:root {
  --blue: #0066d9;
  --blue-dark: #0050a8;
  --ink: #1f2329;
  --muted: #8a9099;
  --line: #e3e8ef;
  --bg: #f5f7fa;
  --card: #ffffff;
  --ok: #1a9d54;
  --warn: #c8553d;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
  overflow-x: hidden; /* 防止个别长内容把页面撑出横向滚动 */
}

/* 顶部导航 */
.topbar {
  background: #fff;
  border-bottom: 1px solid var(--line);
  padding: 0 20px;
  display: flex;
  gap: 28px;
  align-items: center;
  height: 58px;
  position: sticky;
  top: 0;
  z-index: 10;
  overflow-x: auto; /* 窄屏时导航内部可滚动，页面不整体横移 */
  -webkit-overflow-scrolling: touch;
}
.topbar .brand {
  font-weight: 700;
  font-size: 18px;
  color: var(--blue);
  margin-right: 8px;
}
.topbar a {
  text-decoration: none;
  color: var(--muted);
  font-size: 15px;
  padding: 6px 0;
  border-bottom: 2px solid transparent;
}
.topbar a.active,
.topbar a:hover { color: var(--blue); border-bottom-color: var(--blue); }

/* 布局 */
/* 布局：页面主体容器。桌面端加宽以更好容纳表格；窄屏（手机）下 max-width 不生效，自动占满宽度，无需单独适配 */
.wrap { max-width: 1080px; margin: 28px auto; padding: 0 16px; }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 26px 28px;
  box-shadow: 0 1px 3px rgba(20, 40, 80, 0.04);
  margin-bottom: 22px;
}
h1 { font-size: 24px; margin: 0 0 4px; }
h2 { font-size: 19px; margin: 0 0 14px; display: flex; align-items: center; gap: 8px; }
.sub { color: var(--muted); font-size: 14px; margin: 0 0 18px; }
.qr-tip-blue { color: var(--blue); font-weight: 700; }

/* 表单分区 */
.section-title { display: flex; align-items: center; gap: 8px; font-size: 16px; font-weight: 600; margin: 18px 0 10px; }
.section-title .ic { font-size: 18px; }
.field { margin-bottom: 16px; }
.field > label { display: block; font-size: 15px; font-weight: 600; margin-bottom: 6px; }
.req::after { content: " *"; color: var(--warn); }
.hint { color: var(--muted); font-size: 13px; margin-top: 4px; }

input[type="text"], input[type="password"], select {
  width: 100%;
  padding: 11px 12px;
  font-size: 15px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: #fff;
  color: var(--ink);
  outline: none;
}
input:focus, select:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(0,102,217,0.12); }

.btn {
  display: inline-block;
  background: var(--blue);
  color: #fff;
  border: none;
  border-radius: 9px;
  padding: 12px 20px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
}
.btn:hover { background: var(--blue-dark); }
.btn.secondary { background: #eef2f7; color: var(--ink); }
.btn.secondary:hover { background: #e2e8f0; }
.btn.danger { background: #fff; color: var(--warn); border: 1px solid var(--warn); }
.btn:disabled { opacity: .55; cursor: not-allowed; }

/* 教材列表 */
.group-name { font-size: 14px; color: var(--muted); font-weight: 600; margin: 14px 0 6px; }
.group-chip {
  display: inline-block; margin: 14px 0 8px; padding: 5px 12px;
  background: linear-gradient(135deg, #e8f3ff, #d6e9ff);
  color: #0050a8; font-size: 13px; font-weight: 700; border-radius: 999px;
  border: 1px solid #bcdcff;
}
.book {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 14px; border: 1px solid var(--line); border-radius: 12px;
  margin-bottom: 10px; background: #fff; cursor: pointer;
  transition: background .15s, border-color .15s, box-shadow .15s;
}
.book:hover { border-color: #bcdcff; }
.book.selected {
  background: #e8f3ff; border-color: #9cc8ff;
  box-shadow: 0 0 0 3px rgba(0,102,217,0.10);
}
.book input { width: 20px; height: 20px; flex: 0 0 auto; accent-color: var(--blue); }
.book .name { flex: 1 1 auto; min-width: 0; font-size: 15px; overflow-wrap: anywhere; word-break: break-word; }
.book .price { flex: 0 0 auto; color: var(--blue); font-weight: 600; font-size: 15px; white-space: nowrap; text-align: right; }
.book .price s { color: var(--muted); font-weight: 400; margin-right: 6px; }

/* 表格 */
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { padding: 9px 10px; border-bottom: 1px solid var(--line); text-align: left; }
th { color: var(--muted); font-weight: 600; background: #fafbfc; }
tbody tr:hover { background: #fafbfc; }

/* 提示条 */
.note { padding: 12px 14px; border-radius: 10px; font-size: 14px; margin: 14px 0; }
.note.info { background: #eef5ff; color: #0a4a9c; }
.note.ok { background: #eafaf0; color: #12693a; }
.note.err { background: #fdecea; color: #a3331f; }

.total-bar {
  display: flex; justify-content: space-between; align-items: stretch;
  margin-top: 16px; padding: 14px 16px; background: #f2f8ff; border-radius: 10px; gap: 12px;
}
.total-bar .tb-item { display: flex; flex-direction: column; gap: 2px; }
.total-bar .tb-label { font-size: 13px; color: var(--muted); }
.total-bar .amt { font-size: 22px; font-weight: 700; color: var(--blue); }
.total-bar .amt-sm { font-size: 18px; font-weight: 700; color: var(--blue); }

/* 提交成功页：清单与二维码 */
.done-books { list-style: none; margin: 0; padding: 0; }
.done-books li { display: flex; justify-content: space-between; gap: 12px; padding: 9px 2px; border-bottom: 1px dashed var(--line); font-size: 15px; }
.done-books .db-name { flex: 1 1 auto; min-width: 0; overflow-wrap: anywhere; word-break: break-word; }
.done-books .db-price { flex: 0 0 auto; text-align: right; white-space: nowrap; }
.done-books .db-old { color: var(--muted); text-decoration: line-through; font-weight: 400; margin-right: 8px; }
.done-books .db-cur { color: var(--blue); font-weight: 700; }

.qr-row { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; margin: 8px 0; }
.qr-img { width: 200px; height: 200px; object-fit: contain; border: 1px solid var(--line); border-radius: 10px; background: #fff; }

.qr-box { text-align: center; margin: 16px 0; }
.qr-box img { width: 220px; height: 220px; object-fit: contain; border: 1px solid var(--line); border-radius: 10px; background: #fff; }
.hidden { display: none; }
.row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.row > * { flex: 1; min-width: 160px; }

/* 已选教材清单（购物车） */
.cart-box { margin-top: 16px; border: 1px dashed var(--blue); border-radius: 12px; padding: 14px 16px; background: #f7fbff; }
.cart-list { list-style: none; margin: 0; padding: 0; }
.cart-list li { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 7px 0; border-bottom: 1px solid var(--line); font-size: 15px; }
.cart-list li:last-child { border-bottom: none; }
.cart-list .c-name { flex: 1 1 auto; min-width: 0; overflow-wrap: anywhere; word-break: break-word; }
.cart-list .c-price { flex: 0 0 auto; text-align: right; white-space: nowrap; }
.cart-list .c-old { color: var(--muted); text-decoration: line-through; font-weight: 400; margin-right: 8px; }
.cart-list .c-cur { color: var(--blue); font-weight: 700; }
.cart-list .c-del {
  flex: 0 0 auto;
  width: 24px; height: 24px;
  margin-left: 8px;
  border: none;
  border-radius: 50%;
  background: #eef0f3;
  color: #98a0aa;
  font-size: 13px;
  line-height: 1;
  cursor: pointer;
  transition: background .15s, color .15s;
}
.cart-list .c-del:hover { background: #ffe7e7; color: #e23b3b; }

/* 窄屏：原价与折扣价分两行显示，避免长书名列被挤压换行过多 */
@media (max-width: 600px) {
  .book .price { display: flex; flex-direction: column; align-items: flex-end; gap: 2px; }
  .book .price s { margin-right: 0; }
  .cart-list .c-price { display: flex; flex-direction: column; align-items: flex-end; gap: 2px; }
  .cart-list .c-old { margin-right: 0; }
  .done-books .db-price { display: flex; flex-direction: column; align-items: flex-end; gap: 2px; }
  .done-books .db-old { margin-right: 0; }
}

/* 提交成功页：个人信息条 */
.info-box { background: #f2f8ff; border-radius: 10px; padding: 12px 16px; margin: 6px 0 4px; }
.info-row { display: flex; gap: 10px; font-size: 15px; padding: 3px 0; }
.info-lbl { color: var(--muted); min-width: 42px; }

/* 系统后台班级列表：防止页面横向溢出 */
.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.act-row { display: flex; flex-wrap: wrap; gap: 6px; }
.act-row .btn { flex: 0 0 auto; font-size: 13px; padding: 7px 10px; }

/* 班级管理：付款审核勾选框 + 已确认行浅绿底色 */
.paid-check { display: inline-flex; align-items: center; gap: 6px; cursor: pointer; font-size: 14px; color: var(--ok); white-space: nowrap; }
.paid-check input { width: 18px; height: 18px; flex: 0 0 auto; accent-color: var(--ok); cursor: pointer; }
tbody tr.paid-row td { background: #eafaf0; }
tbody tr.paid-row:hover td { background: #ddf4e6; }

/* 系统后台班级列表：分配列宽——「收款二维码」占约 33%，其余列相应收窄。
   仅在较宽屏幕启用固定布局，窄屏（手机）不启用，保持原有自适应。 */
@media (min-width: 720px) {
  .classes-table { table-layout: fixed; }
  .classes-table th:nth-child(1) { width: 6%; }   /* 年级 */
  .classes-table th:nth-child(2) { width: 14%; }  /* 班级 */
  .classes-table th:nth-child(3) { width: 10%; }  /* 已提交人数 */
  .classes-table th:nth-child(4) { width: 9%; }   /* 付款人数 */
  .classes-table th:nth-child(5) { width: 11%; }  /* 付款金额 */
  .classes-table th:nth-child(6) { width: 33%; }  /* 收款二维码 */
  .classes-table th:nth-child(7) { width: 17%; }  /* 操作 */
  .classes-table .qr-cell { vertical-align: top; }
  .classes-table .qrFile { width: 100%; max-width: 100%; box-sizing: border-box; }
}

/* 系统后台：操作手册视图 */
#guideView > .card > h2 { margin-top: 22px; }
#guideView > .card > h2:first-of-type { margin-top: 8px; }