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

:root {
    --primary-color: #0066FF;
    --primary-hover: #0052CC;
    --secondary-color: #6B7280;
    --success-color: #10B981;
    --danger-color: #EF4444;
    --background: #FFFFFF;
    --surface: #F9FAFB;
    --border: #E5E7EB;
    --text-primary: #111827;
    --text-secondary: #6B7280;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --radius-lg: 12px;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: var(--background);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.95);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.logo svg {
    color: var(--primary-color);
}

.nav {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.lang-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.875rem;
    font-weight: 500;
}

.lang-btn:hover {
    background: var(--border);
    transform: translateY(-1px);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667EEA 0%, #764BA2 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    animation: fadeInUp 0.6s ease;
}

.hero p {
    font-size: 1.125rem;
    opacity: 0.95;
    animation: fadeInUp 0.6s ease 0.2s both;
}

/* Controls Section */
.controls {
    background: var(--surface);
    padding: 2rem 0;
    border-bottom: 1px solid var(--border);
}

.controls .container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.control-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.control-group select,
.control-group input[type="text"] {
    padding: 0.625rem 0.875rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 0.875rem;
    background: var(--background);
    transition: all 0.2s;
}

.control-group select:focus,
.control-group input[type="text"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

.control-group input[type="range"] {
    width: 100%;
    margin-top: 0.5rem;
}

.control-group input[type="color"] {
    width: 100%;
    height: 40px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
}

#fontSizeValue {
    font-weight: 600;
    color: var(--primary-color);
}

/* Weight Grid */
.weight-grid {
    padding: 3rem 0;
}

.weight-grid h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.weight-display {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.weight-card {
    background: var(--background);
    border: 2px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    cursor: pointer;
    transition: all 0.3s;
    position: relative;
    overflow: hidden;
}

.weight-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), #764BA2);
    transform: scaleX(0);
    transition: transform 0.3s;
}

.weight-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.weight-card.selected {
    border-color: var(--primary-color);
    background: linear-gradient(135deg, rgba(0, 102, 255, 0.05), rgba(118, 75, 162, 0.05));
}

.weight-card.selected::before {
    transform: scaleX(1);
}

.weight-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border);
}

.weight-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.weight-name {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.weight-preview {
    font-size: 1.125rem;
    line-height: 1.8;
    word-break: break-word;
    min-height: 60px;
}

/* Suggestions */
.suggestions {
    background: var(--surface);
    padding: 3rem 0;
}

.suggestions h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.suggestion-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.suggestion-card {
    background: var(--background);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    transition: all 0.3s;
}

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

.suggestion-card h4 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.preview-combo {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 1rem;
    margin-bottom: 1rem;
}

.preview-combo p {
    margin: 0.5rem 0;
    font-size: 1rem;
}

.apply-btn {
    width: 100%;
    padding: 0.625rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

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

/* CSS Generator */
.css-generator {
    padding: 3rem 0;
}

.css-generator h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.css-output {
    position: relative;
    background: #1F2937;
    border-radius: var(--radius-lg);
    padding: 1.5rem;
}

.css-output pre {
    color: #F3F4F6;
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
    line-height: 1.6;
    overflow-x: auto;
    margin: 0;
}

.copy-btn {
    position: absolute;
    top: 1rem;
    right: 1rem;
    padding: 0.5rem 1rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

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

.copy-btn.copied {
    background: var(--success-color);
}

/* Comparison */
.comparison {
    background: var(--surface);
    padding: 3rem 0;
}

.comparison h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.comparison-panel {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.compare-item {
    background: var(--background);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
}

.compare-item label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.compare-item select {
    width: 100%;
    padding: 0.625rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 1rem;
    font-size: 0.875rem;
}

.compare-preview {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 1.5rem;
    min-height: 100px;
    font-size: 1.125rem;
    line-height: 1.8;
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 2rem 0;
    text-align: center;
    margin-top: 4rem;
}

.footer p {
    font-size: 0.875rem;
    opacity: 0.8;
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero h2 {
        font-size: 1.875rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .controls .container {
        grid-template-columns: 1fr;
    }
    
    .weight-display {
        grid-template-columns: 1fr;
    }
    
    .suggestion-cards {
        grid-template-columns: 1fr;
    }
    
    .comparison-panel {
        grid-template-columns: 1fr;
    }
    
    .css-output pre {
        font-size: 0.75rem;
    }
    
    .copy-btn {
        position: static;
        width: 100%;
        margin-top: 1rem;
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --background: #0F172A;
        --surface: #1E293B;
        --border: #334155;
        --text-primary: #F1F5F9;
        --text-secondary: #94A3B8;
    }
    
    .header {
        background: rgba(15, 23, 42, 0.95);
    }
    
    .weight-card {
        background: var(--surface);
    }
    
    .suggestion-card {
        background: var(--surface);
    }
    
    .compare-item {
        background: var(--surface);
    }
}

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

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

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

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