:root {
    /* Light mode colors */
    --primary-color: #4CAF50;
    --primary-hover: #45a049;
    --secondary-color: #2196F3;
    --secondary-hover: #1976D2;
    --background-color: #f5f5f5;
    --container-background: #ffffff;
    --text-color: #333;
    --text-secondary: #6c757d;
    --header-text-color: #ffffff;
    --border-color: #ddd;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --controls-background: #fdfdfd;
    --controls-border: #e9ecef;
    --input-background: #ffffff;
    --input-focus-shadow: rgba(76, 175, 80, 0.2);
    --message-info-bg: #d1ecf1;
    --message-info-color: #0c5460;
    --message-info-border: #bee5eb;
    --message-error-bg: #f8d7da;
    --message-error-color: #721c24;
    --message-error-border: #f5c6cb;
    --iframe-background: #ffffff;
    --modal-background: rgba(0, 0, 0, 0.5);
    --modal-content-bg: #ffffff;
    --outline-button-bg: transparent;
    --outline-button-border: #4CAF50;
    --outline-button-color: #4CAF50;
    --outline-button-hover-bg: #4CAF50;
    --outline-button-hover-color: #ffffff;

    /* Transition properties */
    --transition-duration: 0.3s;
    --transition-easing: ease;
}

/* Dark mode colors */
[data-theme="dark"] {
    --primary-color: #66bb6a;
    --primary-hover: #5cb85c;
    --secondary-color: #42a5f5;
    --secondary-hover: #1e88e5;
    --background-color: #121212;
    --container-background: #1e1e1e;
    --text-color: #e0e0e0;
    --text-secondary: #b0b0b0;
    --header-text-color: #ffffff;
    --border-color: #404040;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --controls-background: #2a2a2a;
    --controls-border: #404040;
    --input-background: #2a2a2a;
    --input-focus-shadow: rgba(102, 187, 106, 0.3);
    --message-info-bg: #1a3a42;
    --message-info-color: #7dd3fc;
    --message-info-border: #0891b2;
    --message-error-bg: #4a1a1a;
    --message-error-color: #fca5a5;
    --message-error-border: #dc2626;
    --iframe-background: #1e1e1e;
    --modal-background: rgba(0, 0, 0, 0.7);
    --modal-content-bg: #2a2a2a;
    --outline-button-bg: transparent;
    --outline-button-border: #66bb6a;
    --outline-button-color: #66bb6a;
    --outline-button-hover-bg: #66bb6a;
    --outline-button-hover-color: #ffffff;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    min-height: 100vh;
    padding: 20px;
    transition: background-color var(--transition-duration) var(--transition-easing),
                color var(--transition-duration) var(--transition-easing);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: var(--container-background);
    border-radius: 12px;
    box-shadow: 0 8px 32px var(--shadow-color);
    overflow: hidden;
    transition: background-color var(--transition-duration) var(--transition-easing),
                box-shadow var(--transition-duration) var(--transition-easing);
}

.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-hover) 100%);
    color: var(--header-text-color);
    padding: 30px;
    transition: background var(--transition-duration) var(--transition-easing);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 30px;
}

.header-text {
    flex: 1;
    min-width: 300px;
}

.header-stats {
    display: flex;
    gap: 20px;
    margin-top: 15px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: rgba(255, 255, 255, 0.1);
    padding: 10px 15px;
    border-radius: 8px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-number {
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1;
}

.stat-label {
    font-size: 0.8rem;
    opacity: 0.9;
    margin-top: 2px;
}

.header-actions {
    display: flex;
    gap: 10px;
    flex-shrink: 0;
}

.dark-mode-toggle, .help-button {
    background: rgba(255, 255, 255, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.3);
    color: var(--header-text-color);
    padding: 12px 16px;
    border-radius: 25px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all var(--transition-duration) var(--transition-easing);
    backdrop-filter: blur(10px);
    white-space: nowrap;
}

.dark-mode-toggle:hover, .help-button:hover {
    background: rgba(255, 255, 255, 0.3);
    border-color: rgba(255, 255, 255, 0.5);
    transform: translateY(-2px);
}

.dark-mode-toggle:focus, .help-button:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.3);
}

.toggle-icon, .help-icon {
    font-size: 1.2rem;
    transition: transform var(--transition-duration) var(--transition-easing);
}

[data-theme="dark"] .toggle-icon {
    transform: rotate(180deg);
}

[data-theme="dark"] .dark-mode-toggle .toggle-icon::before {
    content: "☀️";
}

.toggle-text, .help-text {
    font-size: 0.85rem;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 8px;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.header p {
    font-size: 1.1rem;
    opacity: 0.95;
    margin-bottom: 0;
}

.controls {
    padding: 25px 30px;
    background: var(--controls-background);
    border-bottom: 1px solid var(--controls-border);
    transition: background-color var(--transition-duration) var(--transition-easing),
                border-color var(--transition-duration) var(--transition-easing);
}

.control-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    align-items: end;
}

.control-item {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.search-container {
    position: relative;
    display: flex;
    align-items: center;
}

.search-container input {
    padding-right: 40px;
}

.clear-search {
    position: absolute;
    right: 10px;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 5px;
    border-radius: 50%;
    transition: all var(--transition-duration) var(--transition-easing);
    font-size: 0.9rem;
}

.clear-search:hover {
    background: var(--border-color);
    color: var(--text-color);
}

.button-group {
    display: flex;
    gap: 10px;
}

.btn {
    padding: 12px 20px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-align: center;
    height: 44px;
    transition: all var(--transition-duration) var(--transition-easing);
    min-width: 100px;
    justify-content: center;
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(76, 175, 80, 0.3);
}

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

.btn-secondary:hover {
    background-color: var(--secondary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.3);
}

.btn-outline {
    background-color: var(--outline-button-bg);
    color: var(--outline-button-color);
    border: 2px solid var(--outline-button-border);
}

.btn-outline:hover {
    background-color: var(--outline-button-hover-bg);
    color: var(--outline-button-hover-color);
    transform: translateY(-2px);
}

.btn-icon {
    font-size: 1.1rem;
}

.btn-text {
    font-size: 0.9rem;
}

label {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.9rem;
    transition: color var(--transition-duration) var(--transition-easing);
}

select, input {
    padding: 12px 14px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    width: 100%;
    background-color: var(--input-background);
    color: var(--text-color);
    transition: all var(--transition-duration) var(--transition-easing);
}

select:focus, input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--input-focus-shadow);
}

.content {
    padding: 30px;
    min-height: 500px;
    transition: background-color var(--transition-duration) var(--transition-easing);
}

.no-selection {
    text-align: center;
    color: var(--text-secondary);
    padding: 60px 20px;
    transition: color var(--transition-duration) var(--transition-easing);
}

.no-selection-content {
    max-width: 400px;
    margin: 0 auto;
}

.no-selection-icon {
    font-size: 4rem;
    margin-bottom: 20px;
    display: block;
    color: var(--primary-color);
    opacity: 0.3;
    transition: color var(--transition-duration) var(--transition-easing);
}

.no-selection h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--text-color);
}

.no-selection p {
    margin-bottom: 25px;
    line-height: 1.6;
}

.no-selection-actions {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.loading {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
    transition: color var(--transition-duration) var(--transition-easing);
}

.loading-content {
    max-width: 300px;
    margin: 0 auto;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

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

.attendance-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.attendance-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    background: var(--controls-background);
    border-radius: 8px;
    border: 1px solid var(--controls-border);
}

.attendance-info h2 {
    font-size: 1.5rem;
    margin-bottom: 5px;
    color: var(--text-color);
}

.attendance-info p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.attendance-actions {
    display: flex;
    gap: 10px;
}

.attendance-frame {
    width: 100%;
    height: 600px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--iframe-background);
    transition: all var(--transition-duration) var(--transition-easing);
}

.message {
    padding: 15px 20px;
    border-radius: 8px;
    margin: 0 0 20px 0;
    border: 1px solid;
    transition: all var(--transition-duration) var(--transition-easing);
    display: flex;
    align-items: center;
    gap: 10px;
}

.error {
    background: var(--message-error-bg);
    color: var(--message-error-color);
    border-color: var(--message-error-border);
}

.info {
    background: var(--message-info-bg);
    color: var(--message-info-color);
    border-color: var(--message-info-border);
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--modal-background);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.modal-content {
    background: var(--modal-content-bg);
    border-radius: 12px;
    max-width: 600px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px var(--shadow-color);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 25px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 1.3rem;
    color: var(--text-color);
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 5px;
    border-radius: 50%;
    transition: all var(--transition-duration) var(--transition-easing);
}

.modal-close:hover {
    background: var(--border-color);
    color: var(--text-color);
}

.modal-body {
    padding: 25px;
}

.help-section {
    margin-bottom: 25px;
}

.help-section:last-child {
    margin-bottom: 0;
}

.help-section h4 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.help-section ul {
    list-style: none;
    padding-left: 0;
}

.help-section li {
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
    line-height: 1.5;
}

.help-section li:last-child {
    border-bottom: none;
}

.help-section strong {
    color: var(--primary-color);
}

kbd {
    background: var(--controls-background);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 2px 6px;
    font-size: 0.8rem;
    font-family: monospace;
    color: var(--text-color);
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .header {
        padding: 20px;
    }

    .header-content {
        flex-direction: column;
        text-align: center;
        gap: 20px;
    }

    .header-text {
        text-align: center;
        min-width: auto;
    }

    .header h1 {
        font-size: 2rem;
    }

    .header-stats {
        justify-content: center;
    }

    .header-actions {
        justify-content: center;
        width: 100%;
    }

    .toggle-text, .help-text {
        display: none;
    }

    .controls {
        padding: 20px;
    }

    .control-group {
        grid-template-columns: 1fr;
        gap: 15px;
    }

    .button-group {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    .content {
        padding: 20px;
    }

    .attendance-header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }

    .attendance-actions {
        justify-content: center;
    }

    .attendance-frame {
        height: 500px;
    }

    .modal-content {
        width: 95%;
        margin: 20px;
    }

    .modal-header, .modal-body {
        padding: 15px;
    }
}

@media (max-width: 480px) {
    .header h1 {
        font-size: 1.8rem;
    }

    .header-stats {
        flex-direction: column;
        gap: 10px;
    }

    .stat-item {
        flex-direction: row;
        justify-content: space-between;
        padding: 8px 12px;
    }

    .stat-number {
        font-size: 1.2rem;
    }

    .btn {
        padding: 10px 15px;
        font-size: 0.9rem;
    }

    .btn-icon {
        font-size: 1rem;
    }

    .btn-text {
        font-size: 0.8rem;
    }
}