/* ============ 教学任务互动网站 - 共享样式（浅色教学风格） ============ */
:root {
  --bg: #f4f6fa;
  --card: #ffffff;
  --text: #1e293b;
  --text-2: #64748b;
  --border: #e2e8f0;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --success: #16a34a;
  --success-dark: #15803d;
  --danger: #ef4444;
  --danger-light: #fee2e2;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(15, 23, 42, .08), 0 4px 14px rgba(15, 23, 42, .05);
  --shadow-lg: 0 10px 30px rgba(15, 23, 42, .12);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

.container { max-width: 860px; margin: 0 auto; padding: 28px 16px 60px; }

/* ---------- 页头 ---------- */
.page-header { text-align: center; padding: 26px 0 22px; }
.page-header h1 { font-size: 26px; font-weight: 700; letter-spacing: .5px; }
.page-header p { color: var(--text-2); margin-top: 6px; font-size: 14px; }

/* ---------- 卡片 ---------- */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
  margin-bottom: 16px;
}
.card-title { font-size: 17px; font-weight: 600; margin-bottom: 14px; }

/* ---------- 表单 ---------- */
.form-group { margin-bottom: 14px; }
.form-group label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 6px; }
.form-group label .optional { font-weight: 400; color: var(--text-2); font-size: 12px; }
.form-group input[type="text"],
.form-group input[type="number"],
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  font-family: inherit;
  background: #fff;
  color: var(--text);
  transition: border-color .15s, box-shadow .15s;
}
.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, .12);
}
.form-group textarea { min-height: 110px; resize: vertical; }

.form-row { display: flex; gap: 10px; }
.form-row .grow { flex: 1; }
.form-row .unit { width: 110px; flex-shrink: 0; }

.file-input-wrap {
  border: 1.5px dashed var(--border);
  border-radius: 8px;
  padding: 12px;
  background: #fafbfd;
  font-size: 13px;
  color: var(--text-2);
}
.file-input-wrap input[type="file"] { font-size: 13px; width: 100%; }
.file-selected { margin-top: 8px; font-size: 13px; color: var(--primary); display: none; }
.file-selected.show { display: block; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  border: none;
  border-radius: 10px;
  padding: 11px 22px;
  font-size: 15px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: transform .08s, box-shadow .15s, background .15s, opacity .15s;
  user-select: none;
}
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover:not(:disabled) { background: var(--primary-dark); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover:not(:disabled) { background: var(--success-dark); }
.btn-danger { background: var(--danger-light); color: var(--danger); }
.btn-danger:hover:not(:disabled) { background: #fecaca; }
.btn-ghost {
  background: #fff; color: var(--text); border: 1px solid var(--border);
}
.btn-ghost:hover:not(:disabled) { background: #f8fafc; }
.btn-sm { padding: 6px 14px; font-size: 13px; border-radius: 8px; }
.btn-lg { padding: 14px 34px; font-size: 16px; border-radius: 12px; }

/* 禁用态 */
.btn:disabled,
.btn.disabled {
  background: #e2e8f0 !important;
  color: #94a3b8 !important;
  border-color: #e2e8f0 !important;
  cursor: not-allowed;
  box-shadow: none;
  opacity: .9;
}

/* ---------- 任务卡片列表 ---------- */
.task-list { display: flex; flex-direction: column; gap: 12px; }
.task-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 16px 18px;
  cursor: pointer;
  transition: border-color .15s, box-shadow .15s, transform .1s;
  text-decoration: none;
  color: inherit;
}
.task-item:hover { border-color: var(--primary); box-shadow: var(--shadow-lg); transform: translateY(-1px); }
.task-main { min-width: 0; }
.task-name { font-size: 16px; font-weight: 600; margin-bottom: 4px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.task-meta { font-size: 13px; color: var(--text-2); display: flex; gap: 14px; flex-wrap: wrap; }
.task-actions { display: flex; gap: 8px; flex-shrink: 0; }

.badge {
  display: inline-block;
  padding: 2px 9px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}
.badge-blue { background: #dbeafe; color: #1d4ed8; }
.badge-green { background: #dcfce7; color: #15803d; }
.badge-gray { background: #f1f5f9; color: #64748b; }

/* ---------- 空状态 ---------- */
.empty {
  text-align: center;
  color: var(--text-2);
  padding: 48px 16px;
  font-size: 14px;
}
.empty .big { font-size: 40px; margin-bottom: 10px; }

/* ---------- 任务详情 ---------- */
.detail-section { margin-bottom: 20px; }
.detail-label { font-size: 13px; font-weight: 600; color: var(--text-2); margin-bottom: 6px; }
.detail-text { font-size: 15px; white-space: pre-wrap; word-break: break-word; }
.detail-meta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
  margin: 14px 0 6px;
}
.meta-box {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
}
.meta-box .label { font-size: 12px; color: var(--text-2); }
.meta-box .value { font-size: 16px; font-weight: 700; margin-top: 2px; }

/* ---------- 底部按钮区（已收到/已完成 状态机） ---------- */
.action-bar {
  position: sticky;
  bottom: 14px;
  display: flex;
  justify-content: center;
  gap: 16px;
  padding: 14px;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(6px);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--shadow-lg);
  margin-top: 8px;
}
.action-bar .btn { flex: 1; max-width: 220px; }

/* ---------- 弹窗 ---------- */
.modal-mask {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, .45);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 16px;
  animation: fadeIn .18s ease;
}
.modal {
  background: #fff;
  border-radius: 14px;
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 380px;
  padding: 24px;
  animation: popIn .2s ease;
}
.modal h3 { font-size: 17px; margin-bottom: 8px; }
.modal p { font-size: 14px; color: var(--text-2); margin-bottom: 16px; }
.modal .form-group { margin-bottom: 16px; }
.modal-actions { display: flex; gap: 10px; justify-content: flex-end; }

/* ---------- 统计表 ---------- */
.stats-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.stats-table th, .stats-table td { padding: 9px 12px; text-align: left; border-bottom: 1px solid var(--border); }
.stats-table th { font-size: 13px; color: var(--text-2); font-weight: 600; background: #f8fafc; }
.stats-table .ok { color: var(--success); font-weight: 600; }
.stats-table .none { color: #cbd5e1; }
.stats-summary { display: flex; gap: 10px; margin-bottom: 12px; flex-wrap: wrap; }

/* ---------- Toast ---------- */
#toast-box {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 200;
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
}
.toast {
  background: #1e293b;
  color: #fff;
  padding: 10px 20px;
  border-radius: 999px;
  font-size: 14px;
  box-shadow: var(--shadow-lg);
  animation: toastIn .25s ease;
  max-width: 90vw;
}
.toast.ok { background: var(--success); }
.toast.err { background: var(--danger); }

/* ---------- 首页入口 ---------- */
.entry-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
  margin-top: 10px;
}
.entry-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 40px 24px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--shadow);
  text-decoration: none;
  color: var(--text);
  transition: transform .12s, box-shadow .18s, border-color .18s;
}
.entry-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); border-color: var(--primary); }
.entry-card .icon { font-size: 44px; line-height: 1; }
.entry-card .title { font-size: 18px; font-weight: 700; }
.entry-card .desc { font-size: 13px; color: var(--text-2); text-align: center; }

/* ---------- 返回链接 ---------- */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 14px;
  color: var(--text-2);
  text-decoration: none;
  margin-bottom: 12px;
}
.back-link:hover { color: var(--primary); }

/* ---------- 动画 ---------- */
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes popIn { from { opacity: 0; transform: scale(.96); } to { opacity: 1; transform: scale(1); } }
@keyframes toastIn { from { opacity: 0; transform: translateY(-8px); } to { opacity: 1; transform: translateY(0); } }

@media (max-width: 560px) {
  .container { padding: 18px 12px 50px; }
  .task-item { flex-direction: column; align-items: stretch; }
  .task-actions { justify-content: flex-end; }
}