*{box-sizing:border-box}
:root{
  --ink:#1f1a2e;
  --text:#645d73;
  --muted:#91899f;
  --line:rgba(55,43,78,.12);
  --line-strong:rgba(55,43,78,.18);
  --bg:#f7f4ff;
  --card:#fff;
  --purple:#7a55d7;
  --purple-soft:#f2eaff;
  --aqua:#eafcff;
  --mint:#ecfbef;
  --peach:#fff4ea;
  --pink:#ffeaf2;
  --blue:#edf4ff;
  --ok:#2d8a62;
  --warn:#9a5b00;
  --bad:#a33b3b;
  --shadow:0 26px 90px rgba(72,54,130,.13);
}
body{
  margin:0;
  font-family:"Microsoft YaHei","PingFang SC",Arial,sans-serif;
  color:var(--ink);
  background:
    radial-gradient(circle at 8% 9%,rgba(234,252,255,.9),transparent 32%),
    radial-gradient(circle at 88% 14%,rgba(242,234,255,.94),transparent 36%),
    radial-gradient(circle at 50% 100%,rgba(255,234,242,.72),transparent 40%),
    linear-gradient(145deg,#fff,#f7f4ff 54%,#edfaff);
  font-size:16px;
  line-height:1.55;
}
a{color:inherit;text-decoration:none}
.page{width:min(100%,1180px);margin:0 auto;padding:10px 24px 24px}
.topbar{
  min-height:68px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  margin-bottom:14px;
  padding:16px 20px 14px;
  border:1px solid rgba(31,26,46,.06);
  border-radius:34px;
  background:rgba(255,255,255,.72);
  backdrop-filter:blur(14px);
  box-shadow:var(--shadow);
}
.brand{display:flex;align-items:center;gap:10px}
.mark{
  width:32px;height:32px;border-radius:11px;
  display:grid;place-items:center;
  background:var(--purple-soft);
  color:var(--purple);
  font-weight:950;
  border:1px solid rgba(122,85,215,.18);
}
.brand b{display:block;font-size:16px}
.brand span{display:block;color:var(--muted);font-size:12px}
.nav{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}
.nav a,.btn{
  min-height:28px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:6px;
  padding:4px 10px;
  border:1px solid var(--line-strong);
  border-radius:999px;
  background:#fff;
  color:#665f74;
  font:inherit;
  font-size:11.5px;
  font-weight:700;
  cursor:pointer;
}
.nav a.active,.btn.primary{background:var(--purple);border-color:var(--purple);color:#fff}
.nav a:hover,.btn:hover{border-color:rgba(122,85,215,.28);box-shadow:0 8px 18px rgba(72,54,130,.08)}
.layout{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:16px;margin-top:16px;align-items:start}
.card{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:22px;
  padding:16px;
  box-shadow:var(--shadow);
}
.hero{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:16px;align-items:center}
.kicker{margin:0 0 4px;color:var(--purple);font-size:12px;font-weight:900;letter-spacing:.13em;text-transform:uppercase}
h1,h2,h3{margin:0;color:#071427;line-height:1.25}
h1{font-size:28px}
h2{font-size:19px}
h3{font-size:15px}
p{margin:8px 0 0;color:var(--text)}
.muted{color:var(--muted)}
.grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
.lesson-list,.submission-list,.feedback-list{display:grid;gap:10px}
.lesson-row,.submission-row,.feedback-row,.resource-row{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:10px;
  align-items:center;
  padding:12px;
  border:1px solid var(--line);
  border-radius:12px;
  background:#fbfdff;
}
.row-meta{display:flex;flex-wrap:wrap;gap:6px;margin-top:6px}
.tag{
  display:inline-flex;
  align-items:center;
  min-height:24px;
  padding:3px 9px;
  border:1px solid var(--line);
  border-radius:999px;
  background:#fff;
  color:#34495f;
  font-size:12px;
  font-weight:650;
}
.tag input{width:auto;margin-right:5px}
.tag.ok{color:var(--ok);border-color:#b8dacb;background:#eefaf4}
.tag.warn{color:var(--warn);border-color:#e9d2a8;background:#fff8e8}
.tag.bad{color:var(--bad);border-color:#efc4c4;background:#fff2f2}
.section{margin-top:14px}
.section-head{display:flex;align-items:flex-end;justify-content:space-between;gap:12px;margin-bottom:10px}
.form{display:grid;gap:12px}
.form-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
label{display:grid;gap:6px;font-weight:760;color:#1a2c41;font-size:13px}
input,select,textarea{
  width:100%;
  border:1px solid var(--line);
  border-radius:12px;
  padding:9px 11px;
  font:inherit;
  font-size:14px;
  line-height:1.45;
  color:var(--ink);
  background:#fff;
}
input:focus,select:focus,textarea:focus{outline:3px solid rgba(122,85,215,.18);border-color:rgba(122,85,215,.45)}
textarea{min-height:104px;resize:vertical}
.upload-box{
  border:1px dashed #abc0d8;
  border-radius:12px;
  padding:14px;
  background:#f8fbff;
}
.button-row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.side{display:grid;gap:14px;position:sticky;top:12px}
.mini-list{display:grid;gap:8px;margin-top:10px}
.mini-item{display:flex;justify-content:space-between;gap:10px;border-top:1px solid var(--line);padding-top:8px}
.table{width:100%;border-collapse:collapse}
.table th,.table td{border-bottom:1px solid var(--line);padding:10px 8px;text-align:left;vertical-align:top}
.table th{font-size:12px;color:var(--muted);font-weight:800}
.placeholder{
  padding:12px;
  border:1px solid var(--line);
  border-radius:14px;
  background:#fbfcff;
  color:var(--muted);
}
.status{
  padding:12px;
  border:1px solid var(--line);
  border-radius:12px;
  background:#f8fbff;
  color:#25384d;
  white-space:pre-wrap;
  font-size:15px;
  line-height:1.5;
}
.review-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-top:12px}
.info-tile{padding:12px;border:1px solid var(--line);border-radius:14px;background:#fbfcff}
.info-tile b{display:block;color:var(--ink);font-size:15px}
.info-tile span{display:block;margin-top:3px;color:var(--muted);font-size:12px}
.feedback-template{display:grid;gap:8px;margin-top:10px}
.template-btn{width:100%;justify-content:flex-start;border-radius:12px;background:#fbfcff;color:#334155}
.file-preview{display:grid;gap:8px}
.resource-row:hover{border-color:rgba(114,86,200,.32);background:#fff}
.lock-screen{
  position:fixed;inset:0;z-index:9999;
  display:flex;align-items:center;justify-content:center;
  padding:22px;
  background:
    radial-gradient(circle at 8% 9%,rgba(234,252,255,.9),transparent 32%),
    radial-gradient(circle at 88% 14%,rgba(242,234,255,.94),transparent 36%),
    radial-gradient(circle at 50% 100%,rgba(255,234,242,.72),transparent 40%),
    linear-gradient(145deg,#fff,#f7f4ff 54%,#edfaff);
}
.lock-card{
  width:min(100%,360px);
  padding:20px;
  border:1px solid var(--line);
  border-radius:24px;
  background:rgba(255,255,255,.94);
  box-shadow:var(--shadow);
  text-align:left;
}
.lock-card .mark{width:28px;height:28px;margin:0 0 12px;border-radius:10px;font-size:12px}
.lock-card h1{font-size:22px;letter-spacing:-.025em}
.lock-card p{font-size:12.5px;line-height:1.55}
.lock-card input{margin-top:12px;text-align:center}
.lock-actions{display:flex;justify-content:flex-end;margin-top:10px}
.lock-actions .btn{min-width:68px}
.lock-error{display:none;margin-top:8px;color:var(--bad);font-size:12px;font-weight:800}
@media(max-width:820px){
  .page{padding:12px}
  .topbar{align-items:flex-start;flex-direction:column}
  .nav{justify-content:flex-start;width:100%;overflow-x:auto;flex-wrap:nowrap;padding-bottom:2px}
  .layout,.hero,.grid,.form-grid,.review-grid{grid-template-columns:1fr}
  .side{position:static}
  h1{font-size:24px}
}