/* ==========================================================
   网络搭建与基础运维 · 期中考试题库网站
   浅色主题 / 教材蓝 / 适配手机与打印
   ========================================================== */
:root {
  --blue: #1557b0;
  --blue-dark: #0d3f86;
  --blue-light: #e8f1fd;
  --blue-soft: #f2f7fe;
  --ink: #1b2431;
  --ink-2: #46536a;
  --ink-3: #7a879c;
  --line: #dfe7f2;
  --bg: #f4f7fc;
  --card: #ffffff;
  --ok: #14804a;
  --ok-bg: #eaf7f0;
  --bad: #c2352b;
  --bad-bg: #fdf0ef;
  --warn: #a76100;
  --warn-bg: #fff6e6;
  --shadow: 0 2px 10px rgba(22, 54, 105, .07);
  --shadow-lg: 0 10px 30px rgba(22, 54, 105, .12);
  --radius: 12px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", sans-serif;
  font-size: 15px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
.wrap { max-width: 1120px; margin: 0 auto; padding: 0 20px; }
button, input, textarea, select { font-family: inherit; font-size: inherit; }
button { cursor: pointer; }

/* ---------- header ---------- */
.topbar {
  background: linear-gradient(115deg, #0d3f86 0%, #1557b0 58%, #2f7ad6 100%);
  color: #fff;
  box-shadow: 0 2px 14px rgba(13, 63, 134, .22);
}
.topbar-inner { display: flex; align-items: center; justify-content: space-between; gap: 20px; flex-wrap: wrap; padding-top: 16px; padding-bottom: 12px; }
.brand { display: flex; align-items: center; gap: 14px; }
.brand-mark {
  width: 46px; height: 46px; flex: 0 0 46px; border-radius: 12px;
  background: rgba(255,255,255,.16); border: 1px solid rgba(255,255,255,.35);
  display: grid; place-items: center; font-size: 24px; font-weight: 700; letter-spacing: 1px;
}
.brand-text h1 { margin: 0; font-size: 19px; font-weight: 650; letter-spacing: .3px; }
.brand-text p { margin: 2px 0 0; font-size: 12.5px; opacity: .82; }
.tabs { display: flex; gap: 4px; flex-wrap: wrap; }
.tabs button {
  border: 1px solid transparent; background: transparent; color: rgba(255,255,255,.86);
  padding: 7px 15px; border-radius: 8px; font-size: 14px; transition: .18s;
}
.tabs button:hover { background: rgba(255,255,255,.13); }
.tabs button.active { background: #fff; color: var(--blue-dark); font-weight: 650; box-shadow: 0 2px 8px rgba(0,0,0,.12); }

/* ---------- generic ---------- */
main { min-height: 68vh; padding-top: 26px; padding-bottom: 50px; }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 22px; margin-bottom: 18px;
}
.card.tight { padding: 16px 18px; }
h2.section-title { font-size: 20px; margin: 0 0 4px; font-weight: 680; }
h3 { font-size: 16.5px; margin: 0 0 10px; font-weight: 650; }
.muted { color: var(--ink-3); font-size: 13px; }
.sub { color: var(--ink-2); font-size: 13.5px; }
.hero { background: linear-gradient(120deg, #ffffff 0%, #f0f6ff 100%); border-left: 4px solid var(--blue); }
.hero h2 { margin: 0 0 8px; font-size: 22px; }
.hero p { margin: 4px 0; color: var(--ink-2); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.spread { justify-content: space-between; }
.tag {
  display: inline-block; padding: 2px 9px; border-radius: 20px; font-size: 12px;
  background: var(--blue-light); color: var(--blue-dark); border: 1px solid #cfe1fa; white-space: nowrap;
}
.tag.gray { background: #f1f4f8; color: var(--ink-2); border-color: #e3e9f1; }
.tag.ok { background: var(--ok-bg); color: var(--ok); border-color: #bfe6cf; }
.tag.bad { background: var(--bad-bg); color: var(--bad); border-color: #f3cdca; }
.tag.warn { background: var(--warn-bg); color: var(--warn); border-color: #f4dfb5; }

.btn {
  border: 1px solid var(--line); background: #fff; color: var(--ink-2);
  padding: 8px 16px; border-radius: 8px; font-size: 14px; transition: .16s; white-space: nowrap;
}
.btn:hover { border-color: #a9c5ec; color: var(--blue); background: var(--blue-soft); }
.btn.primary { background: var(--blue); border-color: var(--blue); color: #fff; font-weight: 600; }
.btn.primary:hover { background: var(--blue-dark); border-color: var(--blue-dark); color: #fff; }
.btn.ghost { background: transparent; }
.btn.danger { color: var(--bad); border-color: #f0cdc9; }
.btn.danger:hover { background: var(--bad-bg); border-color: #e6b4af; }
.btn.sm { padding: 5px 11px; font-size: 12.5px; }
.btn:disabled { opacity: .5; cursor: not-allowed; }

/* ---------- home ---------- */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-bottom: 18px; }
.stat { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 15px 18px; box-shadow: var(--shadow); }
.stat .num { font-size: 26px; font-weight: 700; color: var(--blue); line-height: 1.25; }
.stat .lbl { color: var(--ink-3); font-size: 12.5px; }
.paper-card { position: relative; overflow: hidden; transition: .2s; }
.paper-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.paper-card .badge {
  position: absolute; right: -30px; top: 14px; transform: rotate(38deg);
  background: var(--blue); color: #fff; font-size: 11px; padding: 3px 38px; letter-spacing: 1px;
}
.paper-card .pname { font-size: 21px; font-weight: 700; color: var(--blue-dark); margin: 2px 0 2px; }
.paper-card .ptag { color: var(--ink-2); font-size: 13px; min-height: 42px; }
.paper-meta { display: flex; gap: 8px; flex-wrap: wrap; margin: 10px 0 14px; }
.progress { height: 7px; background: #edf2f9; border-radius: 8px; overflow: hidden; margin: 10px 0 14px; }
.progress > i { display: block; height: 100%; background: linear-gradient(90deg, #2f7ad6, #1557b0); border-radius: 8px; }
table.dist { width: 100%; border-collapse: collapse; font-size: 13.5px; }
table.dist th, table.dist td { border: 1px solid var(--line); padding: 7px 10px; text-align: center; }
table.dist th { background: var(--blue-soft); color: var(--blue-dark); font-weight: 600; }
table.dist td:first-child { text-align: left; }
.chapter-btn { display: flex; flex-direction: column; align-items: flex-start; gap: 4px; text-align: left; padding: 14px 16px; }
.chapter-btn strong { color: var(--blue-dark); font-size: 15px; }
.chapter-btn small { color: var(--ink-3); }

/* ---------- practice / exam layout ---------- */
.practice-layout { display: grid; grid-template-columns: 250px 1fr; gap: 18px; align-items: start; }
.sidebar { position: sticky; top: 16px; }
.qnav { display: grid; grid-template-columns: repeat(6, 1fr); gap: 6px; margin-top: 10px; }
.qnav button {
  border: 1px solid var(--line); background: #fff; color: var(--ink-2); border-radius: 6px;
  height: 32px; font-size: 12.5px; padding: 0; transition: .14s;
}
.qnav button:hover { border-color: var(--blue); }
.qnav button.cur { background: var(--blue); border-color: var(--blue); color: #fff; font-weight: 700; }
.qnav button.done-ok { background: var(--ok-bg); border-color: #bfe6cf; color: var(--ok); }
.qnav button.done-bad { background: var(--bad-bg); border-color: #f3cdca; color: var(--bad); }
.qnav button.done-neutral { background: #eef3fa; border-color: #cfdcee; color: var(--blue-dark); }
.legend { display: flex; gap: 12px; flex-wrap: wrap; font-size: 12px; color: var(--ink-3); margin-top: 12px; }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin-right: 4px; vertical-align: -1px; }
.exam-timer { font-variant-numeric: tabular-nums; font-weight: 700; color: var(--blue-dark); font-size: 18px; }
.exam-timer.urgent { color: var(--bad); }

.q-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 22px; margin-bottom: 16px; }
.q-head { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; margin-bottom: 12px; }
.q-no { font-weight: 700; color: var(--blue-dark); font-size: 15px; margin-right: 2px; }
.q-stem { font-size: 16px; line-height: 1.85; white-space: pre-line; margin: 4px 0 16px; }
.options { display: flex; flex-direction: column; gap: 9px; }
.option {
  display: flex; align-items: flex-start; gap: 10px; padding: 10px 13px; border: 1px solid var(--line);
  border-radius: 9px; cursor: pointer; transition: .15s; background: #fff; line-height: 1.65;
}
.option:hover { border-color: #a9c5ec; background: var(--blue-soft); }
.option input { margin-top: 5px; accent-color: var(--blue); flex: 0 0 auto; }
.option .opt-key { font-weight: 700; color: var(--blue-dark); }
.option.selected { border-color: var(--blue); background: var(--blue-light); }
.option.correct { border-color: #8fd0ac; background: var(--ok-bg); }
.option.wrong { border-color: #eeb3ae; background: var(--bad-bg); }
.fill-input, .essay-input {
  width: 100%; border: 1px solid var(--line); border-radius: 9px; padding: 10px 13px;
  background: #fff; color: var(--ink); outline: none; transition: .15s;
}
.fill-input:focus, .essay-input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(21,87,176,.1); }
.essay-input { min-height: 118px; resize: vertical; line-height: 1.7; }
.hint-line { font-size: 12.5px; color: var(--ink-3); margin: 8px 0 0; }
.q-actions { display: flex; gap: 9px; flex-wrap: wrap; margin-top: 18px; align-items: center; }
.feedback { margin-top: 16px; border-radius: 10px; padding: 14px 16px; border: 1px solid; font-size: 14px; }
.feedback.ok { background: var(--ok-bg); border-color: #bfe6cf; }
.feedback.bad { background: var(--bad-bg); border-color: #f3cdca; }
.feedback.neutral { background: var(--blue-soft); border-color: #cfe1fa; }
.feedback h4 { margin: 0 0 6px; font-size: 14.5px; }
.feedback p { margin: 6px 0 0; white-space: pre-line; line-height: 1.8; }
.feedback .label { font-weight: 700; color: var(--blue-dark); }
.feedback.ok .label { color: var(--ok); }
.feedback.bad .label { color: var(--bad); }
.self-rate { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 12px; align-items: center; }
.self-rate .btn.on { background: var(--blue); color: #fff; border-color: var(--blue); }
.src-note { font-size: 12px; color: var(--ink-3); margin-top: 12px; border-top: 1px dashed var(--line); padding-top: 9px; }

/* ---------- result / teacher ---------- */
.score-hero { display: flex; align-items: center; gap: 26px; flex-wrap: wrap; }
.score-circle {
  width: 120px; height: 120px; flex: 0 0 120px; border-radius: 50%;
  background: conic-gradient(var(--blue) calc(var(--pct) * 1%), #e8eef7 0);
  display: grid; place-items: center;
}
.score-circle > div { width: 96px; height: 96px; border-radius: 50%; background: #fff; display: grid; place-items: center; text-align: center; }
.score-circle b { font-size: 30px; color: var(--blue-dark); line-height: 1.1; }
.score-circle span { font-size: 11px; color: var(--ink-3); }
.result-item { border-left: 3px solid var(--line); padding: 10px 14px; margin-bottom: 10px; background: #fbfcfe; border-radius: 0 8px 8px 0; }
.result-item.bad { border-left-color: var(--bad); }
.result-item.ok { border-left-color: var(--ok); }
.print-head { display: none; }
.teacher-q { border: 1px solid var(--line); border-radius: 10px; padding: 16px 18px; margin-bottom: 12px; background: #fff; break-inside: avoid; }
.teacher-q .answer-block { background: var(--blue-soft); border: 1px solid #cfe1fa; border-radius: 8px; padding: 10px 13px; margin-top: 10px; font-size: 13.5px; white-space: pre-line; }
.sec-head { margin: 26px 0 12px; padding-bottom: 8px; border-bottom: 2px solid var(--blue); }
.sec-head span { color: var(--ink-3); font-size: 13px; font-weight: 400; margin-left: 10px; }
.empty { text-align: center; padding: 40px 20px; color: var(--ink-3); }
.empty .big { font-size: 40px; display: block; margin-bottom: 8px; }
.toast {
  position: fixed; right: 24px; bottom: 24px; z-index: 99; background: #1b2431; color: #fff;
  padding: 11px 18px; border-radius: 9px; font-size: 14px; box-shadow: var(--shadow-lg);
  opacity: 0; pointer-events: none; transition: .25s; max-width: 340px;
}
.toast.show { opacity: 1; transform: translateY(-4px); }
.footer { border-top: 1px solid var(--line); padding: 18px 0 26px; color: var(--ink-3); font-size: 12.5px; }
.footer .wrap { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .grid-3, .grid-4, .stats { grid-template-columns: repeat(2, 1fr); }
  .practice-layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
  .qnav { grid-template-columns: repeat(9, 1fr); }
}
@media (max-width: 600px) {
  .wrap { padding: 0 13px; }
  .brand-text h1 { font-size: 16px; }
  .brand-text p { font-size: 11.5px; }
  .tabs { width: 100%; }
  .tabs button { flex: 1; padding: 6px 4px; font-size: 12.5px; }
  .grid-3, .grid-4, .grid-2, .stats { grid-template-columns: 1fr; }
  .q-card, .card { padding: 16px; }
  .q-stem { font-size: 15px; }
  .qnav { grid-template-columns: repeat(8, 1fr); }
}

/* ---------- 登录 / 表单 ---------- */
.login-page { min-height: 78vh; display: flex; align-items: center; justify-content: center; padding: 34px 0; }
.login-card { width: 430px; max-width: 100%; background: #fff; border: 1px solid var(--line); border-radius: 16px; box-shadow: var(--shadow-lg); padding: 30px 30px 26px; }
.login-head { text-align: center; margin-bottom: 20px; }
.login-head .mark { width: 56px; height: 56px; margin: 0 auto 10px; border-radius: 15px; background: linear-gradient(135deg,#1557b0,#2f7ad6); color: #fff; display: grid; place-items: center; font-size: 27px; font-weight: 700; }
.login-head h2 { margin: 0; font-size: 20px; color: var(--blue-dark); }
.login-head p { margin: 4px 0 0; color: var(--ink-3); font-size: 13px; }
.login-tabs { display: flex; background: #f1f5fb; border-radius: 9px; padding: 4px; margin-bottom: 20px; }
.login-tabs button { flex: 1; border: 0; background: transparent; padding: 9px 0; border-radius: 7px; color: var(--ink-2); font-size: 14px; }
.login-tabs button.on { background: #fff; color: var(--blue-dark); font-weight: 650; box-shadow: var(--shadow); }
.field { margin-bottom: 15px; }
.field label { display: block; font-size: 13px; color: var(--ink-2); margin-bottom: 6px; font-weight: 600; }
.form-input { width: 100%; border: 1px solid var(--line); border-radius: 9px; padding: 10px 12px; background: #fff; color: var(--ink); outline: none; transition: .15s; }
.form-input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(21,87,176,.1); }
textarea.form-input { min-height: 100px; resize: vertical; line-height: 1.7; }
.login-hint { background: var(--blue-soft); border: 1px solid #d7e6fa; border-radius: 9px; padding: 10px 12px; font-size: 12.5px; color: var(--ink-2); margin-top: 16px; }
.login-alert { background: var(--warn-bg); border: 1px solid #f4dfb5; color: var(--warn); border-radius: 9px; padding: 10px 12px; font-size: 13px; margin-bottom: 14px; }
.error-page { text-align: center; padding: 60px 20px; color: var(--ink-2); }
.error-page .big { font-size: 44px; display: block; margin-bottom: 10px; }

/* ---------- 管理端 ---------- */
.table-scroll { overflow-x: auto; }
.admin-table { width: 100%; border-collapse: collapse; font-size: 13px; min-width: 640px; }
.admin-table th { background: var(--blue-soft); color: var(--blue-dark); font-weight: 600; }
.admin-table th, .admin-table td { border: 1px solid var(--line); padding: 8px 10px; text-align: center; white-space: nowrap; }
.admin-table td:first-child, .admin-table th:first-child { text-align: left; }
.admin-table tbody tr:hover td { background: #f8fbff; }
.import-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.import-input { min-height: 176px; font-family: ui-monospace, Consolas, "Microsoft YaHei", monospace; font-size: 13px; }
.mini-stats { display: grid; grid-template-columns: repeat(4,1fr); gap: 12px; margin-bottom: 16px; }
.mini-stat { background: var(--blue-soft); border: 1px solid #dce9fa; border-radius: 10px; padding: 12px 14px; }
.mini-stat b { display: block; font-size: 22px; color: var(--blue-dark); line-height: 1.3; }
.mini-stat span { font-size: 12px; color: var(--ink-3); }
.result-note { background: var(--ok-bg); border: 1px solid #bfe6cf; border-radius: 9px; padding: 11px 13px; font-size: 13px; margin-top: 12px; }
.result-note.bad { background: var(--bad-bg); border-color: #f3cdca; }
.form-row { display: flex; gap: 12px; flex-wrap: wrap; align-items: flex-end; }
.form-row .field { margin-bottom: 0; flex: 1; min-width: 160px; }
.who { display: flex; align-items: center; gap: 8px; font-size: 13px; color: rgba(255,255,255,.92); }
.who b { font-weight: 650; }
.pill { display: inline-block; padding: 1px 8px; border-radius: 12px; font-size: 11.5px; background: var(--blue-light); color: var(--blue-dark); }
.pill.off { background: #f1f4f8; color: var(--ink-3); }
.pill.ok { background: var(--ok-bg); color: var(--ok); }
.loading { text-align: center; padding: 50px 20px; color: var(--ink-3); }
@media (max-width: 760px) {
  .import-grid { grid-template-columns: 1fr; }
  .mini-stats { grid-template-columns: repeat(2,1fr); }
  .login-card { padding: 22px 18px; }
}

/* ---------- print ---------- */
@media print {
  body { background: #fff; font-size: 12px; line-height: 1.6; }
  .no-print, .tabs, .footer, .q-actions, .btn, .toast { display: none !important; }
  .wrap { max-width: 100%; padding: 0; }
  main { padding: 0; }
  .topbar { background: #fff; color: #000; box-shadow: none; border-bottom: 2px solid #333; }
  .topbar-inner { padding: 0 0 10px; }
  .brand-mark { background: #eee; color: #000; border: 1px solid #999; }
  .brand-text h1 { color: #000; }
  .brand-text p { color: #444; }
  .card, .q-card, .teacher-q { box-shadow: none; border: 1px solid #ddd; padding: 10px 12px; margin-bottom: 10px; }
  .teacher-q { break-inside: avoid; page-break-inside: avoid; }
  .sec-head { margin: 16px 0 8px; }
  .print-head { display: block; }
  .answer-block { background: #f5f5f5 !important; border: 1px solid #ccc !important; }
  .hero { background: #fff; }
  a { color: #000; text-decoration: none; }
}