:root { --blue: #2f6fed; --red: #d93025; --green: #188038; --grey: #5f6368; --bg: #f6f7f9; }
* { box-sizing: border-box; }
body { margin: 0; font: 17px/1.4 -apple-system, system-ui, "Segoe UI", Roboto, sans-serif; background: var(--bg); color: #202124; }
main { max-width: 640px; margin: 0 auto; padding: 16px 16px 96px; }
h1 { font-size: 24px; margin: 8px 0 16px; }
a { color: var(--blue); }
.card { background: #fff; border-radius: 12px; padding: 14px; margin-bottom: 12px; border-left: 6px solid var(--grey); }
.card.debt { border-left-color: var(--red); } .card.ahead { border-left-color: var(--green); }
.card .title { text-decoration: none; color: inherit; }
.big { font-size: 20px; margin: 6px 0 10px; }
.muted { color: var(--grey); font-size: 15px; }
.error { background: #fce8e6; color: var(--red); padding: 10px; border-radius: 8px; }
.row { display: flex; gap: 8px; flex-wrap: wrap; }
.row input { flex: 1; min-width: 90px; }
.stack { display: flex; flex-direction: column; gap: 12px; }
.stack label { display: flex; flex-direction: column; gap: 4px; }
input, select, textarea, button, .button { font: inherit; padding: 10px 12px; border-radius: 8px; border: 1px solid #dadce0; }
button, .button { background: var(--blue); color: #fff; border: 0; text-decoration: none; display: inline-block; cursor: pointer; }
button.secondary { background: #e8eaed; color: #202124; } button.danger { background: var(--red); }
.total { font-size: 18px; }
table { width: 100%; border-collapse: collapse; background: #fff; border-radius: 12px; overflow: hidden; }
td, th { padding: 8px; border-bottom: 1px solid #eee; text-align: left; font-size: 15px; }
td.num, th.num { text-align: right; white-space: nowrap; }
.tabs { position: fixed; bottom: 0; left: 0; right: 0; display: flex; background: #fff; border-top: 1px solid #dadce0; padding-bottom: env(safe-area-inset-bottom); }
.tabs a { flex: 1; text-align: center; padding: 14px 4px; text-decoration: none; font-size: 14px; }
.day { margin: 16px 0 6px; font-weight: 600; }
.lesson { display: flex; justify-content: space-between; background: #fff; padding: 12px; border-radius: 10px; margin-bottom: 6px; text-decoration: none; color: inherit; }
.lesson.cancelled, .lesson.late { opacity: .6; text-decoration: line-through; }
details { background: #fff; border-radius: 12px; padding: 12px; margin-bottom: 12px; }