:root {
  --bg: #f4f5f7; --card: #fff; --text: #1c1e21; --muted: #6b7280; --line: #e2e4e8;
  --accent: #2563eb; --late-bg: #fff1f2; --late-line: #fecdd3; --late-text: #b91c1c; --ok: #15803d; --radius: 10px;
}
* { box-sizing: border-box; }
body { margin: 0; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; background: var(--bg); color: var(--text); font-size: 16px; line-height: 1.4; }
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 8px; padding: 10px 16px; background: var(--card); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 1; }
.topbar h1 { font-size: 18px; margin: 0; }
main { max-width: 960px; margin: 0 auto; padding: 16px; }
h2 { font-size: 18px; margin: 0 0 12px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; margin-bottom: 16px; }
button { font: inherit; padding: 8px 14px; min-height: 44px; border-radius: 8px; border: 1px solid var(--line); background: #fff; color: var(--text); cursor: pointer; }
button.primary { background: var(--accent); color: #fff; border-color: var(--accent); }
button.danger { color: var(--late-text); }
button.small { min-height: 36px; padding: 4px 10px; font-size: 14px; }
button:disabled { opacity: .5; cursor: default; }
input, select { font: inherit; padding: 8px 10px; min-height: 44px; border: 1px solid var(--line); border-radius: 8px; width: 100%; background: #fff; }
label { display: block; font-size: 14px; color: var(--muted); margin-bottom: 4px; }
.field { margin-bottom: 14px; }
.row { display: flex; flex-wrap: wrap; gap: 8px; align-items: flex-end; }
.row .field { margin: 0; flex: 1 1 140px; }
.pills { display: flex; flex-wrap: wrap; gap: 8px; }
.pills button { min-width: 48px; }
.pills button.selected, .tabs button.selected { background: var(--accent); color: #fff; border-color: var(--accent); }
.error { color: var(--late-text); margin: 8px 0 0; min-height: 1.2em; font-size: 14px; }
.muted { color: var(--muted); font-size: 14px; }
.roster { list-style: none; margin: 0; padding: 0; }
.roster li { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 16px; margin-bottom: 8px; display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px; }
.roster li.late { background: var(--late-bg); border-color: var(--late-line); }
.roster .name { flex: 1 1 160px; font-weight: 600; }
.roster .status { flex: 1 1 160px; color: var(--ok); font-size: 15px; }
.roster li.late .status { color: var(--late-text); }
.roster .actions { display: flex; gap: 8px; }
.roster form { flex-basis: 100%; display: flex; flex-wrap: wrap; gap: 8px; align-items: flex-end; margin-top: 4px; }
.roster form .field { margin: 0; flex: 1 1 110px; }
.roster form .field.note { flex: 3 1 200px; }
.roster form .error, .roster li > .error { flex-basis: 100%; margin: 0; min-height: 0; }
.tabs { display: flex; gap: 8px; margin-bottom: 16px; }
.week-nav { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-bottom: 12px; flex-wrap: wrap; }
.week-nav strong { font-size: 17px; }
.table-wrap { overflow-x: auto; }
table { border-collapse: collapse; width: 100%; background: var(--card); }
th, td { border: 1px solid var(--line); padding: 8px; text-align: left; vertical-align: top; font-size: 14px; }
th { background: #fafafa; white-space: nowrap; }
td.late { background: var(--late-bg); }
td .chip { display: inline-block; margin: 1px 2px; padding: 2px 7px; border-radius: 6px; background: var(--late-line); color: var(--late-text); font-weight: 600; white-space: nowrap; }
td.num { text-align: right; white-space: nowrap; }
a.student-link { color: var(--accent); text-decoration: none; font-weight: 600; cursor: pointer; }
details summary { cursor: pointer; color: var(--muted); margin-top: 8px; font-size: 14px; }
.students-table input, .students-table select { min-height: 38px; padding: 4px 8px; }
.students-table td { vertical-align: middle; }
.students-table tr.inactive input[type=text] { color: var(--muted); }
.success { color: var(--ok); margin: 4px 0 0; min-height: 1.2em; }
.footer-link { text-align: center; margin-top: 24px; }
.footer-link a { color: var(--muted); font-size: 14px; }