:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --ink: #1f2937;
  --muted: #6b7280;
  --brand: #4f46e5;
  --brand-ink: #ffffff;
  --err: #dc2626;
  --ok: #16a34a;
  --border: #e5e7eb;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: var(--bg);
  color: var(--ink);
}

.topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 20px;
  background: var(--card);
  border-bottom: 1px solid var(--border);
}

.brand { font-weight: 700; color: var(--brand); font-size: 1.1rem; }
.whoami { margin-left: auto; color: var(--muted); font-size: .9rem; }
.link-btn { background: none; border: none; color: var(--brand); cursor: pointer; font: inherit; }

#app {
  max-width: 560px;
  margin: 28px auto;
  padding: 0 16px;
  display: grid;
  gap: 18px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
  box-shadow: 0 1px 2px rgba(0,0,0,.04);
}

h2 { margin: 0 0 14px; font-size: 1.15rem; }
h3 { margin: 0 0 10px; }

.tabs { display: flex; gap: 6px; margin-bottom: 18px; }
.tab {
  flex: 1; padding: 9px; border: 1px solid var(--border); background: #fafafa;
  border-radius: 8px; cursor: pointer; font: inherit; color: var(--muted);
}
.tab.active { background: var(--brand); color: var(--brand-ink); border-color: var(--brand); }

.form { display: grid; gap: 14px; }
.form.row { grid-template-columns: 1fr auto; align-items: end; }
label { display: grid; gap: 6px; font-size: .9rem; color: var(--muted); }
input, textarea, select {
  font: inherit; padding: 10px; border: 1px solid var(--border); border-radius: 8px; width: 100%;
  color: var(--ink); background: #fff;
}
textarea { resize: vertical; font-family: ui-monospace, monospace; }
small { color: var(--muted); }

button[type="submit"], #kickedOk {
  background: var(--brand); color: var(--brand-ink); border: none; padding: 11px 16px;
  border-radius: 8px; cursor: pointer; font: inherit; font-weight: 600;
}
button[disabled] { opacity: .6; cursor: progress; }

.msg { margin: 4px 0 0; font-size: .88rem; min-height: 1.1em; }
.msg.error { color: var(--err); }
.msg.ok { color: var(--ok); }
.muted { color: var(--muted); }

.class-list { display: grid; gap: 10px; }
.class-row {
  display: flex; align-items: center; gap: 10px; padding: 10px 12px;
  border: 1px solid var(--border); border-radius: 8px; background: #fafafa;
}
.class-row .code {
  font-family: ui-monospace, monospace; font-weight: 700; letter-spacing: 1px;
  background: #eef2ff; color: var(--brand); padding: 2px 8px; border-radius: 6px;
}
.class-row .count { margin-left: auto; color: var(--muted); font-size: .85rem; }

.modal {
  position: fixed; inset: 0; background: rgba(0,0,0,.5);
  display: flex; align-items: center; justify-content: center; padding: 16px;
}
.modal-box { background: var(--card); border-radius: 12px; padding: 24px; max-width: 380px; text-align: center; }
.modal-box button { margin-top: 14px; }
[hidden] { display: none !important; }