:root {
    --bg-color: #0D1B2A;
    --primary-color: #0984E3;
    --secondary-color: #74B9FF;
    --accent-color: #E17055;
    --text-color: #E0E1DD;
    --text-muted: #B2BEC3;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --border-radius: 12px;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    
    --diff-add-bg: rgba(46, 204, 113, 0.15);
    --diff-add-text: #2ecc71;
    --diff-add-border: rgba(46, 204, 113, 0.3);
    --diff-del-bg: rgba(231, 76, 60, 0.15);
    --diff-del-text: #e74c3c;
    --diff-del-border: rgba(231, 76, 60, 0.3);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-sans);
    line-height: 1.6;
    min-height: 100vh;
    padding: 2rem 1rem;
}

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

header {
    text-align: center;
    margin-bottom: 3rem;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.logo i {
    width: 32px;
    height: 32px;
    color: var(--primary-color);
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--text-color) 0%, var(--secondary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

/* Input Section */
.input-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.input-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

label {
    font-weight: 500;
    font-size: 0.9rem;
    color: var(--secondary-color);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

textarea {
    width: 100%;
    min-height: 300px;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 1rem;
    color: var(--text-color);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    resize: vertical;
    transition: border-color 0.2s, box-shadow 0.2s;
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(9, 132, 227, 0.2);
}

/* Controls */
.controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1.5rem;
}

.view-options {
    display: flex;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 8px;
    padding: 4px;
}

.btn-toggle {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.2s;
}

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

.btn-toggle:hover:not(.active) {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-color);
}

.action-buttons {
    display: flex;
    gap: 1rem;
}

.btn-primary, .btn-secondary {
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.2s;
    border: none;
}

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

.btn-primary:hover {
    background: #0873c4;
    transform: translateY(-1px);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-color);
}

.btn-secondary:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-1px);
}

.btn-secondary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-icon {
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: all 0.2s;
}

.btn-icon:hover {
    color: var(--accent-color);
    background: rgba(255, 255, 255, 0.05);
}

/* Results */
.results-section {
    transition: opacity 0.3s ease;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 1rem;
}

.stats {
    display: flex;
    gap: 1.5rem;
}

.stat-item {
    font-size: 0.85rem;
    font-weight: 600;
    padding: 2px 8px;
    border-radius: 4px;
}

.stat-item.additions {
    color: var(--diff-add-text);
    background: var(--diff-add-bg);
}

.stat-item.deletions {
    color: var(--diff-del-text);
    background: var(--diff-del-bg);
}

.diff-output {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    overflow-x: auto;
}

.hidden {
    display: none;
}

/* Diff Rendering */
.diff-row {
    display: flex;
    min-height: 1.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.03);
}

.line-number {
    width: 40px;
    color: var(--text-muted);
    font-size: 0.75rem;
    text-align: right;
    padding-right: 10px;
    user-select: none;
    background: rgba(0, 0, 0, 0.1);
}

.line-content {
    flex: 1;
    padding-left: 10px;
    white-space: pre-wrap;
    word-break: break-all;
}

.diff-added {
    background-color: var(--diff-add-bg);
    color: var(--diff-add-text);
}

.diff-removed {
    background-color: var(--diff-del-bg);
    color: var(--diff-del-text);
}

.diff-added .line-content::before {
    content: "+";
    margin-right: 5px;
}

.diff-removed .line-content::before {
    content: "-";
    margin-right: 5px;
}

/* Side by Side specific */
.side-by-side {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2px;
    background: var(--glass-border);
}

.side-by-side .pane {
    background: var(--bg-color);
}

.side-by-side .diff-row {
    display: flex;
}

/* Footer */
footer {
    text-align: center;
    margin-top: 3rem;
    color: var(--text-muted);
    font-size: 0.85rem;
}

@media (max-width: 768px) {
    .input-section {
        grid-template-columns: 1fr;
    }
    
    .controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .view-options {
        justify-content: center;
    }
    
    .action-buttons {
        justify-content: center;
    }
    
    .side-by-side {
        grid-template-columns: 1fr;
    }
}