:root {
    --primary: #2563eb;
    --primary-dark: #1e40af;
    --bg: #f3f4f6;
    --card-bg: #ffffff;
    --text-main: #1f2937;
    --text-light: #6b7280;
    --danger: #dc2626;
    --warning: #d97706;
    --success: #059669;
    --border: #e5e7eb;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg);
    color: var(--text-main);
    margin: 0;
    padding: 20px;
    line-height: 1.5;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: var(--card-bg);
    border-radius: 12px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

header {
    background: var(--primary);
    color: white;
    padding: 20px;
    text-align: center;
}

header h1 {
    margin: 0;
    font-size: 1.5rem;
    font-weight: 600;
}

header p {
    margin: 5px 0 0;
    font-size: 0.9rem;
    opacity: 0.9;
}

.section {
    padding: 20px;
    border-bottom: 1px solid var(--border);
}

.section-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-dark);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

@media (max-width: 600px) {
    .form-grid {
        grid-template-columns: 1fr;
    }
}

.form-group {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
    font-size: 0.95rem;
}

.hint {
    font-size: 0.8rem;
    color: var(--text-light);
    margin-top: 2px;
}

input[type="number"],
input[type="datetime-local"] {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 1rem;
    box-sizing: border-box;
    transition: border-color 0.2s;
}

input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.risk-factors {
    background: #f8fafc;
    padding: 15px;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    font-weight: normal;
}

.checkbox-label input {
    width: 18px;
    height: 18px;
}

.btn-calculate {
    width: 100%;
    background: var(--primary);
    color: white;
    border: none;
    padding: 15px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-calculate:hover {
    background: var(--primary-dark);
}

.btn-calculate:disabled {
    background: #cbd5e1;
    cursor: not-allowed;
}

#result-area {
    display: none;
    padding: 0;
}

.result-header {
    background: #eff6ff;
    padding: 15px 20px;
    border-bottom: 1px solid var(--border);
}

.result-summary {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-dark);
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    padding: 20px;
}

.result-card {
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 15px;
}

.card-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 10px;
}

.card-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 5px;
}

.card-sub {
    font-size: 0.9rem;
    color: var(--text-light);
}

.risk-badge {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
}

.risk-high { background: #fee2e2; color: #991b1b; }
.risk-mid { background: #fef3c7; color: #92400e; }
.risk-low { background: #d1fae5; color: #065f46; }

.exchange-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 10px;
}
.exchange-table td {
    padding: 6px 0;
    border-bottom: 1px solid #f3f4f6;
}
.exchange-table td:last-child {
    text-align: right;
    font-weight: 600;
}

footer {
    max-width: 800px;
    margin: 20px auto 0;
    text-align: center;
    color: var(--text-light);
    font-size: 0.85rem;
    padding: 0 10px;
}

.footer-content {
    border-top: 1px solid var(--border);
    padding-top: 20px;
}

.disclaimer {
    margin-bottom: 8px;
}

.copyright {
    margin-top: 0;
    font-size: 0.8rem;
    opacity: 0.8;
}

/* 動態顯示控制 (Dynamic visibility control) */
.hidden { display: none !important; }