/* ============================================================
 * 中文学习系统 · 后台设计系统 admin.css
 * 主色调 #3b5bdb，Token 化，禁止硬编码颜色
 * ============================================================ */
:root {
  --primary: #3b5bdb;
  --primary-dark: #2f4bc0;
  --primary-light: #edf2ff;
  --danger: #e03131;
  --success: #2f9e44;
  --warning: #f08c00;
  --text: #1f2937;
  --text-sub: #6b7280;
  --bg: #f5f6fa;
  --card: #ffffff;
  --border: #e5e7eb;
  --radius: 8px;
  --gap: 12px;
  --sidebar-w: 220px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--text); font-size: 14px; line-height: 1.5;
}
a { color: var(--primary); text-decoration: none; }
hr { border: none; border-top: 1px solid var(--border); margin: 16px 0; }

/* ---------- 布局：侧边栏 + 主区 ---------- */
.layout { display: flex; min-height: 100vh; }
.sidebar {
  width: var(--sidebar-w); flex: none; color: #cdd6f4;
  background: linear-gradient(180deg, #2b3a8f 0%, #1f2a63 100%);
  display: flex; flex-direction: column; position: sticky; top: 0; height: 100vh; overflow-y: auto;
}
.sidebar .logo {
  padding: 20px 18px; font-size: 16px; font-weight: 700; color: #fff;
  display: flex; align-items: center; gap: 8px; border-bottom: 1px solid rgba(255,255,255,.1);
}
.sidebar nav { padding: 10px 0; flex: 1; }
.sidebar nav a {
  display: flex; align-items: center; gap: 10px; padding: 11px 18px;
  color: #cdd6f4; font-size: 14px; position: relative; transition: background .15s;
}
.sidebar nav a i { font-size: 18px; }
.sidebar nav a:hover { background: rgba(255,255,255,.06); color: #fff; }
.sidebar nav a.active { background: rgba(255,255,255,.12); color: #fff; font-weight: 600; }
.sidebar nav a.active::before {
  content: ""; position: absolute; left: 0; top: 8px; bottom: 8px; width: 3px;
  background: #fff; border-radius: 0 3px 3px 0; box-shadow: 0 0 8px rgba(255,255,255,.6);
}
.sidebar .foot { padding: 14px 18px; font-size: 12px; color: #93a0d6; border-top: 1px solid rgba(255,255,255,.1); }

.main { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.topbar {
  height: 56px; background: var(--card); border-bottom: 1px solid var(--border);
  display: flex; align-items: center; justify-content: space-between; padding: 0 20px; position: sticky; top: 0; z-index: 20;
}
.topbar .title { font-size: 16px; font-weight: 600; }
.topbar .actions { display: flex; align-items: center; gap: 12px; }
.content { padding: 20px; flex: 1; }

/* ---------- 卡片 ---------- */
.card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; margin-bottom: var(--gap); }
.card > h3 { font-size: 15px; margin-bottom: 14px; }
.grid { display: grid; gap: var(--gap); }
.grid.cols-4 { grid-template-columns: repeat(4, 1fr); }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 900px) { .grid.cols-4, .grid.cols-3 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .grid.cols-4, .grid.cols-3, .grid.cols-2 { grid-template-columns: 1fr; } .sidebar { position: fixed; z-index: 50; transform: translateX(-100%); } .sidebar.open { transform: none; } }

/* ---------- 统计卡 ---------- */
.stat { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; }
.stat .label { color: var(--text-sub); font-size: 13px; }
.stat .num { font-size: 28px; font-weight: 700; margin-top: 6px; color: var(--primary); }

/* ---------- 表单 ---------- */
.field { margin-bottom: 14px; }
.field > label { display: block; margin-bottom: 6px; color: var(--text-sub); font-size: 13px; }
/* 兜底：field 内所有输入控件继承 .input */
.input, .field input, .field select, .field textarea {
  width: 100%; height: 38px; padding: 0 12px; border: 1px solid var(--border);
  border-radius: var(--radius); font-size: 14px; color: var(--text); background: #fff; outline: none; transition: border-color .15s, box-shadow .15s;
}
.field textarea { height: auto; min-height: 80px; padding: 8px 12px; resize: vertical; }
.input:focus, .field input:focus, .field select:focus, .field textarea:focus {
  border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-light);
}
.field select {
  appearance: none; -webkit-appearance: none;
  background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='3'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 12px center; padding-right: 32px;
}
input[type=number]::-webkit-outer-spin-button, input[type=number]::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
input[type=number] { -moz-appearance: textfield; }
.form-row { display: flex; gap: var(--gap); }
.form-row .field { flex: 1; }

/* ---------- 开关 42x24 ---------- */
.switch { position: relative; display: inline-block; width: 42px; height: 24px; flex: none; }
.switch input { display: none; }
.switch .slider {
  position: absolute; inset: 0; background: #cbd5e1; border-radius: 24px; cursor: pointer; transition: background .2s;
}
.switch .slider::before {
  content: ""; position: absolute; width: 18px; height: 18px; left: 3px; top: 3px; background: #fff; border-radius: 50%; transition: transform .2s;
}
.switch input:checked + .slider { background: var(--primary); }
.switch input:checked + .slider::before { transform: translateX(18px); }
.switch:active .slider::before { width: 22px; }

/* ---------- 按钮 ---------- */
.btn {
  height: 38px; padding: 0 16px; border: 1px solid transparent; border-radius: var(--radius);
  font-size: 14px; cursor: pointer; display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  transition: transform .08s, background .15s, box-shadow .15s; white-space: nowrap; background: #fff;
}
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .6; cursor: not-allowed; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-ghost { border-color: var(--border); color: var(--text); background: #fff; }
.btn-ghost:hover { border-color: var(--primary); color: var(--primary); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { filter: brightness(.92); }
.btn-text { background: transparent; color: var(--primary); padding: 0 8px; }
.btn-sm { height: 30px; padding: 0 10px; font-size: 13px; }
.btn-block { width: 100%; }

/* ---------- 表格 ---------- */
.table-wrap { border: 1px solid var(--border); border-radius: var(--radius); overflow-x: auto; background: #fff; }
table.data { width: 100%; border-collapse: collapse; font-size: 14px; }
table.data th, table.data td { padding: 11px 14px; text-align: left; border-bottom: 1px solid var(--border); }
table.data th { background: #fafbfc; color: var(--text-sub); font-weight: 600; white-space: nowrap; }
table.data tbody tr:hover { background: var(--primary-light); }
table.data tbody tr:last-child td { border-bottom: none; }
table.data td input[type=checkbox] { accent-color: var(--primary); width: 16px; height: 16px; }
/* 操作列防挤压 */
table.data td.ops { white-space: nowrap; }
table.data td.ops .btn { flex: none; margin-right: 6px; }
.col-ops-1 { width: 80px; } .col-ops-2 { width: 140px; } .col-ops-4 { width: 300px; }

/* ---------- 标签 / 徽章 ---------- */
.tag { display: inline-block; padding: 2px 8px; border-radius: 10px; font-size: 12px; line-height: 18px; }
.tag-ok { background: #ebfbee; color: var(--success); }
.tag-no { background: #fff5f5; color: var(--danger); }
.tag-warn { background: #fff9db; color: var(--warning); }
.tag-info { background: var(--primary-light); color: var(--primary); }

/* ---------- 工具条 ---------- */
.toolbar { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; flex-wrap: wrap; }
.toolbar .spacer { flex: 1; }
.toolbar .input, .toolbar select { width: auto; min-width: 160px; }

/* ---------- 分页 ---------- */
.pager { display: flex; gap: 6px; justify-content: flex-end; margin-top: 14px; }
.pager a, .pager span { padding: 6px 12px; border: 1px solid var(--border); border-radius: 6px; background: #fff; color: var(--text); }
.pager .cur { background: var(--primary); color: #fff; border-color: var(--primary); }

/* ---------- 弹窗 ---------- */
.modal-mask { position: fixed; inset: 0; background: rgba(0,0,0,.45); display: none; align-items: center; justify-content: center; z-index: 100; padding: 16px; }
.modal-mask.show { display: flex; }
.modal { background: #fff; border-radius: var(--radius); width: 100%; max-width: 560px; max-height: 90vh; overflow-y: auto; }
.modal .modal-head { padding: 16px 18px; border-bottom: 1px solid var(--border); font-weight: 600; display: flex; justify-content: space-between; align-items: center; }
.modal .modal-body { padding: 18px; }
.modal .modal-foot { padding: 14px 18px; border-top: 1px solid var(--border); display: flex; justify-content: flex-end; gap: 10px; }
.modal .close-x { cursor: pointer; color: var(--text-sub); font-size: 20px; line-height: 1; }

/* ---------- Toast ---------- */
#toast { position: fixed; top: 20px; left: 50%; transform: translateX(-50%); z-index: 999; display: flex; flex-direction: column; gap: 8px; align-items: center; }
.toast-item { padding: 10px 18px; border-radius: var(--radius); color: #fff; font-size: 14px; box-shadow: 0 4px 12px rgba(0,0,0,.15); display: flex; align-items: center; gap: 8px; }
.toast-item.ok { background: var(--success); }
.toast-item.err { background: var(--danger); }
.toast-item.info { background: var(--primary); }

/* ---------- 登录 / 安装页 ---------- */
.login-body, .install-body {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, #3b5bdb 0%, #1f2a63 100%); padding: 16px;
}
.login-box, .install-box { background: #fff; border-radius: 12px; padding: 32px; width: 100%; max-width: 380px; }
.install-box { max-width: 460px; }
.login-box h1, .install-box h1 { font-size: 20px; text-align: center; margin-bottom: 24px; color: var(--text); }
.login-logo { text-align: center; margin-bottom: 8px; }
.login-logo i { font-size: 42px; color: var(--primary); }
.captcha-row { display: flex; gap: 10px; }
.captcha-row .input { flex: 1; }
.captcha-img { height: 38px; width: 110px; border: 1px solid var(--border); border-radius: var(--radius); cursor: pointer; }
.install-msg { padding: 12px; border-radius: var(--radius); margin-bottom: 16px; font-size: 14px; }
.install-msg.ok { background: #ebfbee; color: var(--success); }
.install-msg.err { background: #fff5f5; color: var(--danger); }
.lang-switch-mini { text-align: center; margin-top: 16px; font-size: 13px; }