/* CSS Variables */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --success-color: #22c55e;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #475569;
    --border-radius: 12px;
    --border-radius-sm: 8px;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.4);
    --transition: all 0.3s ease;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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;
}

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header */
.header {
    text-align: center;
    padding: 2rem 1rem;
    background: linear-gradient(135deg, var(--surface) 0%, var(--background) 100%);
    border-bottom: 1px solid var(--border-color);
}

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

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

.header h1 {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, #ff6b6b, #4ecdc4, #45b7d1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Main Content */
.main-content {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
    width: 100%;
}

/* Sections */
.section {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
}

.section h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Tab Buttons */
.tab-buttons {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 0.5rem 1rem;
    background: var(--surface-light);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.875rem;
}

.tab-btn:hover {
    background: var(--border-color);
    color: var(--text-primary);
}

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

/* Tab Content */
.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Gradient Builder */
.gradient-builder {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.gradient-type-selector {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

.gradient-type-selector label {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.gradient-type-selector select {
    padding: 0.5rem;
    background: var(--surface-light);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    cursor: pointer;
}

/* Color Stops */
.color-stops-container {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.color-stops-container > label {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

#color-stops {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.color-stop {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem;
    background: var(--surface-light);
    border-radius: var(--border-radius-sm);
    flex-wrap: wrap;
}

.color-stop .color-picker {
    width: 50px;
    height: 36px;
    border: none;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    padding: 0;
}

.color-stop .stop-position {
    width: 60px;
    padding: 0.5rem;
    background: var(--surface);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    text-align: center;
}

.color-stop span {
    color: var(--text-secondary);
}

.remove-stop {
    width: 28px;
    height: 28px;
    background: var(--error-color);
    border: none;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    font-size: 1.25rem;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    margin-left: auto;
}

.remove-stop:hover {
    background: #dc2626;
    transform: scale(1.1);
}

/* CSS Input */
.css-input-container {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.css-input-container label {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.css-input-container textarea {
    width: 100%;
    min-height: 100px;
    padding: 1rem;
    background: var(--surface-light);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    font-family: 'Monaco', 'Menlo', monospace;
    font-size: 0.875rem;
    resize: vertical;
}

.css-input-container textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Presets Grid */
.presets-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 1rem;
}

.preset-item {
    height: 80px;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.preset-item:hover {
    transform: scale(1.05);
    border-color: var(--primary-color);
}

.preset-item::after {
    content: attr(data-name);
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 0.25rem;
    background: rgba(0, 0, 0, 0.7);
    color: white;
    font-size: 0.75rem;
    text-align: center;
}

/* Gradient Preview */
.gradient-preview-container {
    margin-top: 1.5rem;
}

.gradient-preview-container h3 {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.gradient-preview {
    height: 120px;
    border-radius: var(--border-radius);
    margin-bottom: 0.75rem;
    border: 1px solid var(--border-color);
}

.gradient-css-output {
    display: flex;
    gap: 0.5rem;
    align-items: center;
    background: var(--surface-light);
    padding: 0.75rem;
    border-radius: var(--border-radius-sm);
    overflow-x: auto;
}

.gradient-css-output code {
    flex: 1;
    font-family: 'Monaco', 'Menlo', monospace;
    font-size: 0.75rem;
    color: var(--text-secondary);
    white-space: nowrap;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
    font-size: 0.875rem;
}

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

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

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

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

.btn-small {
    padding: 0.4rem 0.75rem;
    font-size: 0.75rem;
}

.btn-large {
    width: 100%;
    padding: 1rem;
    font-size: 1rem;
    margin-top: 1rem;
}

/* Analysis Results */
.analysis-results {
    animation: fadeIn 0.5s ease;
}

.analysis-results.hidden {
    display: none;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Histogram */
.histogram-container {
    background: var(--surface-light);
    border-radius: var(--border-radius-sm);
    padding: 1rem;
    margin-bottom: 1rem;
}

#histogram-canvas {
    width: 100%;
    height: 200px;
}

.color-breakdown {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 0.75rem;
}

.color-breakdown-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem;
    background: var(--surface-light);
    border-radius: var(--border-radius-sm);
}

.color-swatch {
    width: 32px;
    height: 32px;
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--border-color);
}

.color-info {
    flex: 1;
}

.color-info .hex {
    font-family: monospace;
    font-size: 0.875rem;
}

.color-info .percentage {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* Dominant Colors */
.dominant-colors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
}

.dominant-color-card {
    background: var(--surface-light);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.dominant-color-preview {
    height: 80px;
}

.dominant-color-info {
    padding: 1rem;
}

.dominant-color-info h4 {
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
}

.color-values {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.color-values p {
    margin-bottom: 0.25rem;
    font-family: monospace;
}

/* Accessibility */
.accessibility-container {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.accessibility-card {
    background: var(--surface-light);
    border-radius: var(--border-radius);
    padding: 1rem;
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

.accessibility-color-pair {
    display: flex;
    gap: 0.25rem;
}

.accessibility-color {
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--border-color);
}

.accessibility-info {
    flex: 1;
    min-width: 200px;
}

.accessibility-info h4 {
    font-size: 0.875rem;
    margin-bottom: 0.25rem;
}

.contrast-ratio {
    font-size: 1.25rem;
    font-weight: 700;
}

.wcag-results {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-top: 0.5rem;
}

.wcag-badge {
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
}

.wcag-badge.pass {
    background: var(--success-color);
    color: white;
}

.wcag-badge.fail {
    background: var(--error-color);
    color: white;
}

/* Similar Gradients */
.similar-gradients-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
}

.similar-gradient-card {
    background: var(--surface-light);
    border-radius: var(--border-radius);
    overflow: hidden;
    cursor: pointer;
    transition: var(--transition);
}

.similar-gradient-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.similar-gradient-preview {
    height: 100px;
}

.similar-gradient-info {
    padding: 1rem;
}

.similar-gradient-info h4 {
    font-size: 0.875rem;
    margin-bottom: 0.25rem;
}

.similar-gradient-info p {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.use-gradient-btn {
    width: 100%;
    margin-top: 0.75rem;
    padding: 0.5rem;
    background: var(--primary-color);
    border: none;
    border-radius: var(--border-radius-sm);
    color: white;
    cursor: pointer;
    font-size: 0.75rem;
    font-weight: 600;
    transition: var(--transition);
}

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

/* Footer */
.footer {
    text-align: center;
    padding: 1.5rem;
    background: var(--surface);
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

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

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

/* Mobile Responsive */
@media (max-width: 768px) {
    .header h1 {
        font-size: 1.5rem;
    }

    .logo-container {
        flex-direction: column;
        gap: 0.5rem;
    }

    .section {
        padding: 1rem;
    }

    .gradient-type-selector {
        flex-direction: column;
        align-items: flex-start;
    }

    .color-stop {
        flex-wrap: wrap;
    }

    .presets-grid {
        grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    }

    .dominant-colors-grid {
        grid-template-columns: 1fr;
    }

    .similar-gradients-grid {
        grid-template-columns: 1fr;
    }

    .accessibility-card {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    html {
        font-size: 14px;
    }

    .tab-buttons {
        flex-direction: column;
    }

    .tab-btn {
        width: 100%;
        text-align: center;
    }

    .gradient-preview {
        height: 80px;
    }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

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

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

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