/* Text Diff Comparison Styles */
:root {
    --primary-color: #2563eb;
    --secondary-color: #475569;
    --success-color: #059669;
    --danger-color: #dc2626;
    --warning-color: #d97706;
    --info-color: #0891b2;
    --background: #ffffff;
    --surface: #f8fafc;
    --text: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --shadow: rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
    --transition: all 0.3s ease;
    
    /* Diff colors */
    --diff-added: #dcfce7;
    --diff-added-text: #166534;
    --diff-deleted: #fef2f2;
    --diff-deleted-text: #991b1b;
    --diff-modified: #fef3c7;
    --diff-modified-text: #92400e;
    --diff-unchanged: #f8fafc;
    --diff-unchanged-text: #475569;
}

[data-theme="dark"] {
    --background: #0f172a;
    --surface: #1e293b;
    --text: #f1f5f9;
    --text-secondary: #94a3b8;
    --border: #334155;
    --shadow: rgba(0, 0, 0, 0.3);
    
    /* Dark mode diff colors */
    --diff-added: #14532d;
    --diff-added-text: #bbf7d0;
    --diff-deleted: #7f1d1d;
    --diff-deleted-text: #fca5a5;
    --diff-modified: #78350f;
    --diff-modified-text: #fcd34d;
    --diff-unchanged: #1e293b;
    --diff-unchanged-text: #94a3b8;
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
    background: var(--background);
    color: var(--text);
    line-height: 1.6;
    transition: var(--transition);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

h1 {
    text-align: center;
    color: var(--text);
    margin-bottom: 30px;
    font-size: 2.5em;
}

h2 {
    color: var(--text);
    margin-bottom: 20px;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
}

h3 {
    color: var(--text);
    margin-bottom: 15px;
    font-size: 1.3em;
}

/* Controls */
.controls {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    align-items: center;
    justify-content: center;
    margin-bottom: 30px;
    padding: 20px;
    background: var(--surface);
    border-radius: var(--border-radius);
    box-shadow: 0 2px 4px var(--shadow);
}

.control-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.control-group label {
    font-weight: 500;
    color: var(--text);
    white-space: nowrap;
}

.control-select {
    padding: 8px 12px;
    border: 2px solid var(--border);
    border-radius: var(--border-radius);
    background: var(--background);
    color: var(--text);
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
}

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

input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary-color);
    cursor: pointer;
}

/* Action Buttons */
.action-buttons {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
}

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

.btn.primary:hover {
    background: #1d4ed8;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

.btn.secondary {
    background: var(--surface);
    color: var(--text);
    border: 2px solid var(--border);
}

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

/* Input Section */
.input-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    margin-bottom: 30px;
}

.text-input-container {
    background: var(--surface);
    border-radius: var(--border-radius);
    box-shadow: 0 4px 6px var(--shadow);
    overflow: hidden;
}

.input-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    background: var(--background);
    border-bottom: 2px solid var(--border);
    flex-wrap: wrap;
    gap: 10px;
}

.input-header h3 {
    margin: 0;
    color: var(--primary-color);
}

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

.action-btn {
    padding: 6px 12px;
    border: 1px solid var(--border);
    background: var(--background);
    color: var(--text);
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 12px;
    transition: var(--transition);
}

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

.file-input {
    display: none;
}

.text-input {
    width: 100%;
    min-height: 300px;
    border: none;
    background: var(--background);
    color: var(--text);
    font-family: 'Courier New', monospace;
    font-size: 14px;
    padding: 20px;
    resize: vertical;
    outline: none;
    line-height: 1.5;
}

.input-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
    background: var(--surface);
    font-size: 12px;
    color: var(--text-secondary);
    border-top: 1px solid var(--border);
}

.input-info span:nth-child(even) {
    font-weight: 600;
    color: var(--primary-color);
    margin-right: 15px;
}

/* Results Section */
.results-section {
    background: var(--surface);
    border-radius: var(--border-radius);
    box-shadow: 0 4px 6px var(--shadow);
    margin-bottom: 30px;
    overflow: hidden;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    background: var(--background);
    border-bottom: 2px solid var(--border);
    flex-wrap: wrap;
    gap: 15px;
}

.results-header h3 {
    margin: 0;
    color: var(--primary-color);
}

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

/* Statistics */
.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 20px;
    padding: 20px;
    background: var(--background);
    border-bottom: 1px solid var(--border);
}

.stat-item {
    text-align: center;
}

.stat-label {
    display: block;
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: 5px;
}

.stat-value {
    display: block;
    font-size: 24px;
    font-weight: 700;
}

.stat-value.added {
    color: var(--diff-added-text);
}

.stat-value.deleted {
    color: var(--diff-deleted-text);
}

.stat-value.modified {
    color: var(--diff-modified-text);
}

.stat-value.unchanged {
    color: var(--diff-unchanged-text);
}

/* Legend */
.legend {
    display: flex;
    justify-content: center;
    gap: 30px;
    padding: 15px 20px;
    background: var(--background);
    border-bottom: 1px solid var(--border);
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
}

.legend-color {
    width: 16px;
    height: 16px;
    border-radius: 3px;
    border: 1px solid var(--border);
}

.legend-color.added {
    background: var(--diff-added);
}

.legend-color.deleted {
    background: var(--diff-deleted);
}

.legend-color.modified {
    background: var(--diff-modified);
}

.legend-color.unchanged {
    background: var(--diff-unchanged);
}

/* Diff Output */
.diff-output {
    padding: 20px;
    font-family: 'Courier New', monospace;
    font-size: 14px;
    line-height: 1.5;
    max-height: 600px;
    overflow: auto;
}

/* Side-by-side diff */
.diff-sidebyside {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.diff-panel {
    border: 2px solid var(--border);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.diff-panel-header {
    padding: 10px 15px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    font-weight: 600;
    text-align: center;
}

.diff-panel-content {
    max-height: 400px;
    overflow: auto;
}

/* Inline diff */
.diff-inline {
    border: 2px solid var(--border);
    border-radius: var(--border-radius);
    overflow: hidden;
}

/* Diff lines */
.diff-line {
    display: flex;
    align-items: stretch;
    border-bottom: 1px solid var(--border);
}

.diff-line:last-child {
    border-bottom: none;
}

.line-number {
    padding: 8px 12px;
    background: var(--surface);
    color: var(--text-secondary);
    border-right: 1px solid var(--border);
    min-width: 60px;
    text-align: right;
    font-size: 12px;
    user-select: none;
}

.line-content {
    flex: 1;
    padding: 8px 15px;
    white-space: pre;
    word-wrap: break-word;
}

/* Diff types */
.diff-line.added {
    background: var(--diff-added);
    color: var(--diff-added-text);
}

.diff-line.deleted {
    background: var(--diff-deleted);
    color: var(--diff-deleted-text);
}

.diff-line.modified {
    background: var(--diff-modified);
    color: var(--diff-modified-text);
}

.diff-line.unchanged {
    background: var(--diff-unchanged);
    color: var(--diff-unchanged-text);
}

/* Character-level highlighting */
.char-added {
    background: var(--success-color);
    color: white;
    padding: 2px 4px;
    border-radius: 3px;
}

.char-deleted {
    background: var(--danger-color);
    color: white;
    padding: 2px 4px;
    border-radius: 3px;
}

/* Instructions */
.instructions {
    background: var(--surface);
    padding: 30px;
    border-radius: var(--border-radius);
    margin-top: 30px;
    box-shadow: 0 4px 6px var(--shadow);
}

.instruction-tabs {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 20px;
}

.instruction-tab {
    background: var(--background);
    padding: 20px;
    border-radius: var(--border-radius);
    border: 2px solid var(--border);
}

.instruction-tab h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 18px;
}

.instruction-tab ol {
    padding-left: 20px;
    margin: 0;
}

.instruction-tab li {
    margin-bottom: 8px;
    line-height: 1.5;
    color: var(--text);
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    background: var(--surface);
    color: var(--text);
    font-size: 20px;
    cursor: pointer;
    box-shadow: 0 4px 12px var(--shadow);
    transition: var(--transition);
    z-index: 1000;
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 20px var(--shadow);
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }

    h1 {
        font-size: 2em;
    }

    .controls {
        flex-direction: column;
        align-items: stretch;
        gap: 15px;
    }

    .control-group {
        justify-content: space-between;
    }

    .action-buttons {
        flex-direction: column;
        align-items: stretch;
    }

    .input-section {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .input-header {
        flex-direction: column;
        align-items: stretch;
        gap: 10px;
    }

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

    .results-header {
        flex-direction: column;
        align-items: stretch;
    }

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

    .stats {
        grid-template-columns: repeat(2, 1fr);
    }

    .legend {
        flex-direction: column;
        gap: 15px;
        align-items: center;
    }

    .diff-sidebyside {
        grid-template-columns: 1fr;
    }

    .instruction-tabs {
        grid-template-columns: 1fr;
    }
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.mb-20 {
    margin-bottom: 20px;
}

/* Success Message */
.success-message {
    position: fixed;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--success-color);
    color: white;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 12px var(--shadow);
    z-index: 10000;
    animation: slideDown 0.3s ease-out;
}

@keyframes slideDown {
    from {
        transform: translateX(-50%) translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateX(-50%) translateY(0);
        opacity: 1;
    }
}

/* Loading State */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 40px;
    height: 40px;
    border: 4px solid var(--border);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: translate(-50%, -50%) rotate(0deg); }
    100% { transform: translate(-50%, -50%) rotate(360deg); }
}