/* 数学学习管理 App · 统一样式 */
* { box-sizing: border-box; }
:root {
  --blue: #0b3d91; --blue2: #1c5bc4; --ink: #1a2230; --sub: #64748b;
  --line: #e2e8f0; --bg: #f4f6f9; --ok: #0f8a4d; --warn: #c77700; --bad: #c1121f;
}
html, body { margin: 0; padding: 0; }
body { background: var(--bg); color: var(--ink); font-size: 16px; line-height: 1.6;
  font-family: -apple-system, "Microsoft YaHei", "PingFang SC", sans-serif; }

/* ---------- 顶栏 ---------- */
.topbar { position: sticky; top: 0; z-index: 50; display: flex; align-items: center; gap: 18px;
  padding: 10px 20px; background: var(--blue); color: #fff; flex-wrap: wrap;
  box-shadow: 0 2px 12px rgba(11,61,145,.28); }
.brand { display: flex; align-items: center; gap: 9px; font-weight: 800; font-size: 18px; }
.logo { display: inline-grid; place-items: center; width: 28px; height: 28px; border-radius: 8px;
  background: #fff; color: var(--blue); font-size: 16px; }
.nav { display: flex; gap: 4px; flex-wrap: wrap; }
.nav a { color: rgba(255,255,255,.82); text-decoration: none; padding: 6px 13px; border-radius: 8px;
  font-size: 15px; font-weight: 600; white-space: nowrap; }
.nav a:hover { background: rgba(255,255,255,.14); color: #fff; }
.nav a.on { background: #fff; color: var(--blue); }
.nav a.dim { opacity: .55; }
.nav a.dim i { font-style: normal; font-size: 11px; margin-left: 4px; padding: 1px 5px;
  border-radius: 8px; background: rgba(255,255,255,.25); }
.topright { margin-left: auto; display: flex; align-items: center; gap: 12px; font-size: 13.5px; }
.net { padding: 3px 10px; border-radius: 20px; background: rgba(255,255,255,.16); }
.net.bad { background: #c1121f; }

/* ---------- 布局 ---------- */
.view { padding: 20px 22px 90px; max-width: 1500px; }
.pagehead { display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap; margin-bottom: 4px; }
h1 { font-size: 25px; margin: 0; color: var(--blue); }
.lead { color: var(--sub); margin: 2px 0 16px; font-size: 14.5px; }
.loading { padding: 60px; text-align: center; color: var(--sub); }

/* ---------- 通用件 ---------- */
.card { background: #fff; border: 1px solid var(--line); border-radius: 12px;
  box-shadow: 0 2px 10px rgba(16,32,64,.06); }
.pad { padding: 16px 18px; }
.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.spread { justify-content: space-between; }
.grow { flex: 1; min-width: 0; }
.muted { color: var(--sub); font-size: 14px; }
.right { text-align: right; }

button, .btn { border: 0; border-radius: 8px; padding: 8px 16px; font-size: 15px; font-weight: 700;
  cursor: pointer; background: var(--blue); color: #fff; font-family: inherit; }
button:hover, .btn:hover { filter: brightness(1.08); }
button:disabled { opacity: .5; cursor: not-allowed; filter: none; }
.btn.ghost { background: #fff; color: var(--blue); border: 1px solid #c9d6ea; }
.btn.line { background: #fff; color: var(--blue); border: 1px solid var(--blue); }
.btn.ok { background: var(--ok); } .btn.warn { background: var(--warn); }
.btn.bad { background: var(--bad); } .btn.sm { padding: 5px 11px; font-size: 13.5px; }
.btn.dimbtn { background: #eef2f8; color: #475569; border: 1px solid #d7e0ec; }

input[type=text], input[type=password], input[type=number], select, textarea {
  border: 1px solid #cbd5e1; border-radius: 8px; padding: 8px 11px; font-size: 15px;
  font-family: inherit; background: #fff; color: var(--ink); }
textarea { font-family: "Cascadia Mono", Consolas, monospace; font-size: 14px; line-height: 1.75; }
input:focus, select:focus, textarea:focus { outline: 2px solid var(--blue); border-color: var(--blue); }
select { min-width: 130px; }

.pill { display: inline-block; font-size: 12.5px; font-weight: 700; border-radius: 20px;
  padding: 2px 11px; background: #e2e8f0; color: #475569; }
.pill.todo { background: #e2e8f0; color: #475569; }
.pill.draft { background: #fdeccd; color: #9a6200; }
.pill.confirmed { background: var(--ok); color: #fff; }
.pill.on { background: var(--blue); color: #fff; }
.pill.ai { background: #ede4ff; color: #5b21b6; }

table.grid { width: 100%; border-collapse: collapse; font-size: 14.5px; }
table.grid th, table.grid td { text-align: left; padding: 9px 10px; border-bottom: 1px solid var(--line); }
table.grid th { background: #f7f9fc; color: #475569; font-size: 13.5px; position: sticky; top: 64px; }
table.grid tr:hover td { background: #fafcff; }

.empty { padding: 44px; text-align: center; color: var(--sub); }
.toast { position: fixed; left: 50%; bottom: 34px; transform: translateX(-50%) translateY(20px);
  background: #0b1220; color: #fff; padding: 11px 22px; border-radius: 10px; font-size: 15px;
  opacity: 0; pointer-events: none; transition: all .22s; z-index: 999; max-width: 80vw; }
.toast.on { opacity: .96; transform: translateX(-50%) translateY(0); }
.toast.err { background: #8b1220; }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 14px; }
.stat { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; }
.stat .n { font-size: 32px; font-weight: 800; color: var(--blue); line-height: 1.15; }
.stat .t { color: var(--sub); font-size: 13.5px; margin-top: 2px; }

.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip { border: 1.5px solid #cbd5e1; background: #fff; color: #475569; border-radius: 16px;
  padding: 3px 12px; font-size: 13.5px; cursor: pointer; user-select: none; }
.chip.on { border-color: var(--blue); background: var(--blue); color: #fff; font-weight: 700; }

/* 校对：左图右编辑 */
.split { display: grid; grid-template-columns: minmax(0,1fr) minmax(0,1.06fr); align-items: start; }
@media (max-width: 720px) { .split { grid-template-columns: 1fr; } }
.split > .pic { padding: 12px; background: #fafbfd; border-right: 1px solid #eef2f7; position: relative; }
.split > .pic img { width: 100%; height: auto; max-height: 78vh; object-fit: contain;
  border: 1px solid var(--line); border-radius: 8px; background: #fff; display: block; margin: 0 auto;
  transition: transform .18s; }
.imgtools { position: absolute; top: 18px; right: 18px; z-index: 3; display: flex; gap: 5px; align-items: center;
  background: rgba(255,255,255,.9); border: 1px solid var(--line); border-radius: 9px; padding: 4px 6px;
  box-shadow: 0 2px 8px rgba(16,32,64,.12); }
.imgtools button { padding: 3px 9px; font-size: 13px; border-radius: 6px; font-weight: 700;
  background: #eef3fb; color: var(--blue); border: 1px solid #cdd9ea; cursor: pointer; }
.imgtools .deg { font-size: 12px; color: var(--sub); min-width: 34px; text-align: center; }
.split > .edit { padding: 12px 15px; min-width: 0; display: flex; flex-direction: column; gap: 9px; }

.preview { border: 1px dashed #cbd5e1; border-radius: 8px; padding: 11px 13px; background: #fcfdff;
  font-size: 15.5px; line-height: 2; white-space: pre-wrap; word-break: break-word;
  min-height: 60px; max-height: 420px; overflow: auto; }
.preview .katex { font-size: 1.05em; }
.srcbox { display: none; border: 1px solid var(--line); border-radius: 8px; padding: 10px 13px;
  background: #f8fafc; font-family: "Cascadia Mono", Consolas, monospace; font-size: 13px;
  color: #8a94a6; white-space: pre-wrap; word-break: break-word; max-height: 240px; overflow: auto; }
.srcbox.on { display: block; }
.sect { font-size: 12.5px; font-weight: 700; color: var(--sub); letter-spacing: 1px; }

/* 上传 */
.drop { border: 2.5px dashed #b9c9e0; border-radius: 14px; padding: 40px; text-align: center;
  background: #fbfdff; color: var(--sub); cursor: pointer; transition: all .18s; }
.drop.hot { border-color: var(--blue); background: #eef5ff; color: var(--blue); }
.drop b { color: var(--blue); font-size: 17px; }
.thumbs { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 12px; }
.thumb { border: 1px solid var(--line); border-radius: 10px; overflow: hidden; background: #fff; }
.thumb img { width: 100%; height: 130px; object-fit: cover; display: block; background: #f1f5fa; }
.thumb .cap { padding: 7px 9px; font-size: 12.5px; color: var(--sub); word-break: break-all; }

/* 结构维护 */
.tree { font-size: 15px; }
.tree .bk { margin: 6px 0 2px; font-weight: 800; color: var(--blue); font-size: 17px; }
.tree .un { margin: 10px 0 2px 16px; font-weight: 700; color: #24406e; }
.tree .sc { margin: 4px 0 4px 34px; }
.tree .sec-line { display: flex; align-items: center; gap: 8px; padding: 3px 0; }
.tree .kp { margin-left: 34px; padding: 5px 10px; border-left: 3px solid #dbe4f0; color: #33465f; font-size: 14px; }
.kp-item { display: flex; align-items: flex-start; gap: 8px; padding: 5px 0; }
.kp-item .txt { flex: 1; min-width: 0; }
.kp-item .tag { font-size: 11.5px; padding: 1px 7px; border-radius: 8px; }
.tag.重点★ { background: #fde2e2; color: #a11222; }
.tag.易错⚠ { background: #fff0d6; color: #8a5a00; }
.tiny { font-size: 12.5px; color: var(--sub); }
.backbar { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
a.link { color: var(--blue2); text-decoration: none; font-weight: 700; }
a.link:hover { text-decoration: underline; }
hr.sep { border: 0; border-top: 1px dashed var(--line); margin: 12px 0; }

/* ---------- 登录页 ---------- */
body.locked { overflow: hidden; }
.loginwrap { position: fixed; inset: 0; z-index: 900; display: none;
  align-items: center; justify-content: center; padding: 22px;
  background: linear-gradient(160deg, #08296b 0%, #0b3d91 34%, #1c5bc4 68%, #e8eefa 100%); }
.loginwrap.on { display: flex; }
.logincard { width: 100%; max-width: 400px; background: #fff; border-radius: 16px;
  padding: 32px 28px 26px; box-shadow: 0 20px 55px rgba(4,20,50,.42); }
.lglogo { width: 56px; height: 56px; border-radius: 16px; margin: 0 auto 15px;
  background: var(--blue); color: #fff; display: grid; place-items: center;
  font-size: 28px; font-weight: 800; box-shadow: 0 6px 18px rgba(11,61,145,.35); }
.lgtitle { text-align: center; font-size: 22px; font-weight: 800; color: var(--blue); letter-spacing: .5px; }
.lgsub { text-align: center; color: var(--sub); font-size: 14px; margin: 4px 0 22px; }
.lgfield { display: block; margin-bottom: 15px; }
.lgfield > span { display: block; font-size: 13.5px; font-weight: 700; color: #475569; margin-bottom: 6px; }
.lgfield input { width: 100%; padding: 12px 14px; font-size: 16px; border-radius: 9px;
  border: 1.5px solid #cbd5e1; background: #fafcff; }
.lgfield input:focus { background: #fff; }
.lgerr { color: var(--bad); font-size: 14px; font-weight: 600; text-align: center;
  min-height: 21px; margin: 2px 0 10px; }
.lgbtn { width: 100%; padding: 13px; font-size: 16.5px; font-weight: 800;
  border-radius: 10px; letter-spacing: 2px; }
@media (max-width: 430px) {
  .loginwrap { padding: 16px; }
  .logincard { padding: 26px 20px 22px; border-radius: 14px; }
  .lglogo { width: 50px; height: 50px; font-size: 25px; }
  .lgtitle { font-size: 20px; }
}

/* 顶栏用户区 */
#userBox { font-weight: 700; color: #fff; }
.logout { background: rgba(255,255,255,.16); color: #fff; border: 1px solid rgba(255,255,255,.38);
  padding: 3px 13px; font-size: 13px; font-weight: 700; border-radius: 16px; cursor: pointer; }
.logout:hover { background: rgba(255,255,255,.3); filter: none; }