:root {
    --bg: #f4f6f8;
    --panel: #ffffff;
    --text: #17202a;
    --muted: #667085;
    --border: #d0d5dd;
    --primary: #1f4e79;
    --primary-dark: #173b5c;
    --danger: #b42318;
    --success: #027a48;
}

* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: var(--bg);
    color: var(--text);
}

a { color: inherit; }
.app-shell { display: flex; min-height: 100vh; }
.sidebar {
    width: 250px;
    background: #102a43;
    color: #fff;
    padding: 20px 14px;
}
.brand {
    font-weight: 700;
    font-size: 20px;
    margin-bottom: 28px;
    padding: 0 8px;
}
.sidebar nav a,
.sidebar .nav-heading {
    display: block;
    padding: 11px 12px;
    border-radius: 8px;
    margin-bottom: 5px;
    text-decoration: none;
}
.sidebar nav a:hover { background: rgba(255,255,255,.12); }
.sidebar .disabled { opacity: .55; cursor: not-allowed; }
.sidebar .nav-heading { color: #bcccdc; font-size: 13px; margin-top: 18px; }
.main-content { flex: 1; padding: 24px; }
.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}
.topbar h1 { margin: 0; font-size: 28px; }
.topbar p { margin: 4px 0 0; color: var(--muted); }
.card {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 18px;
    margin-bottom: 18px;
    box-shadow: 0 1px 2px rgba(16, 24, 40, .06);
}
.grid { display: grid; gap: 16px; }
.grid-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.stat .label { color: var(--muted); font-size: 14px; }
.stat .value { font-size: 30px; font-weight: 700; margin-top: 8px; }
.table-wrapper { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; background: #fff; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--border); white-space: nowrap; }
th { background: #f9fafb; font-weight: 700; }
.form-row { display: grid; gap: 10px; margin-bottom: 14px; }
label { font-weight: 700; }
input, select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: #fff;
}
.button {
    display: inline-block;
    border: 0;
    border-radius: 8px;
    padding: 10px 14px;
    background: var(--primary);
    color: #fff;
    text-decoration: none;
    cursor: pointer;
    font-weight: 700;
}
.button:hover { background: var(--primary-dark); }
.button-secondary { background: #475467; }
.alert { padding: 12px 14px; border-radius: 8px; margin-bottom: 16px; }
.alert-danger { background: #fef3f2; color: var(--danger); border: 1px solid #fecdca; }
.alert-success { background: #ecfdf3; color: var(--success); border: 1px solid #abefc6; }
.login-page {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}
.login-card { width: min(440px, 100%); }
@media (max-width: 900px) {
    .app-shell { display: block; }
    .sidebar { width: 100%; }
    .grid-4, .grid-3 { grid-template-columns: 1fr; }
}
textarea {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: #fff;
    font-family: Arial, Helvetica, sans-serif;
}
.card.success { background: #ecfdf3; color: var(--success); border-color: #abefc6; }
.card.error { background: #fef3f2; color: var(--danger); border-color: #fecdca; }
.muted { color: var(--muted); font-size: 14px; }
.form-inline { display: flex; gap: 10px; align-items: center; }
.form-inline input { max-width: 420px; }
.button.small { padding: 6px 9px; font-size: 13px; }
.button.danger { background: var(--danger); }
.button.danger:hover { background: #7a271a; }
.button.secondary { background: #475467; }
.button.secondary:hover { background: #344054; }