:root {
  --green: #0C5F3E;        /* 深绿 (取自校徽) */
  --green-dark: #084a30;
  --green-light: #e8f3ee;
  --orange: #E87722;       /* 橙色 (取自校徽) */
  --orange-dark: #c96418;
  --grey-bg: #f5f6f5;
  --text: #2b2b2b;
  --muted: #7a7a7a;
  --danger: #c0392b;
  --radius: 10px;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: "Segoe UI", "Microsoft YaHei", "微软雅黑", Arial, sans-serif;
  background: var(--grey-bg);
  color: var(--text);
  line-height: 1.6;
}
.wrap { max-width: 1060px; margin: 0 auto; padding: 0 16px; }

/* ---------- 页头 ---------- */
.site-header { background: #fff; border-bottom: 4px solid var(--green); }
.header-inner { display: flex; align-items: center; gap: 18px; padding: 14px 16px; flex-wrap: wrap; }
.logo { height: 58px; max-width: 220px; object-fit: contain; }
.site-title { font-size: 22px; font-weight: 700; color: var(--green); }
.site-subtitle { font-size: 16px; color: var(--orange); font-weight: 600; }
.site-footer { text-align: center; color: var(--muted); font-size: 13px; padding: 26px 0; }

/* ---------- 通用元素 ---------- */
h1, h2, h3 { color: var(--green); }
a { color: var(--green); }
.panel { background: #fff; border-radius: var(--radius); padding: 22px; margin: 18px 0;
  box-shadow: 0 1px 4px rgba(0,0,0,.08); }
.btn {
  display: inline-block; padding: 9px 20px; border-radius: 6px; border: none; cursor: pointer;
  background: var(--green); color: #fff; text-decoration: none; font-size: 15px; text-align: center;
}
.btn:hover { background: var(--green-dark); }
.btn-orange { background: var(--orange); } .btn-orange:hover { background: var(--orange-dark); }
.btn-danger { background: var(--danger); } .btn-danger:hover { background: #96281b; }
.btn-outline { background: #fff; color: var(--green); border: 1.5px solid var(--green); }
.btn-outline:hover { background: var(--green-light); }
.btn-sm { padding: 4px 12px; font-size: 13px; }

table.list { width: 100%; border-collapse: collapse; margin: 12px 0; }
table.list th, table.list td { padding: 9px 10px; border: 1px solid #dde3e0; text-align: left; }
table.list th { background: var(--green); color: #fff; font-weight: 600; white-space: nowrap; }
table.list tr:nth-child(even) td { background: #f4f8f6; }

.flash { padding: 12px 16px; border-radius: 8px; margin: 14px 0; }
.flash-ok { background: #e8f6ec; border: 1px solid #9ed3ae; color: #1d6b34; }
.flash-err { background: #fdeceb; border: 1px solid #f0b5b0; color: #a93226; }
.muted { color: var(--muted); }

label.field { display: block; margin: 14px 0 4px; font-weight: 600; }
input[type=text], input[type=password], input[type=time], input[type=number], select {
  padding: 9px 10px; border: 1.5px solid #c9d4ce; border-radius: 6px; font-size: 15px;
  max-width: 100%; background: #fff;
}
input[type=text]:focus, select:focus, input[type=password]:focus { border-color: var(--green); outline: none; }

/* ---------- 教师卡片 ---------- */
.teacher-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 16px; margin: 16px 0; }
.teacher-card { background: #fff; border: 2px solid #e2e8e4; border-radius: var(--radius);
  padding: 14px 10px; text-align: center; text-decoration: none; color: var(--text);
  transition: border-color .15s, transform .15s; display: block; }
.teacher-card:hover { border-color: var(--orange); transform: translateY(-3px); }
.teacher-card img { width: 96px; height: 96px; border-radius: 50%; object-fit: cover;
  border: 3px solid var(--green-light); background: #eee; }
.teacher-card .t-name { font-weight: 700; color: var(--green); margin-top: 8px; font-size: 16px; }
.teacher-card .t-subject { font-size: 13px; color: var(--muted); }
.badge { display: inline-block; font-size: 11px; padding: 2px 8px; border-radius: 10px; margin-top: 6px; }
.badge-foreign { background: #fdf1e5; color: var(--orange-dark); border: 1px solid #f2c9a0; }

/* ---------- 时段选择 ---------- */
.slot-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 10px; margin: 10px 0; }
.slot { border: 1.5px solid #d5ddd8; border-radius: 8px; padding: 10px 12px; background: #fff; cursor: pointer; }
.slot:hover { border-color: var(--green); }
.slot input { margin-right: 8px; }
.slot-booked { background: #f0f0f0; border-color: #ddd; color: #888; cursor: not-allowed; }
.slot-booked:hover { border-color: #ddd; }
.slot-booked .booked-by { color: var(--orange-dark); font-weight: 600; }

.radio-row label { display: inline-flex; align-items: center; gap: 6px; margin: 6px 18px 6px 0; font-weight: normal; }

/* ---------- 纯 CSS 弹层 (无 JavaScript) ---------- */
.modal { display: none; position: fixed; inset: 0; background: rgba(0,0,0,.45); z-index: 100;
  align-items: center; justify-content: center; padding: 20px; }
.modal:target { display: flex; }
.modal-box { background: #fff; border-radius: var(--radius); max-width: 440px; width: 100%;
  padding: 24px; box-shadow: 0 8px 30px rgba(0,0,0,.25); border-top: 5px solid var(--orange); }
.modal-box h3 { margin-top: 0; }
.modal-actions { display: flex; gap: 12px; margin-top: 18px; flex-wrap: wrap; }

/* ---------- 后台导航 ---------- */
.admin-nav { background: var(--green); margin: 0; }
.admin-nav .wrap { display: flex; flex-wrap: wrap; gap: 4px; padding: 0 16px; }
.admin-nav a { color: #fff; text-decoration: none; padding: 12px 16px; font-size: 14px; display: block; }
.admin-nav a:hover, .admin-nav a.active { background: var(--green-dark); }
.admin-nav a.nav-right { margin-left: auto; }

.stat-cards { display: flex; gap: 14px; flex-wrap: wrap; margin: 16px 0; }
.stat-card { background: var(--green-light); border-left: 5px solid var(--orange);
  border-radius: 8px; padding: 14px 22px; min-width: 150px; }
.stat-card .num { font-size: 28px; font-weight: 700; color: var(--green); }
.stat-card .lbl { font-size: 13px; color: var(--muted); }

@media (max-width: 640px) {
  .site-title { font-size: 17px; }
  .site-subtitle { font-size: 13px; }
  .logo { height: 44px; }
  table.list { font-size: 13px; }
  table.list th, table.list td { padding: 6px; }
}