:root {
    --bg: #f4f6f9;
    --card: #ffffff;
    --text: #1f2937;
    --muted: #6b7280;
    --border: #e5e7eb;
    --primary: #1f4e78;
    --primary-dark: #163c5c;
    --primary-soft: #e6eef7;
    --success: #16794f;
    --success-bg: #e7f7ef;
    --danger: #b3261e;
    --danger-bg: #fdecea;
    --warn: #9c5700;
    --warn-bg: #fce4d6;
    --radius: 10px;
    --shadow: 0 1px 3px rgba(16, 24, 40, 0.06);
}

[data-theme="dark"] {
    --bg: #0f1520;
    --card: #171f2e;
    --text: #e5e9f0;
    --muted: #93a0b4;
    --border: #2a3446;
    --primary: #5b9bd5;
    --primary-dark: #7fb2e0;
    --primary-soft: #1c2c40;
    --success: #4ade80;
    --success-bg: #113321;
    --danger: #f87171;
    --danger-bg: #3a1719;
    --warn: #fbbf24;
    --warn-bg: #3a2a10;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, "Segoe UI", Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
    transition: background 0.15s ease, color 0.15s ease;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 24px 20px 60px;
}

.topbar {
    background: var(--primary);
    color: #fff;
    box-shadow: var(--shadow);
}
.topbar-guest { background: var(--card); color: var(--text); border-bottom: 1px solid var(--border); }
.topbar-guest .brand { color: var(--text); }
.topbar-inner {
    max-width: 1000px;
    margin: 0 auto;
    padding: 14px 20px;
    display: flex;
    align-items: center;
    gap: 24px;
    flex-wrap: wrap;
}
.topbar .brand { color: #fff; font-weight: 700; font-size: 1.05rem; margin-right: auto; }
.topbar nav a { color: #dbe7f2; margin-right: 16px; position: relative; }
.topbar nav a:hover { color: #fff; }
.topbar-user { display: flex; align-items: center; gap: 10px; color: #dbe7f2; font-size: 0.9rem; }
.topbar-guest .topbar-user { color: var(--text); }
.topbar-user small { opacity: 0.8; }
.nav-badge {
    display: inline-block;
    background: #e05252;
    color: #fff;
    border-radius: 999px;
    font-size: 0.68rem;
    padding: 1px 6px;
    font-weight: 700;
    vertical-align: top;
}
.theme-toggle {
    background: rgba(255,255,255,0.15);
    border: none;
    color: inherit;
    width: 30px; height: 30px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1rem;
    display: inline-flex; align-items: center; justify-content: center;
}
.topbar-guest .theme-toggle { background: var(--primary-soft); }
.theme-toggle:hover { filter: brightness(1.1); }

.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

h1 { font-size: 1.5rem; margin: 0 0 6px; }
h2 { font-size: 1.15rem; margin: 0 0 12px; }
.subtitle { color: var(--muted); margin: 0 0 20px; }

table { width: 100%; border-collapse: collapse; font-size: 0.92rem; }
th, td { padding: 10px 12px; text-align: left; border-bottom: 1px solid var(--border); vertical-align: top; }
th { color: var(--muted); font-weight: 600; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.03em; }
tr:last-child td { border-bottom: none; }
.num { text-align: right; font-variant-numeric: tabular-nums; white-space: nowrap; }

.btn {
    display: inline-block;
    background: var(--primary);
    color: #fff !important;
    padding: 9px 16px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    font-size: 0.9rem;
    text-decoration: none;
}
.btn:hover { background: var(--primary-dark); }
.btn-small { padding: 6px 12px; font-size: 0.82rem; }
.btn-danger { background: var(--danger); }
.btn-secondary { background: transparent; color: var(--primary) !important; border: 1px solid var(--border); }
.btn-secondary:hover { background: var(--primary-soft); }

form .field { margin-bottom: 14px; }
label { display: block; font-size: 0.85rem; color: var(--muted); margin-bottom: 4px; }
input[type=text], input[type=password], input[type=date], input[type=number], input[type=file], select, textarea {
    width: 100%;
    padding: 9px 10px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 0.95rem;
    font-family: inherit;
    background: var(--card);
    color: var(--text);
}
textarea { min-height: 70px; resize: vertical; }
.form-row { display: flex; gap: 14px; flex-wrap: wrap; }
.form-row .field { flex: 1; min-width: 160px; }

.badge { display: inline-block; padding: 2px 9px; border-radius: 999px; font-size: 0.75rem; font-weight: 600; }
.badge-limit { background: var(--success-bg); color: var(--success); }
.badge-payment { background: var(--primary-soft); color: var(--primary); }
.badge-unverified { background: var(--warn-bg); color: var(--warn); }

.flash { padding: 12px 16px; border-radius: 8px; margin-bottom: 16px; font-size: 0.9rem; }
.flash-success { background: var(--success-bg); color: var(--success); }
.flash-error { background: var(--danger-bg); color: var(--danger); }
.flash-info { background: var(--primary-soft); color: var(--primary); }

.due-figure { font-size: 1.6rem; font-weight: 700; }
.due-figure.zero { color: var(--muted); }
.grid-clients { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; }
.client-card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.client-card h3 { margin: 0 0 8px; font-size: 1.05rem; color: var(--text); }
.client-card .due-figure { margin: 6px 0 2px; }
.client-card .bdt { color: var(--muted); font-size: 0.85rem; margin-bottom: 10px; }
.unverified-flag { color: var(--warn); font-size: 0.8rem; }

.sitefooter { text-align: center; color: var(--muted); font-size: 0.8rem; padding: 20px; }

.login-wrap { max-width: 380px; margin: 80px auto; }
.section-note { color: var(--muted); font-size: 0.85rem; margin: -6px 0 16px; }

.filter-bar { display: flex; gap: 10px; flex-wrap: wrap; align-items: flex-end; margin-bottom: 16px; }
.filter-bar .field { margin-bottom: 0; min-width: 140px; }
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 14px; }
.stat-box { background: var(--primary-soft); border-radius: 8px; padding: 14px; }
.stat-box .label { font-size: 0.78rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.03em; }
.stat-box .value { font-size: 1.3rem; font-weight: 700; margin-top: 4px; }

@media (max-width: 640px) {
    .topbar-inner { flex-direction: column; align-items: flex-start; gap: 8px; }
    table, thead, tbody, th, td, tr { display: block; }
    thead { display: none; }
    tr { border: 1px solid var(--border); border-radius: 8px; margin-bottom: 10px; padding: 8px; }
    td { border-bottom: none; padding: 4px 6px; }
    td::before { content: attr(data-label); display: block; font-size: 0.7rem; color: var(--muted); text-transform: uppercase; }
    .num { text-align: left; }
}