:root {
    --bg: #f4f6f8;
    --card: #ffffff;
    --ink: #1c2733;
    --muted: #6b7886;
    --line: #e2e8f0;
    --primary: #2563eb;
    --primary-d: #1d4ed8;
    --green: #16a34a;
    --green-bg: #dcfce7;
    --red: #dc2626;
    --warn: #d97706;
    --shadow: 0 1px 3px rgba(0,0,0,.08);
}
* { box-sizing: border-box; }
body {
    margin: 0; background: var(--bg); color: var(--ink);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: 15px; line-height: 1.5;
}
.container { max-width: 1080px; margin: 0 auto; padding: 24px 18px 60px; }
h1 { font-size: 1.6rem; margin: .2em 0 .6em; }
h2 { font-size: 1.15rem; margin: 0 0 .5em; }
a { color: var(--primary); }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.r { text-align: right; }

/* Topbar */
.topbar {
    background: var(--card); border-bottom: 1px solid var(--line);
    padding: 10px 18px; display: flex; flex-wrap: wrap; align-items: center; gap: 12px;
    box-shadow: var(--shadow); position: sticky; top: 0; z-index: 10;
}
.brand { font-weight: 700; font-size: 1.05rem; }
.nav { display: flex; flex-wrap: wrap; gap: 4px; margin-left: auto; }
.nav a {
    padding: 6px 11px; border-radius: 7px; text-decoration: none;
    color: var(--ink); font-size: .92rem;
}
.nav a:hover { background: var(--bg); }
.nav a.on { background: var(--primary); color: #fff; }
.nav a.logout { color: var(--red); }

/* Cards */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px,1fr)); gap: 12px; margin: 16px 0 28px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 16px; box-shadow: var(--shadow); }
.card.big { grid-column: span 2; background: linear-gradient(135deg,#2563eb,#1e40af); color: #fff; border: none; }
.card.big .card-label { color: #dbe5ff; }
.card-label { font-size: .8rem; color: var(--muted); text-transform: uppercase; letter-spacing: .04em; }
.card-value { font-size: 1.5rem; font-weight: 700; margin-top: 4px; }
.card-value.neg { color: #fecaca; }
.card-value.warn, .warn { color: var(--warn); }

/* Sections */
section { margin-bottom: 28px; }
.box { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 18px; box-shadow: var(--shadow); }
.section-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }

/* Tables */
.table-wrap { overflow-x: auto; border-radius: 10px; border: 1px solid var(--line); }
table { border-collapse: collapse; width: 100%; background: var(--card); }
.grid th, .grid td { border: 1px solid var(--line); padding: 7px 9px; text-align: center; white-space: nowrap; }
.grid th { background: #f0f4f8; font-weight: 600; font-size: .85rem; }
.grid td.name, .grid th.sticky { text-align: left; }
.sticky { position: sticky; left: 0; background: var(--card); z-index: 2; }
.grid th.sticky { background: #f0f4f8; }
.cell.paid { background: var(--green-bg); color: var(--green); font-weight: 700; }
.cell.unpaid { color: #cbd5e1; }
.cellbtn { background: none; border: none; width: 100%; height: 100%; cursor: pointer; font-size: 1rem; padding: 2px; color: inherit; }
.cell.paid .cellbtn { color: var(--green); }

.list { border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.list th, .list td { padding: 9px 12px; text-align: left; border-bottom: 1px solid var(--line); }
.list th { background: #f0f4f8; font-size: .85rem; }
.list tr:last-child td { border-bottom: none; }

/* Forms */
.inline-form { display: inline-flex; gap: 6px; align-items: center; margin: 0; }
.row-form { display: flex; flex-wrap: wrap; gap: 12px; align-items: flex-end; }
.row-form label, .stack-form label { display: flex; flex-direction: column; font-size: .82rem; color: var(--muted); gap: 3px; }
.stack-form { display: flex; flex-direction: column; gap: 12px; max-width: 360px; }
input, select { padding: 8px 10px; border: 1px solid var(--line); border-radius: 8px; font-size: .95rem; background: #fff; color: var(--ink); }
input.narrow { width: 110px; }
input:focus, select:focus { outline: 2px solid var(--primary); border-color: var(--primary); }

.btn { padding: 8px 14px; border: 1px solid var(--line); background: #fff; border-radius: 8px; cursor: pointer; font-size: .9rem; color: var(--ink); }
.btn:hover { background: var(--bg); }
.btn.primary { background: var(--primary); color: #fff; border-color: var(--primary); }
.btn.primary:hover { background: var(--primary-d); }
.btn.small { padding: 5px 9px; font-size: .82rem; }
.btn.danger { color: var(--red); border-color: #f3c9c9; }
.btn.danger:hover { background: #fef2f2; }

.year-select select { min-width: 90px; }

/* Misc */
.ok { background: var(--green-bg); color: #166534; padding: 10px 14px; border-radius: 8px; }
.error { background: #fef2f2; color: var(--red); padding: 10px 14px; border-radius: 8px; }
.link-box { display: block; background: #0f172a; color: #7dd3fc; padding: 10px 14px; border-radius: 8px; font-family: ui-monospace, monospace; word-break: break-all; margin: 8px 0; }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.public-head { text-align: center; margin-bottom: 8px; }
.public-head h1 { margin-bottom: 0; }
.login-box { max-width: 340px; margin: 60px auto; background: var(--card); padding: 28px; border-radius: 14px; box-shadow: var(--shadow); text-align: center; }
.login-box form { display: flex; flex-direction: column; gap: 14px; margin-top: 16px; text-align: left; }
.login-box label { display: flex; flex-direction: column; gap: 5px; font-size: .85rem; color: var(--muted); }
.footer { text-align: center; margin-top: 30px; }

@media (max-width: 640px) {
    .card.big { grid-column: span 2; }
    .two-col { grid-template-columns: 1fr; }
    .nav { width: 100%; margin-left: 0; }
}