:root {
    /* Light theme colors */
    --bg-primary: #f5f5f5;
    --bg-secondary: #ffffff;
    --bg-header: #2c3e50;
    --bg-header-hover: #34495e;
    --text-primary: #333333;
    --text-secondary: #555555;
    --text-muted: #666666;
    --text-header: #ecf0f1;
    --text-link: #ecf0f1;
    --border-color: #dddddd;
    --border-light: #eeeeee;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --btn-primary: #3498db;
    --btn-primary-hover: #2980b9;
    --btn-success: #27ae60;
    --btn-success-hover: #219a52;
    --btn-danger: #e74c3c;
    --btn-danger-hover: #c0392b;
    --btn-secondary: #95a5a6;
    --btn-secondary-hover: #7f8c8d;
    --table-hover: #f8f9fa;
    --table-header-bg: #f8f9fa;
    --status-pending-bg: #fff3cd;
    --status-pending-text: #856404;
    --status-processing-bg: #d1ecf1;
    --status-processing-text: #0c5460;
    --status-completed-bg: #d4edda;
    --status-completed-text: #155724;
    --status-failed-bg: #f8d7da;
    --status-failed-text: #721c24;
    --alert-success-bg: #d4edda;
    --alert-success-text: #155724;
    --alert-success-border: #c3e6cb;
    --alert-error-bg: #f8d7da;
    --alert-error-text: #721c24;
    --alert-error-border: #f5c6cb;
    --form-section-bg: #f8f9fa;
    --email-type-fields-bg: #f8f9fa;
    --email-type-fields-border: #007bff;
    --stat-number: #3498db;
    --modal-overlay: rgba(0, 0, 0, 0.5);
    --close-color: #aaaaaa;
    --close-hover: #000000;
    --spinner-bg: #f3f3f3;
    --theme-toggle-bg: rgba(255, 255, 255, 0.2);
    --theme-toggle-hover: rgba(255, 255, 255, 0.3);
}

[data-theme="dark"] {
    /* Dark theme colors */
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-header: #1e1e1e;
    --bg-header-hover: #2d2d2d;
    --text-primary: #e0e0e0;
    --text-secondary: #b0b0b0;
    --text-muted: #888888;
    --text-header: #ecf0f1;
    --text-link: #ecf0f1;
    --border-color: #444444;
    --border-light: #333333;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --btn-primary: #3498db;
    --btn-primary-hover: #2980b9;
    --btn-success: #27ae60;
    --btn-success-hover: #219a52;
    --btn-danger: #e74c3c;
    --btn-danger-hover: #c0392b;
    --btn-secondary: #6c757d;
    --btn-secondary-hover: #5a6268;
    --table-hover: #2d2d2d;
    --table-header-bg: #262626;
    --status-pending-bg: #3d3612;
    --status-pending-text: #d4a017;
    --status-processing-bg: #1c3a41;
    --status-processing-text: #4fc3f7;
    --status-completed-bg: #1e3a25;
    --status-completed-text: #66bb6a;
    --status-failed-bg: #3d1c1c;
    --status-failed-text: #e57373;
    --alert-success-bg: #1e3a25;
    --alert-success-text: #66bb6a;
    --alert-success-border: #2e4a35;
    --alert-error-bg: #3d1c1c;
    --alert-error-text: #e57373;
    --alert-error-border: #4d2c2c;
    --form-section-bg: #262626;
    --email-type-fields-bg: #262626;
    --email-type-fields-border: #3498db;
    --stat-number: #3498db;
    --modal-overlay: rgba(0, 0, 0, 0.7);
    --close-color: #999999;
    --close-hover: #cccccc;
    --spinner-bg: #2d2d2d;
    --theme-toggle-bg: rgba(255, 255, 255, 0.1);
    --theme-toggle-hover: rgba(255, 255, 255, 0.2);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    background: var(--bg-header);
    color: var(--text-header);
    padding: 1rem 0;
    margin-bottom: 2rem;
    transition: background-color 0.3s ease;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

h1 {
    font-size: 1.8rem;
    font-weight: 600;
}

.nav-links {
    display: flex;
    gap: 20px;
}

.nav-links a {
    color: var(--text-link);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 4px;
    transition: background-color 0.2s;
}

.nav-links a:hover, .nav-links a.active {
    background-color: var(--bg-header-hover);
}

.card {
    background: var(--bg-secondary);
    border-radius: 8px;
    box-shadow: 0 2px 4px var(--shadow-color);
    padding: 24px;
    margin-bottom: 24px;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.card h2 {
    color: var(--text-primary);
    margin-bottom: 16px;
    font-size: 1.4rem;
    font-weight: 600;
}

.btn {
    background: var(--btn-primary);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.2s;
    text-decoration: none;
    display: inline-block;
}

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

.btn-success {
    background: var(--btn-success);
}

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

.btn-danger {
    background: var(--btn-danger);
}

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

.btn-secondary {
    background: var(--btn-secondary);
}

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

.btn-group {
    display: flex;
    gap: 8px;
}

.btn-group .btn {
    padding: 8px 16px;
    font-size: 13px;
}

.btn-group .btn.active {
    background: var(--btn-primary);
}

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

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    margin-bottom: 4px;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 14px;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    transition: border-color 0.3s ease, background-color 0.3s ease, color 0.3s ease;
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 16px;
}

.table th,
.table td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-light);
}

.table th {
    background: var(--table-header-bg);
    font-weight: 600;
    color: var(--text-secondary);
}

.table tr:hover {
    background: var(--table-hover);
}

.status {
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
    text-transform: uppercase;
}

.status-pending {
    background: var(--status-pending-bg);
    color: var(--status-pending-text);
}

.status-processing {
    background: var(--status-processing-bg);
    color: var(--status-processing-text);
}

.status-completed {
    background: var(--status-completed-bg);
    color: var(--status-completed-text);
}

.status-failed {
    background: var(--status-failed-bg);
    color: var(--status-failed-text);
}

.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: var(--modal-overlay);
}

.modal-content {
    background-color: var(--bg-secondary);
    margin: 5% auto;
    padding: 20px;
    border: none;
    border-radius: 8px;
    width: 90%;
    max-width: 600px;
    max-height: 80vh;
    overflow-y: auto;
    transition: background-color 0.3s ease;
}

.close {
    color: var(--close-color);
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
}

.close:hover {
    color: var(--close-hover);
}

.alert {
    padding: 12px 16px;
    border-radius: 4px;
    margin-bottom: 16px;
}

.alert-success {
    background: var(--alert-success-bg);
    color: var(--alert-success-text);
    border: 1px solid var(--alert-success-border);
}

.alert-error {
    background: var(--alert-error-bg);
    color: var(--alert-error-text);
    border: 1px solid var(--alert-error-border);
}

.form-section {
    margin-top: 24px;
    padding-top: 20px;
    border-top: 1px solid var(--border-light);
}

.form-section h3 {
    margin: 0 0 16px 0;
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
}

.form-group textarea {
    min-height: 60px;
    resize: vertical;
}

.email-type-fields {
    margin: 16px 0;
    padding: 16px;
    background: var(--email-type-fields-bg);
    border-radius: 4px;
    border-left: 4px solid var(--email-type-fields-border);
    transition: background-color 0.3s ease;
}

.loading {
    display: none;
    text-align: center;
    padding: 20px;
}

.spinner {
    border: 4px solid var(--spinner-bg);
    border-top: 4px solid var(--btn-primary);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 0 auto 10px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.stat-card {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px var(--shadow-color);
    text-align: center;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    color: var(--stat-number);
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 4px;
}

/* Theme Toggle Button */
.theme-toggle {
    background: var(--theme-toggle-bg);
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
    color: var(--text-header);
    font-size: 18px;
    margin-left: 20px;
}

.theme-toggle:hover {
    background: var(--theme-toggle-hover);
    transform: scale(1.05);
}

.theme-toggle:active {
    transform: scale(0.95);
}

@media (max-width: 768px) {
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .header-content {
        flex-direction: column;
        gap: 10px;
    }
    
    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .table {
        font-size: 14px;
    }
    
    .table th,
    .table td {
        padding: 8px;
    }
}