/* CSS Variables for theming */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --secondary-hover: #475569;
    --success-color: #10b981;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -4px rgba(0, 0, 0, 0.2);
    --radius: 12px;
    --radius-sm: 8px;
    --transition: all 0.2s ease;
}

/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
}

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

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 2rem;
}

.logo-section {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.logo {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-sm);
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Main content */
main {
    flex: 1;
}

/* Options Panel */
.options-panel {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border: 1px solid var(--border-color);
}

.options-panel h2 {
    font-size: 1rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 1rem;
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.option {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.option:hover {
    background: var(--surface-light);
}

.option input[type="checkbox"] {
    display: none;
}

.checkbox-custom {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    flex-shrink: 0;
}

.option input[type="checkbox"]:checked + .checkbox-custom {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.option input[type="checkbox"]:checked + .checkbox-custom::after {
    content: '✓';
    color: white;
    font-size: 12px;
    font-weight: bold;
}

.option-text {
    color: var(--text-primary);
    font-size: 0.95rem;
}

/* Editor Section */
.editor-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.editor-panel {
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
    background: var(--surface-light);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: 0.75rem;
}

.panel-header h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.panel-actions {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

textarea {
    width: 100%;
    min-height: 200px;
    padding: 1rem;
    background: var(--surface);
    border: none;
    color: var(--text-primary);
    font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;
    font-size: 0.9rem;
    resize: vertical;
    outline: none;
}

textarea::placeholder {
    color: var(--text-secondary);
}

textarea:focus {
    background: #253145;
}

.size-info {
    padding: 0.5rem 1rem;
    background: var(--surface-light);
    border-top: 1px solid var(--border-color);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.btn svg {
    flex-shrink: 0;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    padding: 0.875rem 2rem;
    font-size: 1rem;
    box-shadow: var(--shadow);
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--surface-light);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

.action-buttons {
    display: flex;
    justify-content: center;
    padding: 0.5rem 0;
}

/* Stats Panel */
.stats-panel {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-top: 1.5rem;
    border: 1px solid var(--border-color);
}

.stats-panel h2 {
    font-size: 1rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 1rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-bottom: 1rem;
}

.stat-card {
    background: var(--surface-light);
    padding: 1rem;
    border-radius: var(--radius-sm);
    text-align: center;
}

.stat-card.highlight {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.2), rgba(99, 102, 241, 0.2));
    border: 1px solid var(--success-color);
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

.stat-value {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.stat-card.highlight .stat-value {
    color: var(--success-color);
}

.compression-bar {
    height: 8px;
    background: var(--surface-light);
    border-radius: 4px;
    overflow: hidden;
}

.compression-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--success-color), var(--primary-color));
    border-radius: 4px;
    width: 0%;
    transition: width 0.5s ease;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem 1rem;
    margin-top: 2rem;
    border-top: 1px solid var(--border-color);
}

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

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

footer a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* Toast notifications */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--surface);
    color: var(--text-primary);
    padding: 1rem 1.5rem;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

.toast.success {
    border-color: var(--success-color);
}

.toast.error {
    border-color: #ef4444;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }

    h1 {
        font-size: 1.75rem;
    }

    .logo {
        width: 36px;
        height: 36px;
    }

    .tagline {
        font-size: 0.95rem;
    }

    .options-panel,
    .stats-panel {
        padding: 1rem;
    }

    .options-grid {
        grid-template-columns: 1fr;
    }

    .panel-header {
        padding: 0.75rem 1rem;
    }

    .panel-actions {
        width: 100%;
        justify-content: flex-end;
    }

    .btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.85rem;
    }

    .btn-primary {
        padding: 0.75rem 1.5rem;
        width: 100%;
        justify-content: center;
    }

    textarea {
        min-height: 150px;
        font-size: 0.85rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .stat-card {
        padding: 0.75rem;
    }

    .stat-value {
        font-size: 1.1rem;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.5rem;
    }

    .logo-section {
        gap: 0.5rem;
    }

    .panel-header h3 {
        font-size: 0.9rem;
    }

    .btn span:not(.checkbox-custom) {
        display: none;
    }

    .btn svg {
        margin: 0;
    }

    .panel-actions .btn {
        padding: 0.5rem;
    }
}

/* Animation for stats update */
@keyframes pulse {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
    100% {
        transform: scale(1);
    }
}

.stat-card.updated {
    animation: pulse 0.3s ease;
}

/* Focus styles for accessibility */
.btn:focus-visible,
.option:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

textarea:focus-visible {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--primary-color);
}

/* Scrollbar styling */
textarea::-webkit-scrollbar {
    width: 8px;
}

textarea::-webkit-scrollbar-track {
    background: var(--surface);
}

textarea::-webkit-scrollbar-thumb {
    background: var(--surface-light);
    border-radius: 4px;
}

textarea::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}