/* ============================================================
   班级小岛 · 设计系统实现（设计规范 v1.3）
   护眼基调：暖白底 / 深蓝灰字 / 高饱和只点缀 / 大字 / 无频闪
   ============================================================ */

:root {
  --color-primary: #35B5A0;
  --color-primary-dark: #2A9A87;
  --color-primary-soft: #E4F5F1;
  --color-sky: #6EC6E8;
  --color-sand: #FBF6EC;
  --color-coral: #FF9E7D;
  --color-sun: #FFC94D;
  --color-ink: #33475B;
  --color-ink-light: #6B7C8F;
  --color-success: #4CAF7D;
  --color-success-soft: #E6F4EC;
  --color-retry: #93A8BC;
  --color-retry-bg: #EDF3F8;
  --color-card: #FFFDF8;
  --color-line: #E8E2D5;
  --color-grape: #9B8CFF;
  --color-berry: #FF7FA5;

  --radius-card: 20px;
  --radius-btn: 16px;
  --radius-sm: 12px;
  --shadow-card: 0 2px 12px rgba(51, 71, 91, .08);
  --shadow-pop: 0 6px 24px rgba(51, 71, 91, .14);
  --font-stack: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --content-max: 1080px;
  --student-max: 640px;
}

/* ---------- 基础 ---------- */
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font-stack);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-ink);
  background: var(--color-sand);
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3 { font-weight: 600; line-height: 1.4; margin: 0 0 .5em; }
h1 { font-size: 22px; }
h2 { font-size: 20px; }
h3 { font-size: 18px; }
p { margin: 0 0 1em; }
a { color: var(--color-primary-dark); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; vertical-align: middle; }
:focus-visible { outline: 3px solid var(--color-primary); outline-offset: 2px; border-radius: 6px; }

.muted { color: var(--color-ink-light); }
.small { font-size: 14px; }
.center { text-align: center; }
.row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.spread { display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; }
.stack > * + * { margin-top: 16px; }

/* ---------- 按钮（触摸目标 ≥48px） ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 48px; padding: 0 22px;
  font-family: inherit; font-size: 16px; font-weight: 600; line-height: 1.2;
  border-radius: var(--radius-btn); border: 2px solid transparent;
  cursor: pointer; text-decoration: none; transition: background .15s ease-out, transform .05s ease-out;
}
.btn:hover { text-decoration: none; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--color-primary); color: #fff; }
.btn-primary:hover { background: var(--color-primary-dark); }
.btn-secondary { background: var(--color-card); color: var(--color-primary-dark); border-color: var(--color-primary); }
.btn-secondary:hover { background: var(--color-primary-soft); }
.btn-ghost { background: transparent; color: var(--color-ink-light); min-height: 40px; padding: 0 12px; }
.btn-ghost:hover { color: var(--color-ink); background: rgba(51,71,91,.05); }
.btn-danger-soft { background: var(--color-retry-bg); color: var(--color-ink); border-color: var(--color-retry); }
.btn-sm { min-height: 40px; font-size: 14px; padding: 0 14px; border-radius: var(--radius-sm); }
.btn-block { width: 100%; }
.btn[disabled], .btn.is-disabled { opacity: .4; cursor: not-allowed; pointer-events: none; }
/* 学生端主按钮更大 */
.role-student .btn { min-height: 52px; font-size: 18px; }

/* ---------- 卡片 ---------- */
.card {
  background: var(--color-card);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  padding: 24px;
}
.card + .card { margin-top: 20px; }
.card-title { font-size: 18px; font-weight: 600; margin: 0 0 16px; }
.card-pad-sm { padding: 16px; }

/* ---------- 表单 ---------- */
.field { margin-bottom: 18px; }
.field-label { display: block; font-size: 15px; font-weight: 600; margin-bottom: 6px; color: var(--color-ink); }
.field-hint { font-size: 13px; color: var(--color-ink-light); margin-top: 4px; }
.input, .select, .textarea {
  width: 100%; min-height: 48px; padding: 10px 14px;
  font-family: inherit; font-size: 16px; color: var(--color-ink);
  background: var(--color-card); border: 2px solid var(--color-line); border-radius: var(--radius-sm);
  transition: border-color .15s ease-out;
}
.input:focus, .select:focus, .textarea:focus { border-color: var(--color-primary); outline: none; }
.textarea { min-height: 120px; resize: vertical; line-height: 1.6; }
.input-num { letter-spacing: 2px; font-size: 20px; text-align: center; }
.form-inline { display: flex; gap: 10px; align-items: flex-end; flex-wrap: wrap; }
.form-inline .field { margin-bottom: 0; flex: 1; min-width: 140px; }

/* ---------- 提示条（无红黑） ---------- */
.flash { padding: 12px 16px; border-radius: var(--radius-sm); margin-bottom: 16px; font-size: 15px; border: 1px solid transparent; }
.flash-ok { background: var(--color-success-soft); color: #2f7d54; border-color: #bfe3cd; }
.flash-info { background: var(--color-primary-soft); color: var(--color-primary-dark); border-color: #bfe6dd; }
.flash-retry { background: var(--color-retry-bg); color: var(--color-ink); border-color: #cdd9e4; }

/* ---------- 徽章 / 标签 / chip ---------- */
.chip { display: inline-flex; align-items: center; gap: 6px; padding: 6px 12px; border-radius: 999px; font-size: 14px; font-weight: 600; background: var(--color-primary-soft); color: var(--color-primary-dark); }
.chip-island { background: var(--color-card); border: 1px solid var(--color-line); color: var(--color-ink); }
.tag { display: inline-block; padding: 3px 10px; border-radius: 999px; font-size: 13px; font-weight: 600; }
.tag-ok { background: var(--color-success-soft); color: #2f7d54; }
.tag-warn { background: #FFEFE6; color: #C86A4A; }
.tag-muted { background: var(--color-retry-bg); color: var(--color-ink-light); }

/* ---------- 表格 ---------- */
.table-wrap { overflow-x: auto; border-radius: var(--radius-sm); border: 1px solid var(--color-line); }
.table { width: 100%; border-collapse: collapse; font-size: 15px; background: var(--color-card); }
.table th, .table td { padding: 12px 14px; text-align: left; border-bottom: 1px solid var(--color-line); vertical-align: middle; }
.table th { background: var(--color-sand); font-weight: 600; color: var(--color-ink-light); font-size: 14px; white-space: nowrap; }
.table tr:last-child td { border-bottom: none; }
.table tr:hover td { background: rgba(53,181,160,.04); }

/* ---------- 进度 / 能量条 ---------- */
.bar { height: 14px; border-radius: 999px; background: var(--color-retry-bg); overflow: hidden; }
.bar-fill { height: 100%; border-radius: 999px; background: linear-gradient(90deg, var(--color-primary), var(--color-sky)); transition: width .3s ease-out; }

/* ============================================================
   布局：管理 / 老师（侧边栏 + 内容）
   ============================================================ */
.app-shell { display: flex; min-height: 100vh; }
.sidebar {
  width: 232px; flex-shrink: 0; background: var(--color-card);
  border-right: 1px solid var(--color-line); padding: 20px 14px;
  display: flex; flex-direction: column; position: sticky; top: 0; height: 100vh;
}
.brand { display: flex; align-items: center; gap: 10px; padding: 6px 10px 18px; }
.brand-mark { display: block; }
.brand-name { font-size: 18px; font-weight: 600; color: var(--color-ink); }
.nav { display: flex; flex-direction: column; gap: 4px; flex: 1; }
.nav-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 14px; border-radius: var(--radius-sm); font-size: 16px; font-weight: 500;
  color: var(--color-ink); text-decoration: none; min-height: 48px;
}
.nav-item:hover { background: var(--color-primary-soft); text-decoration: none; }
.nav-item.is-active { background: var(--color-primary); color: #fff; font-weight: 600; }
.nav-item.is-disabled { color: var(--color-ink-light); opacity: .6; cursor: default; }
.nav-item.is-disabled:hover { background: transparent; }
.soon { font-size: 11px; font-weight: 600; background: var(--color-retry-bg); color: var(--color-ink-light); padding: 2px 6px; border-radius: 6px; }
.sidebar-foot { border-top: 1px solid var(--color-line); padding-top: 14px; margin-top: 10px; }
.who { font-size: 15px; font-weight: 600; padding: 0 10px 6px; }
.logout-link { display: inline-block; padding: 6px 10px; font-size: 14px; color: var(--color-ink-light); }
.logout-link:hover { color: var(--color-coral); }
.logout-form { display: inline; margin: 0; }
button.logout-link { background: none; border: none; font-family: inherit; cursor: pointer; }
button.logout-link:hover { text-decoration: underline; }

.app-main { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.topbar { padding: 22px 32px 6px; }
.topbar-title { font-size: 24px; margin: 0; }
.content { padding: 16px 32px 48px; max-width: var(--content-max); width: 100%; }

/* ============================================================
   布局：学生（移动优先，单列居中）
   ============================================================ */
.role-student { font-size: 18px; }
.student-top {
  display: flex; justify-content: space-between; align-items: center;
  padding: 14px 16px; max-width: var(--student-max); margin: 0 auto; width: 100%;
}
.student-main { max-width: var(--student-max); margin: 0 auto; padding: 8px 16px 48px; width: 100%; }
.role-student .card { padding: 24px; }

/* ============================================================
   布局：登录 / _plain_（居中卡片）
   ============================================================ */
.layout-plain { background: linear-gradient(180deg, #7ED6F2 0%, #B8F0E8 46%, var(--color-sand) 46%, var(--color-sand) 100%); min-height: 100vh; }
.plain-main { max-width: 460px; margin: 0 auto; padding: 48px 16px; width: 100%; }
.auth-card { background: var(--color-card); border-radius: var(--radius-card); box-shadow: var(--shadow-pop); padding: 32px 28px; border: 1px solid var(--color-line); }
.auth-brand { text-align: center; margin-bottom: 24px; }
.auth-brand img { width: 64px; height: 64px; }
.auth-brand h1 { font-size: 26px; margin: 10px 0 4px; }
.auth-brand p { color: var(--color-ink-light); font-size: 15px; margin: 0; }
.auth-tabs { display: flex; gap: 8px; margin-bottom: 22px; background: var(--color-sand); padding: 6px; border-radius: var(--radius-sm); }
.auth-tab { flex: 1; text-align: center; padding: 10px; border-radius: 10px; font-size: 15px; font-weight: 600; color: var(--color-ink-light); cursor: pointer; border: none; background: transparent; min-height: 44px; }
.auth-tab.is-active { background: var(--color-card); color: var(--color-primary-dark); box-shadow: var(--shadow-card); }
.auth-panel { display: none; }
.auth-panel.is-active { display: block; }
.auth-foot { text-align: center; margin-top: 18px; font-size: 13px; color: var(--color-ink-light); }

/* ============================================================
   老师端：课节勾选
   ============================================================ */
.subject-block { margin-bottom: 24px; }
.subject-head { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.subject-dot { width: 12px; height: 12px; border-radius: 50%; }
.dot-math { background: var(--color-primary); }
.dot-chinese { background: var(--color-sky); }
.dot-moral { background: var(--color-coral); }
.unit-name { font-size: 14px; color: var(--color-ink-light); margin: 14px 0 8px; font-weight: 600; }
.lesson-list { display: flex; flex-direction: column; gap: 10px; }
.lesson-check {
  display: flex; align-items: center; gap: 14px; padding: 14px 16px;
  background: var(--color-card); border: 2px solid var(--color-line); border-radius: var(--radius-sm);
  cursor: pointer; min-height: 56px; transition: border-color .15s ease-out, background .15s ease-out;
}
.lesson-check:hover { border-color: var(--color-primary); }
.lesson-check.is-checked { border-color: var(--color-primary); background: var(--color-primary-soft); }
.lesson-check input { width: 24px; height: 24px; accent-color: var(--color-primary); flex-shrink: 0; cursor: pointer; }
.lesson-check .lesson-title { flex: 1; font-size: 16px; font-weight: 500; }
.lesson-check .lesson-meta { display: flex; gap: 8px; align-items: center; }

/* ---------- 聚合统计卡 ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 16px; }
.stat-card { background: var(--color-card); border: 1px solid var(--color-line); border-radius: var(--radius-card); padding: 22px; text-align: center; box-shadow: var(--shadow-card); }
.stat-num { font-size: 40px; font-weight: 700; color: var(--color-primary-dark); line-height: 1.1; }
.stat-label { font-size: 15px; color: var(--color-ink-light); margin-top: 6px; }

/* ---------- 空状态 ---------- */
.empty { text-align: center; padding: 40px 20px; color: var(--color-ink-light); }
.empty img { width: 80px; height: 80px; opacity: .8; margin-bottom: 12px; }

/* ---------- 工具 ---------- */
.mt-0 { margin-top: 0; } .mb-0 { margin-bottom: 0; } .mt-16 { margin-top: 16px; } .mt-24 { margin-top: 24px; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.divider { height: 1px; background: var(--color-line); margin: 20px 0; border: none; }
.code-pill { font-family: ui-monospace, "SFMono-Regular", Consolas, monospace; background: var(--color-sand); border: 1px solid var(--color-line); padding: 2px 10px; border-radius: 8px; font-size: 15px; letter-spacing: 1px; }

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  .app-shell { flex-direction: column; }
  .sidebar { width: 100%; height: auto; position: static; flex-direction: row; align-items: center; flex-wrap: wrap; gap: 8px; border-right: none; border-bottom: 1px solid var(--color-line); padding: 12px; }
  .brand { padding: 0 8px 0 0; }
  .nav { flex-direction: row; flex-wrap: wrap; flex: 1; }
  .nav-item { padding: 8px 12px; min-height: 40px; font-size: 15px; }
  .sidebar-foot { border-top: none; padding-top: 0; margin-top: 0; display: flex; align-items: center; gap: 8px; }
  .who { padding: 0; }
  .topbar { padding: 16px 16px 4px; }
  .content { padding: 12px 16px 40px; }
  .grid-2 { grid-template-columns: 1fr; }
}

/* ---------- 无障碍：减弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}