:root{
  --bg:#f5f7fb;
  --card:#ffffff;
  --line:#e4eaf5;
  --line2:#d0dae9;
  --text:#172033;
  --muted:#667085;
  --blue:#2563eb;
  --blue2:#1d4ed8;
  --sky:#0ea5e9;
  --green:#16a34a;
  --orange:#ea580c;
  --red:#e11d48;
  --amber:#f59e0b;
  --shadow:0 12px 30px rgba(30,50,90,.08);
  --radius:18px;
}
*{box-sizing:border-box;margin:0;padding:0;-webkit-tap-highlight-color:transparent}
body{
  min-height:100vh;
  background:var(--bg);
  color:var(--text);
  font-family:-apple-system,BlinkMacSystemFont,"Pretendard","Apple SD Gothic Neo","Microsoft YaHei",system-ui,sans-serif;
  -webkit-font-smoothing:antialiased;
}
button,input,textarea,select{font:inherit}
button{cursor:pointer;border:0}
input,textarea,select{
  width:100%;
  border:1px solid var(--line2);
  border-radius:12px;
  padding:12px 13px;
  background:#fbfdff;
  outline:none;
}
input:focus,textarea:focus,select:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(37,99,235,.12)}
.app-shell{min-height:100vh}
.topbar{
  position:sticky;top:0;z-index:20;
  height:62px;
  display:flex;align-items:center;gap:12px;
  padding:0 18px;
  background:rgba(255,255,255,.86);
  backdrop-filter:blur(14px) saturate(1.35);
  border-bottom:1px solid var(--line);
}
.logo{
  width:40px;height:40px;border-radius:14px;
  background:linear-gradient(135deg,var(--blue),var(--sky));
  color:#fff;display:grid;place-items:center;font-weight:900;
  box-shadow:0 8px 22px rgba(37,99,235,.25)
}
.brand{font-weight:900;letter-spacing:-.4px}
.brand small{display:block;color:var(--muted);font-size:11px;font-weight:700;margin-top:1px}
.spacer{flex:1}
.wrap{max-width:1060px;margin:0 auto;padding:20px 16px 56px}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.card{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  padding:20px;
}
.card + .card{margin-top:14px}
.hero{
  overflow:hidden;position:relative;
  background:linear-gradient(135deg,#edf4ff,#e5eeff 58%,#eefcff);
  border:1px solid #dbe7fb;
  border-radius:24px;
  box-shadow:var(--shadow);
  padding:28px 24px;
}
.hero:after{
  content:"";position:absolute;right:-50px;top:-60px;width:200px;height:200px;border-radius:50%;
  background:radial-gradient(circle,rgba(37,99,235,.18),rgba(14,165,233,.08),transparent 70%);
}
.eyebrow{font-size:12px;letter-spacing:3px;color:var(--blue);font-weight:900}
h1{font-size:28px;line-height:1.12;letter-spacing:-.9px;margin:7px 0}
h2{font-size:20px;letter-spacing:-.4px;margin-bottom:7px}
h3{font-size:16px;letter-spacing:-.3px}
p{color:var(--muted);line-height:1.55;font-size:14px}
.muted{color:var(--muted)}
.small{font-size:12px;color:var(--muted)}
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:44px;
  border-radius:13px;
  padding:0 16px;
  background:linear-gradient(135deg,var(--blue),var(--sky));
  color:#fff;
  font-weight:900;
  box-shadow:0 8px 20px rgba(37,99,235,.24);
}
.btn.full{width:100%;margin-top:12px}
.btn.ghost{background:#edf4ff;color:var(--blue2);box-shadow:none;border:1px solid #d9e5fb}
.btn.gray{background:#f1f5f9;color:#334155;box-shadow:none;border:1px solid var(--line)}
.btn.danger{background:#fff1f2;color:#be123c;box-shadow:none;border:1px solid #fecdd3}
.btn.green{background:linear-gradient(135deg,#16a34a,#22c55e)}
.btn.orange{background:linear-gradient(135deg,#ea580c,#f97316)}
.btn:active{transform:translateY(1px)}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.row.tight{gap:6px}
.field{margin-top:12px}
.field label{display:block;margin-bottom:6px;font-size:13px;font-weight:850;color:#334155}
.tabs{
  display:flex;gap:8px;overflow:auto;padding:4px 0 10px;margin-top:12px;
}
.tab{
  white-space:nowrap;
  border:1px solid var(--line);
  background:#fff;
  color:#475569;
  border-radius:999px;
  padding:10px 14px;
  font-weight:850;
}
.tab.on{background:var(--blue);color:#fff;border-color:var(--blue)}
.course-card{
  padding:18px;border:1px solid var(--line);border-radius:18px;background:#fff;
  display:flex;align-items:flex-start;gap:14px;justify-content:space-between;
  transition:.15s transform,.15s border-color;
}
.course-card:hover{transform:translateY(-2px);border-color:#9fc0ff}
.course-title{font-weight:900;font-size:16px}
.badge{
  display:inline-flex;align-items:center;gap:4px;
  border-radius:999px;padding:4px 10px;
  font-size:12px;font-weight:900;
  background:#eef4ff;color:var(--blue2);
}
.badge.green{background:#dcfce7;color:#15803d}
.badge.red{background:#ffe4e6;color:#be123c}
.badge.orange{background:#ffedd5;color:#c2410c}
.badge.gray{background:#f1f5f9;color:#475569}
.stat{
  background:#fff;border:1px solid var(--line);border-radius:16px;padding:15px;text-align:center
}
.stat .n{font-size:26px;font-weight:950}
.stat .t{font-size:12px;color:var(--muted);font-weight:800;margin-top:2px}
.codebox{
  border:1px solid #d8e5fb;
  border-radius:20px;
  background:linear-gradient(135deg,#eff6ff,#e9f2ff);
  text-align:center;
  padding:22px;
}
.bigcode{
  font-size:52px;
  letter-spacing:10px;
  font-weight:950;
  color:var(--blue2);
  font-variant-numeric:tabular-nums;
  margin:5px 0;
}
.progress{
  height:7px;background:#d7e5fb;border-radius:99px;overflow:hidden;margin:12px auto 3px;max-width:300px
}
.progress i{display:block;height:100%;width:50%;background:linear-gradient(90deg,var(--sky),var(--blue));border-radius:99px}
.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:16px;background:#fff}
table{width:100%;border-collapse:collapse;font-size:13px}
th,td{padding:11px;border-bottom:1px solid var(--line);text-align:left;white-space:nowrap}
th{font-size:12px;color:var(--muted);background:#f8fafc}
tr:last-child td{border-bottom:0}
.seat-stage{
  overflow:auto;
  background:linear-gradient(180deg,#eef4fc,#f8fbff);
  border:1px solid var(--line);
  border-radius:18px;
  padding:18px 12px;
}
.board{
  max-width:360px;margin:0 auto 18px;text-align:center;
  padding:10px;border-radius:28px 28px 8px 8px;
  background:#dce8fb;color:var(--blue2);
  font-size:12px;font-weight:950;letter-spacing:8px;
}
.seat-grid{display:inline-flex;flex-direction:column;gap:8px;min-width:100%}
.seat-row{display:flex;justify-content:center;gap:8px}
.seat{
  width:42px;height:38px;border-radius:10px 10px 5px 5px;
  display:grid;place-items:center;
  font-size:11px;font-weight:900;
  border:1px solid #93c5fd;
  background:#dbeafe;color:#1e40af;
}
.seat.mine{background:linear-gradient(135deg,#22c55e,#16a34a);color:#fff;border-color:#4ade80}
.seat.taken{background:#cbd5e8;color:#64748b;border-color:#b5c1d6}
.seat.block{background:#f8fafc;color:#cbd5e1;border-style:dashed}
.notice{
  border:1px solid var(--line);border-radius:16px;padding:15px;background:#fff;margin-top:10px
}
.notice .title{font-weight:950}
.notice .meta{font-size:12px;color:var(--muted);margin:4px 0 8px}
.qa-item{
  border:1px solid var(--line);border-radius:16px;padding:15px;background:#fff;margin-top:10px
}
.toast{
  position:fixed;left:50%;bottom:24px;transform:translateX(-50%);
  z-index:100;background:#111827;color:#fff;border-radius:999px;
  padding:12px 18px;font-weight:850;box-shadow:0 15px 30px rgba(0,0,0,.18)
}
.modal-backdrop{
  position:fixed;inset:0;background:rgba(15,23,42,.48);
  display:grid;place-items:center;padding:18px;z-index:50
}
.modal{
  width:min(460px,100%);
  background:#fff;border-radius:22px;padding:22px;
  box-shadow:0 25px 70px rgba(15,23,42,.25)
}
.divider{height:1px;background:var(--line);margin:14px 0}
.kv{display:flex;justify-content:space-between;gap:16px;margin-top:8px;font-size:14px}
.kv b{font-weight:950}
.warn{
  background:#fff7ed;border:1px solid #fed7aa;color:#9a3412;
  border-radius:14px;padding:12px;font-size:13px;line-height:1.55
}
@media(max-width:720px){
  .grid2,.grid3{grid-template-columns:1fr}
  .topbar{padding:0 14px}
  .wrap{padding:16px 12px 44px}
  h1{font-size:24px}
  .bigcode{font-size:42px;letter-spacing:7px}
  .course-card{flex-direction:column}
}