配。
 */

.learn-app {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 0 96px;
}

/* ============ 通用 ============ */
.learn-group-title {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 26px 0 12px;
  font-size: var(--font-size-sm);
  font-weight: 700;
  letter-spacing: var(--letter-spacing-wide);
  color: var(--color-text-secondary);
}
.learn-group-title::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--color-border);
}
.learn-empty {
  padding: 24px 0;
  text-align: center;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

/* ============ 日期 + 统计 ============ */
.learn-date {
  margin: 2px 2px 12px;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}
.learn-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  padding: 14px 0;
  border-radius: var(--card-radius);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-e1);
}
.learn-stat {
  position: relative;
  display: grid;
  justify-items: center;
  gap: 3px;
}
.learn-stat + .learn-stat::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--color-border);
}
.learn-stat-num {
  font-size: var(--font-size-xl);
  font-weight: 800;
  line-height: 1.1;
  color: var(--color-primary);
  letter-spacing: var(--letter-spacing-tight);
  font-variant-numeric: tabular-nums;
}
.learn-stat-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
}
/* 今日计划：可点击入口 */
.learn-stat.is-link {
  border: none;
  background: transparent;
  font-family: inherit;
  cursor: pointer;
  padding: 0;
}
.learn-stat.is-link .learn-stat-label { color: var(--color-primary); }
.learn-stat.is-link:active { transform: scale(0.97); }

/* ============ 每日一学（紫渐变主卡） ============ */
.learn-daily {
  position: relative;
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 14px;
  padding: 18px;
  border-radius: var(--card-radius);
  background-image: var(--cat-basic-grad);
  color: #fff;
  box-shadow: 0 10px 26px rgba(94, 106, 210, 0.26);
  cursor: pointer;
  overflow: hidden;
}
.learn-daily::after {
  content: '';
  position: absolute;
  right: -34px;
  top: -44px;
  width: 148px;
  height: 148px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.12);
}
.learn-daily.is-done {
  background-image: linear-gradient(135deg, #7C86E0, #A855F7);
}
.learn-daily-body {
  position: relative;
  z-index: 1;
  flex: 1;
  min-width: 0;
  display: grid;
  gap: 4px;
}
.learn-daily-cap {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: rgba(255, 255, 255, 0.82);
}
.learn-daily-title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: #fff;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.learn-daily-cta {
  position: relative;
  z-index: 1;
  flex: none;
  padding: 9px 16px;
  border-radius: var(--radius-full);
  background: #fff;
  color: var(--color-primary);
  font-size: var(--font-size-sm);
  font-weight: 700;
  white-space: nowrap;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
}

/* ============ 极简文字入口（章节自测 / 闯关挑战） ============ */
.learn-links {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 14px;
}
.learn-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  gap: 6px;
  padding: 11px 16px;
  border-radius: var(--radius-full);
  background: var(--gradient-brand-soft);
  border: 1px solid var(--color-border);
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
  transition: transform var(--duration-fast) var(--ease-tactile), border-color var(--duration-fast);
}
.learn-link { text-decoration: none; }
.learn-link:hover,
.learn-link:focus-visible {
  border-color: var(--color-primary);
  text-decoration: none;
}
.learn-link:active { transform: scale(0.97); }
.learn-link-arrow { font-size: var(--font-size-sm); }

/* ============ 课程列表 ============ */
.learn-courses { display: flex; flex-direction: column; gap: 12px; }

.learn-course {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 16px;
  border-radius: var(--card-radius);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-e1);
  cursor: pointer;
  transition: transform var(--duration-fast) var(--ease-tactile), border-color var(--duration-fast);
}
.learn-course:active { transform: scale(0.985); }
.learn-course:hover { border-color: var(--color-border-strong); }
.learn-course-ico {
  flex: none;
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  background: var(--icon-surface);
  color: var(--icon-fg);
}
.learn-course-ico svg { width: 22px; height: 22px; }
.learn-course-meta {
  flex: 1;
  min-width: 0;
  display: grid;
  gap: 3px;
}
.learn-course-name {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text-primary);
}
.learn-course-sub {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.learn-prog-bar {
  display: block;
  height: 7px;
  border-radius: var(--radius-full);
  background: var(--color-border-subtle);
  overflow: hidden;
}
.learn-prog-fill {
  display: block;
  height: 100%;
  border-radius: var(--radius-full);
  background: var(--gradient-brand);
  transition: width var(--duration-slow) var(--ease-smooth);
}
/* 选修课：响应式网格导航入口（仅图标 + 名称） */
.learn-elective-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.learn-elective {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding: 16px 8px;
  border-radius: var(--card-radius);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-e1);
  font-family: inherit;
  color: var(--color-text-primary);
  cursor: pointer;
  transition: transform var(--duration-fast) var(--ease-tactile), border-color var(--duration-fast);
}
.learn-elective:active { transform: scale(0.97); }
.learn-elective:hover { border-color: var(--color-border-strong); }
.learn-elective-ico {
  display: grid;
  place-items: center;
  color: var(--cat-maintain);
}
.learn-elective-ico svg { width: 30px; height: 30px; }
.learn-elective-name {
  font-size: var(--font-size-sm);
  font-weight: 600;
  text-align: center;
  line-height: 1.3;
}

/* 必修课：大卡片版式（图标 + 标题 + 副标题 + 底部进度条） */
.learn-course[data-kind="required"] {
  display: block;
  padding: 16px;
}
.learn-course-top { display: flex; align-items: center; gap: 14px; }
.learn-course[data-kind="required"] .learn-course-ico {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background-image: var(--cat-basic-grad);
  color: #fff;
}
.learn-course[data-kind="required"] .learn-course-ico svg { width: 24px; height: 24px; }
.learn-course[data-phase="home"] .learn-course-ico { background-image: var(--cat-practice-grad); }
.learn-course[data-phase="sparkles"] .learn-course-ico { background-image: linear-gradient(135deg, #60A5FA, #3B82F6); }
.learn-course[data-kind="required"] .learn-course-name { font-size: var(--font-size-base); font-weight: 700; }
.learn-course-bottom {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 14px;
}
.learn-course-bottom .learn-prog-bar { flex: 1; }
.learn-course-num {
  flex: none;
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  font-variant-numeric: tabular-nums;
}
.learn-course[data-phase="brain"] .learn-prog-fill { background-image: var(--cat-basic-grad); }
.learn-course[data-phase="home"] .learn-prog-fill { background-image: var(--cat-practice-grad); }
.learn-course[data-phase="sparkles"] .learn-prog-fill { background-image: var(--cat-maintain-grad); }

/* ============ 课程详情：Hero + 进度卡 ============ */
.learn-hero {
  position: relative;
  overflow: hidden;
  margin: 0 calc(-1 * var(--page-pad-x));
  padding: 22px var(--page-pad-x) 28px;
  background-image: var(--hero-grad);
  color: var(--hero-fg, #fff);
  border-radius: 0 0 var(--body-radius) var(--body-radius);
}
.learn-hero-cap {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: rgba(255, 255, 255, 0.82);
}
.learn-hero-title {
  margin-top: 6px;
  font-size: var(--font-size-2xl);
  font-weight: 800;
  letter-spacing: var(--letter-spacing-tight);
}
.learn-hero-sub {
  margin-top: 6px;
  font-size: var(--font-size-sm);
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.88);
}

.learn-prog-card {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: -18px;
  padding: 16px;
  border-radius: var(--card-radius);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-e1);
}
.learn-ring {
  --pct: 0;
  position: relative;
  flex: none;
  display: grid;
  place-items: center;
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: conic-gradient(var(--color-primary) calc(var(--pct) * 1%), var(--color-border-subtle) 0);
}
.learn-ring-inner {
  display: grid;
  place-items: center;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: var(--color-surface);
}
.learn-ring-num {
  font-size: var(--font-size-sm);
  font-weight: 800;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}
.learn-prog-info { min-width: 0; }
.learn-prog-info-title {
  font-size: var(--font-size-md);
  font-weight: 700;
  color: var(--color-text-primary);
}
.learn-prog-info-sub {
  margin-top: 3px;
  font-size: var(--font-size-sm);
  line-height: 1.5;
  color: var(--color-text-secondary);
}

/* ============ 章节列表 ============ */
.learn-sections { display: flex; flex-direction: column; gap: 10px; margin-top: 12px; }
.learn-section {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px;
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-e1);
  cursor: pointer;
}
.learn-section:active { transform: scale(0.99); }
.learn-dot {
  flex: none;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: var(--radius-full);
  font-size: var(--font-size-sm);
  font-weight: 700;
  background: var(--color-border-subtle);
  color: var(--color-text-secondary);
  font-variant-numeric: tabular-nums;
}
.learn-dot[data-state="done"] { background-image: var(--cat-maintain-grad); color: #fff; }
.learn-dot[data-state="doing"] { background-image: var(--cat-basic-grad); color: #fff; }
.learn-dot svg { width: 16px; height: 16px; }
.learn-section-meta { flex: 1; min-width: 0; display: grid; gap: 3px; }
.learn-section-name {
  font-size: var(--font-size-md);
  font-weight: 700;
  color: var(--color-text-primary);
}
.learn-section-sub {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.learn-quiz-btn {
  flex: none;
  padding: 5px 12px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border-strong);
  background: transparent;
  color: var(--color-text-secondary);
  font-family: inherit;
  font-size: var(--font-size-xs);
  font-weight: 600;
  cursor: pointer;
}
.learn-quiz-btn:hover { color: var(--color-primary); border-color: var(--color-primary); }

/* ============ 章节学习：知识卡流 ============ */
.learn-head { margin-top: 4px; }
.learn-head-title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-text-primary);
  letter-spacing: var(--letter-spacing-tight);
}
.learn-head-sub { margin-top: 4px; font-size: var(--font-size-sm); color: var(--color-text-secondary); }

.learn-cards { display: flex; flex-direction: column; gap: 10px; margin-top: 12px; }
.learn-card {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px;
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-e1);
  cursor: pointer;
}
.learn-card:active { transform: scale(0.99); }
.learn-card-ico {
  flex: none;
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
  background: var(--icon-surface);
  color: var(--icon-fg);
}
.learn-card-ico svg { width: 18px; height: 18px; }
.learn-card-meta { flex: 1; min-width: 0; }
.learn-card-title {
  display: block;
  font-size: var(--font-size-md);
  font-weight: 600;
  color: var(--color-text-primary);
  line-height: 1.4;
}
.learn-card-gist {
  display: -webkit-box;
  margin-top: 3px;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* 掌握度徽章 */
.learn-badge {
  flex: none;
  align-self: center;
  padding: 3px 9px;
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: 600;
  background: var(--color-border-subtle);
  color: var(--color-text-secondary);
  white-space: nowrap;
}
.learn-badge[data-lv="attempted"] { background: var(--tag-time-bg); color: var(--tag-time-fg); }
.learn-badge[data-lv="familiar"] { background: var(--tag-diff-bg); color: var(--tag-diff-fg); }
.learn-badge[data-lv="proficient"] { background: rgba(59, 130, 246, 0.14); color: var(--accent-blue); }
.learn-badge[data-lv="mastered"] { background: var(--tag-ok-bg); color: var(--tag-ok-fg); }

/* ============ 底部固定「继续 / 自测」 ============ */
.learn-continue {
  position: fixed;
  left: 50%;
  transform: translateX(-50%);
  bottom: calc(16px + var(--bottom-extra, 0px) + var(--vvb, 0px));
  z-index: 30;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-width: 260px;
  max-width: calc(100% - 32px);
  padding: 14px 26px;
  border: none;
  border-radius: var(--radius-full);
  background-image: var(--hero-grad);
  color: #fff;
  font-family: inherit;
  font-size: var(--font-size-md);
  font-weight: 700;
  box-shadow: var(--glow-primary);
  cursor: pointer;
}
.learn-continue:active { transform: translateX(-50%) scale(0.985); }
.learn-continue svg { width: 18px; height: 18px; }

/* ============ 响应式 ============ */
@media (min-width: 560px) {
  /* 选修网格：宽度足够时按可用宽度自适应列数（150px 起） */
  .learn-elective-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
}
@media (min-width: 769px) {
  .learn-daily { padding: 20px; }
}
@media (max-width: 768px) {
  .learn-app { padding: 0 0 88px; }
  .learn-daily-title { font-size: var(--font-size-base); }
}