* { box-sizing: border-box; margin: 0; padding: 0; }
:root {
    --bg: #f5f6f8;
    --card: #ffffff;
    --border: #e4e7ec;
    --text: #1a1d23;
    --muted: #6b7280;
    --primary: #10b981;
    --primary-dark: #059669;
    --danger: #ef4444;
    --warning: #f59e0b;
    --success: #10b981;
    --shadow: 0 1px 3px rgba(0,0,0,0.05), 0 1px 2px rgba(0,0,0,0.04);
}
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
    font-size: 15px;
}
.hidden { display: none !important; }

/* === LOGIN === */
.login-body {
    display: flex; align-items: center; justify-content: center;
    min-height: 100vh; padding: 20px;
}
.login-box {
    background: var(--card);
    padding: 40px 32px;
    border-radius: 16px;
    box-shadow: var(--shadow);
    width: 100%; max-width: 380px;
}
.login-box h1 { margin-bottom: 24px; text-align: center; font-size: 22px; }
.login-box label { display: block; margin: 12px 0 6px; font-size: 13px; color: var(--muted); font-weight: 600; }
.login-box input { width: 100%; padding: 12px; border: 1px solid var(--border); border-radius: 8px; font-size: 16px; }
.login-box button { width: 100%; margin-top: 20px; padding: 12px; background: var(--primary); color: white; border: none; border-radius: 8px; font-size: 16px; font-weight: 600; cursor: pointer; }
.login-box button:hover { background: var(--primary-dark); }
.error { background: #fef2f2; color: var(--danger); padding: 10px; border-radius: 8px; margin-bottom: 12px; font-size: 14px; }

/* === LAYOUT === */
.topbar {
    background: var(--card);
    border-bottom: 1px solid var(--border);
    padding: 12px 20px;
    display: flex; align-items: center; justify-content: space-between;
    position: sticky; top: 0; z-index: 10;
}
.brand { font-weight: 700; font-size: 17px; text-decoration: none; color: var(--text); }
.topbar nav { display: flex; gap: 6px; }
.topbar nav a {
    padding: 8px 14px;
    text-decoration: none;
    color: var(--muted);
    font-weight: 500;
    border-radius: 8px;
    font-size: 14px;
}
.topbar nav a:hover { background: var(--bg); color: var(--text); }
.topbar nav a.logout { color: var(--danger); }

.container { max-width: 900px; margin: 0 auto; padding: 24px 20px 60px; }
.page-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 20px; gap: 12px; flex-wrap: wrap; }
.page-header h1 { font-size: 24px; }
.back { display: inline-block; color: var(--muted); text-decoration: none; margin-bottom: 12px; font-size: 14px; }
.back:hover { color: var(--text); }

/* === FORMS / CARDS === */
.card {
    background: var(--card);
    padding: 20px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
}
.card h2 { font-size: 17px; margin-bottom: 12px; }
label { display: block; margin: 12px 0 6px; font-size: 13px; color: var(--muted); font-weight: 600; }
input[type="text"], input[type="number"], input[type="date"], input[type="password"], textarea {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 15px;
    font-family: inherit;
    background: white;
}
input:focus, textarea:focus { outline: none; border-color: var(--primary); }
textarea { resize: vertical; }
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 500px) { .row { grid-template-columns: 1fr; } }
.checkbox-label { display: flex; align-items: center; gap: 8px; cursor: pointer; }
.checkbox-label input { width: auto; }

button, .btn-primary, .btn-small, .btn-danger, .btn-tiny {
    cursor: pointer; font-family: inherit; border: none;
    border-radius: 8px; font-weight: 600; transition: opacity 0.15s;
}
button:hover, .btn-primary:hover { opacity: 0.9; }
.btn-primary {
    background: var(--primary); color: white;
    padding: 10px 18px; font-size: 15px;
    margin-top: 12px;
}
.btn-small { padding: 6px 12px; font-size: 13px; background: var(--bg); color: var(--text); border: 1px solid var(--border); }
.btn-small:hover { background: var(--border); }
.btn-danger { background: var(--danger); color: white; padding: 8px 14px; font-size: 13px; }
.btn-tiny { padding: 2px 8px; font-size: 12px; background: transparent; color: var(--danger); border: 1px solid var(--border); }
.btn-quick-paid {
    background: var(--primary);
    color: white;
    padding: 8px 14px;
    font-size: 14px;
    font-weight: 600;
    box-shadow: 0 1px 2px rgba(16, 185, 129, 0.3);
}
.btn-quick-paid:hover { background: var(--primary-dark); }
.row-actions { display: flex; gap: 8px; align-items: center; flex-shrink: 0; }
.quick-form { display: inline; }

.empty { text-align: center; padding: 40px 20px; color: var(--muted); }

/* === EVENTS LIST === */
.event-list { display: grid; gap: 14px; }
.event-card {
    background: var(--card);
    padding: 18px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    text-decoration: none;
    color: inherit;
    display: block;
    border-left: 4px solid var(--primary);
    transition: transform 0.1s;
}
.event-card:hover { transform: translateY(-1px); }
.event-card.closed { opacity: 0.6; border-left-color: var(--muted); }
.event-head { display: flex; justify-content: space-between; align-items: start; gap: 12px; margin-bottom: 8px; }
.event-head h3 { font-size: 17px; }
.deadline { font-size: 12px; color: var(--muted); white-space: nowrap; }
.deadline.overdue { color: var(--danger); font-weight: 600; }
.event-stats { display: flex; gap: 16px; flex-wrap: wrap; font-size: 13px; color: var(--muted); margin-bottom: 10px; }
.event-stats .done { color: var(--success); font-weight: 600; }
.remaining { font-size: 13px; margin-top: 8px; color: var(--muted); }
.remaining.done { color: var(--success); font-weight: 600; }

/* === PROGRESS === */
.progress {
    height: 6px;
    background: var(--bg);
    border-radius: 3px;
    overflow: hidden;
}
.progress.big { height: 10px; margin: 16px 0 6px; }
.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--primary-dark));
    transition: width 0.3s;
}
.progress-label { text-align: center; color: var(--muted); font-size: 13px; margin-bottom: 16px; }

/* === SUMMARY === */
.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 12px;
    margin: 20px 0;
}
.summary-card {
    background: var(--card);
    padding: 14px;
    border-radius: 10px;
    box-shadow: var(--shadow);
    text-align: center;
}
.summary-label { font-size: 11px; color: var(--muted); text-transform: uppercase; letter-spacing: 0.5px; font-weight: 600; }
.summary-value { font-size: 22px; font-weight: 700; margin-top: 4px; }
.summary-card.highlight .summary-value { color: var(--primary); }
.summary-card.warning .summary-value { color: var(--warning); }
.summary-card.success .summary-value { color: var(--success); }
.summary-card.danger .summary-value { color: var(--danger); }

.notes-box { background: #fffbeb; border-left: 4px solid var(--warning); padding: 12px 16px; border-radius: 8px; margin-bottom: 16px; font-size: 14px; }

/* === STUDENTS LIST IN EVENT === */
h2 { font-size: 18px; margin: 24px 0 12px; }
.students-list { display: flex; flex-direction: column; gap: 8px; }
.student-row {
    background: var(--card);
    padding: 12px 16px;
    border-radius: 10px;
    box-shadow: var(--shadow);
    display: flex; justify-content: space-between; align-items: center;
    gap: 12px;
    border-left: 4px solid var(--border);
}
.student-row.status-paid { border-left-color: var(--success); }
.student-row.status-partial { border-left-color: var(--warning); }
.student-row.status-unpaid { border-left-color: var(--danger); }
.student-row.status-absent { border-left-color: var(--muted); opacity: 0.7; }
.student-main { flex: 1; min-width: 0; }
.student-name { font-weight: 600; font-size: 15px; }
.student-status { font-size: 13px; color: var(--muted); margin-top: 2px; }
.student-status .ok { color: var(--success); font-weight: 600; }
.student-status .partial { color: var(--warning); font-weight: 600; }
.student-status .unpaid { color: var(--danger); }
.student-status .overpaid { color: var(--primary); font-weight: 600; }
.student-status .absent-text { font-style: italic; }

.student-detail {
    background: var(--card);
    padding: 16px;
    border-radius: 10px;
    margin-top: -4px;
    margin-bottom: 8px;
    border: 1px solid var(--border);
    border-top: none;
    border-radius: 0 0 10px 10px;
}
.payment-form { margin-bottom: 16px; }
.absence-form { display: flex; gap: 8px; margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--border); }
.absence-form input { flex: 1; }

.payment-history { margin-top: 16px; padding-top: 12px; border-top: 1px solid var(--border); }
.payment-history h4 { font-size: 13px; color: var(--muted); margin-bottom: 8px; }
.payment-row {
    display: flex; gap: 10px; align-items: center;
    padding: 6px 0; font-size: 13px;
    border-bottom: 1px dashed var(--border);
}
.payment-row:last-child { border-bottom: none; }
.payment-row .note { color: var(--muted); flex: 1; font-style: italic; }

/* === STUDENTS PAGE === */
.students-table { width: 100%; border-collapse: collapse; }
.students-table th, .students-table td { padding: 10px; text-align: left; border-bottom: 1px solid var(--border); font-size: 14px; }
.students-table th { font-weight: 600; color: var(--muted); font-size: 12px; text-transform: uppercase; }
.students-table tr.inactive { opacity: 0.5; }
.students-table .actions { text-align: right; white-space: nowrap; }
.students-table .actions form { display: inline-block; margin-left: 4px; }
.inline-edit { border: none; background: transparent; padding: 4px; font-size: 14px; width: 100%; }
.inline-edit:focus { background: var(--bg); border-radius: 4px; }
.hint { color: var(--muted); font-size: 13px; text-align: center; margin-top: 12px; }

/* === HISTORY TABLE === */
.history-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.history-table th, .history-table td { padding: 8px; text-align: left; border-bottom: 1px solid var(--border); }
.history-table th { color: var(--muted); font-weight: 600; font-size: 11px; text-transform: uppercase; }