:root {
    --primary-color: #0f172a;
    --secondary-color: #1e293b;
    --accent-color: #0ea5e9;
    --success-color: #059669;
    --warning-color: #d97706;
    --danger-color: #dc2626;
    --light-color: #f8fafc;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
}

* {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--gray-50);
    color: var(--gray-800);
    line-height: 1.6;
}

.navbar {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    box-shadow: 0 4px 24px rgba(15, 23, 42, 0.08);
    padding: 1rem 0;
    backdrop-filter: blur(20px);
}

.navbar-brand {
    color: white !important;
    font-weight: 700;
    font-size: 1.5rem;
    letter-spacing: -0.025em;
}

.navbar-brand i {
    margin-right: 12px;
    color: var(--accent-color);
    font-size: 1.25rem;
}

.nav-link {
    color: rgba(255,255,255,0.85) !important;
    transition: all 0.2s ease;
    font-weight: 500;
    font-size: 0.9rem;
    padding: 0.5rem 1rem !important;
    margin: 0 0.25rem;
    border-radius: 6px;
}

.nav-link:hover {
    color: white !important;
    background-color: rgba(255, 255, 255, 0.1);
    transform: translateY(-1px);
}

.nav-link i {
    font-size: 0.85rem;
    opacity: 0.8;
}

.hero-section {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 50%, var(--accent-color) 100%);
    color: white;
    padding: 4rem 0;
    margin-bottom: 0;
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 1000"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="white" opacity="0.05"/></pattern></defs><rect width="100%" height="100%" fill="url(%23grain)"/></svg>');
    pointer-events: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-color) 0%, #0284c7 100%);
    border: none;
    color: white;
    font-weight: 600;
    padding: 12px 24px;
    border-radius: 8px;
    transition: all 0.2s ease;
    font-size: 0.9rem;
    letter-spacing: 0.025em;
    box-shadow: 0 4px 12px rgba(14, 165, 233, 0.25);
}

.btn-primary:hover {
    background: linear-gradient(135deg, #0284c7 0%, var(--accent-color) 100%);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(14, 165, 233, 0.35);
}

.btn-outline-primary {
    border: 2px solid var(--accent-color);
    color: #0284c7;
    font-weight: 600;
    padding: 10px 24px;
    border-radius: 8px;
    transition: all 0.2s ease;
    background: transparent;
}

.btn-outline-primary:hover,
.btn-outline-primary:focus-visible {
    background: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
    transform: translateY(-2px);
}

.btn-primary.btn-sm,
.btn-outline-primary.btn-sm {
    padding: 0.25rem 0.6rem;
    border-width: 1px;
    font-size: 0.85rem;
}

/* On dark sections, outline buttons are translucent white instead. */
.navbar .btn-outline-primary,
.hero-gradient .btn-outline-primary,
.page-header .btn-outline-primary,
.bg-primary .btn-outline-primary {
    border-color: rgba(255, 255, 255, 0.3);
    color: white;
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
}

.navbar .btn-outline-primary:hover,
.hero-gradient .btn-outline-primary:hover,
.page-header .btn-outline-primary:hover,
.bg-primary .btn-outline-primary:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.5);
}

.feature-card {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 24px rgba(15, 23, 42, 0.04);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid var(--gray-100);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-color) 0%, var(--success-color) 100%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 16px 48px rgba(15, 23, 42, 0.12);
}

.feature-card:hover::before {
    opacity: 1;
}

.score-badge {
    display: inline-flex;
    align-items: center;
    padding: 6px 12px;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.score-excellent { 
    background: linear-gradient(135deg, rgba(5, 150, 105, 0.1) 0%, rgba(5, 150, 105, 0.05) 100%); 
    color: var(--success-color); 
    border: 1px solid rgba(5, 150, 105, 0.2);
}
.score-good { 
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.1) 0%, rgba(14, 165, 233, 0.05) 100%); 
    color: var(--accent-color);
    border: 1px solid rgba(14, 165, 233, 0.2);
}
.score-average { 
    background: linear-gradient(135deg, rgba(217, 119, 6, 0.1) 0%, rgba(217, 119, 6, 0.05) 100%); 
    color: var(--warning-color);
    border: 1px solid rgba(217, 119, 6, 0.2);
}
.score-poor { 
    background: linear-gradient(135deg, rgba(220, 38, 38, 0.1) 0%, rgba(220, 38, 38, 0.05) 100%); 
    color: var(--danger-color);
    border: 1px solid rgba(220, 38, 38, 0.2);
}

footer {
    background: linear-gradient(135deg, var(--gray-900) 0%, var(--primary-color) 100%);
    color: var(--gray-300);
    padding: 4rem 0 2rem;
    margin-top: 6rem;
    border-top: 1px solid var(--gray-800);
}

footer h5 {
    color: white;
    font-weight: 600;
    margin-bottom: 1.5rem;
}

footer a {
    color: var(--gray-400);
    text-decoration: none;
    transition: color 0.2s ease;
}

footer a:hover {
    color: var(--accent-color);
}

.upload-zone {
    border: 2px dashed var(--gray-300);
    border-radius: 12px;
    padding: 3rem;
    text-align: center;
    background: linear-gradient(135deg, var(--gray-50) 0%, white 100%);
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
}

.upload-zone:hover {
    border-color: var(--accent-color);
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.02) 0%, rgba(14, 165, 233, 0.05) 100%);
}

.progress-bar {
    border-radius: 6px;
    height: 8px;
}

.section-title {
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 0.75rem;
    letter-spacing: -0.025em;
}

.section-subtitle {
    color: var(--gray-600);
    font-size: 1.1rem;
    line-height: 1.6;
}

.metric-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--gray-900);
    line-height: 1;
}

.metric-label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--gray-600);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}