/* ===== Reset & base ===== */
body {
    margin: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background-color: #f5f6f8;
    color: #222;
}

a {
    color: #1f6feb;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* ===== Layout ===== */
.header {
    background: #ffffff;
    border-bottom: 1px solid #ddd;
    padding: 15px 30px;
}

.nav a {
    margin-right: 15px;
    font-weight: 500;
}

.container {
    max-width: 1100px;
    margin: 30px auto;
    padding: 0 20px;
}

/* ===== Cards ===== */
.card {
    background: #ffffff;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.06);
    margin-bottom: 20px;
}

/* ===== Grid ===== */
.grid {
    display: grid;
    gap: 20px;
}

.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

/* ===== Tables ===== */
table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 10px;
    border-bottom: 1px solid #e0e0e0;
    text-align: left;
}

th {
    background: #fafafa;
    font-weight: 600;
}

/* ===== Buttons ===== */
button {
    padding: 8px 14px;
    border: none;
    border-radius: 6px;
    background: #1f6feb;
    color: white;
    cursor: pointer;
}

button.secondary {
    background: #6c757d;
}

button:hover {
    opacity: 0.9;
}

/* ===== Status ===== */
.paid {
    color: #198754;
    font-weight: 500;
}

.unpaid {
    color: #dc3545;
    font-weight: 500;
}