* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #4F46E5;
    --primary-light: #6366F1;
    --primary-dark: #4338CA;
    --success-color: #10B981;
    --danger-color: #EF4444;
    --text-primary: #1F2937;
    --text-secondary: #6B7280;
    --bg-color: #F3F4F6;
    --card-bg: #FFFFFF;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

/* 模拟粗体效果 - 解决部分浏览器中文粗体不生效的问题 */
.font-bold {
    -webkit-text-stroke: 0.4px currentColor;
    paint-order: stroke fill;
}

.font-bold-sm {
    -webkit-text-stroke: 0.25px currentColor;
    paint-order: stroke fill;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 600px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

h1 {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 8px;
}

.date-display {
    color: var(--text-secondary);
    font-size: 14px;
}

.cards-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-bottom: 20px;
}

.card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: var(--shadow-md);
    transition: transform 0.2s, box-shadow 0.2s;
    position: relative;
    overflow: hidden;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.card-name {
    font-weight: 600;
    font-size: 18px;
    color: var(--text-primary);
}

.card-actions {
    display: flex;
    gap: 8px;
}

.card-action-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    opacity: 0.6;
    transition: opacity 0.2s;
}

.card-action-btn:hover {
    opacity: 1;
}

.card-info {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
    margin-bottom: 12px;
}

.info-row {
    display: flex;
    justify-content: space-between;
    grid-column: 1 / -1;
}

.info-item {
    font-size: 14px;
    color: var(--text-secondary);
}

.info-value {
    font-weight: 500;
    color: var(--text-primary);
}

.card-footer {
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding-top: 12px;
    border-top: 1px solid #E5E7EB;
}

.footer-dates {
    display: flex;
    justify-content: space-between;
    font-size: 14px;
    background: #F8FAFC;
    border-radius: 8px;
    padding: 10px 12px;
}

.footer-date-item {
    color: var(--text-secondary);
}

.footer-date-item strong {
    color: var(--primary-color);
    font-weight: 600;
}

.footer-main {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.interest-free-days {
    display: flex;
    align-items: center;
    gap: 6px;
    font-weight: 600;
    color: var(--primary-color);
}

.days-badge {
    background: var(--primary-color);
    color: white;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
}

.recommendation {
    font-size: 13px;
    color: var(--success-color);
    font-weight: 500;
}

.add-card-btn {
    width: 100%;
    padding: 16px;
    background: var(--card-bg);
    border: 2px dashed var(--primary-color);
    border-radius: 12px;
    color: var(--primary-color);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all 0.2s;
}

.add-card-btn:hover {
    background: var(--primary-color);
    color: white;
}

.plus-icon {
    font-size: 24px;
    line-height: 1;
}

.config-actions {
    display: flex;
    gap: 12px;
    margin-top: 16px;
}

.config-btn {
    flex: 1;
    padding: 12px 16px;
    background: var(--card-bg);
    border: 1px solid var(--primary-color);
    border-radius: 8px;
    color: var(--primary-color);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.config-btn:hover {
    background: var(--primary-color);
    color: white;
}

.export-container,
.import-container {
    padding: 20px;
}

.export-container textarea,
.import-container textarea {
    width: 100%;
    height: 200px;
    padding: 12px;
    border: 1px solid #D1D5DB;
    border-radius: 8px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 14px;
    line-height: 1.5;
    resize: none;
    margin-bottom: 12px;
}

.import-hint {
    color: var(--text-secondary);
    font-size: 13px;
    margin-bottom: 12px;
}

.import-actions {
    display: flex;
    gap: 12px;
    margin-top: 12px;
}

.import-actions button {
    flex: 1;
    padding: 12px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
}

.success-msg {
    margin-top: 12px;
    padding: 10px;
    background: #D1FAE5;
    border: 1px solid #10B981;
    border-radius: 6px;
    color: #065F46;
    font-size: 14px;
    text-align: center;
}

.error-msg {
    margin-top: 12px;
    padding: 10px;
    background: #FEE2E2;
    border: 1px solid #EF4444;
    border-radius: 6px;
    color: #991B1B;
    font-size: 14px;
    text-align: center;
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--card-bg);
    border-radius: 12px;
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid #E5E7EB;
}

.modal-header h2 {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
}

.close-btn {
    background: none;
    border: none;
    font-size: 28px;
    cursor: pointer;
    color: var(--text-secondary);
    line-height: 1;
}

.card-form {
    padding: 20px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-primary);
    font-size: 14px;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid #D1D5DB;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.color-picker {
    display: flex;
    align-items: center;
    gap: 12px;
}

.color-picker input[type="color"] {
    width: 60px;
    height: 40px;
    padding: 2px;
    cursor: pointer;
}

.color-preview {
    width: 40px;
    height: 40px;
    border-radius: 8px;
    border: 1px solid #D1D5DB;
    display: inline-block;
}

.hidden {
    display: none;
}

.form-actions {
    display: flex;
    gap: 12px;
    margin-top: 24px;
}

.form-actions button {
    flex: 1;
    padding: 12px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

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

.btn-secondary {
    background: #E5E7EB;
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: #D1D5DB;
}

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

.empty-state-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.empty-state-text {
    font-size: 16px;
}

.app-footer {
    text-align: center;
    padding: 20px 0;
    margin-top: 10px;
}

.version-info {
    display: inline-block;
    padding: 6px 12px;
    background: var(--card-bg);
    border-radius: 20px;
    font-size: 12px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: var(--shadow-sm);
}

.version-info:hover {
    background: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-md);
}

#versionNumber {
    font-weight: 600;
}

@media (max-width: 480px) {
    body {
        padding: 12px;
    }

    h1 {
        font-size: 24px;
    }

    .card {
        padding: 16px;
    }

    .card-info {
        grid-template-columns: 1fr;
    }
}