/* css/main.css - Core styles and variables */

:root {
    /* Color Scheme - Drain: Infrastructure, Urban Resilience, Climate Action */
    
    /* Primary - Infrastructure Navy */
    --color-primary-900: #061220;
    --color-primary-800: #0C2238;
    --color-primary-700: #163A5C;
    --color-primary-600: #225276;
    --color-primary-500: #2E6A90;
    --color-primary-400: #4A8AB0;
    --color-primary-300: #78B0CC;
    --color-primary-200: #A8CCE3;
    --color-primary-100: #D4E8F2;
    --color-primary-50: #F0F5FA;
    
    /* Secondary - Flood Warning Orange */
    --color-secondary-900: #7A3318;
    --color-secondary-800: #A54A24;
    --color-secondary-700: #C45D30;
    --color-secondary-600: #E86A2C;
    --color-secondary-500: #F0804A;
    --color-secondary-400: #F4986A;
    --color-secondary-300: #F8B48A;
    --color-secondary-200: #FBD0B8;
    --color-secondary-100: #FDE8DB;
    --color-secondary-50: #FFF4ED;
    
    /* Accent - Water Teal */
    --color-accent-900: #0D4A40;
    --color-accent-800: #156B5E;
    --color-accent-700: #1D8C7C;
    --color-accent-600: #1A9B8A;
    --color-accent-500: #4CB8A8;
    --color-accent-400: #70CCBD;
    --color-accent-300: #94DDD1;
    --color-accent-200: #B8EDE5;
    --color-accent-100: #DCF6F2;
    --color-accent-50: #F0FBF9;
    
    /* Neutral Grayscale */
    --color-gray-900: #0D1117;
    --color-gray-800: #161B22;
    --color-gray-700: #1F242F;
    --color-gray-600: #30363D;
    --color-gray-500: #484F58;
    --color-gray-400: #6E7681;
    --color-gray-300: #8B949E;
    --color-gray-200: #B1BAC4;
    --color-gray-150: #D0D7DE;
    --color-gray-100: #E6EDF4;
    --color-gray-50: #F0F6FC;
    
    /* Semantic Colors */
    --color-success: #27AE60;
    --color-success-bg: #DAFBE1;
    --color-warning: #F4A261;
    --color-warning-bg: #FEF2D5;
    --color-error: #C44536;
    --color-error-bg: #FDE2E2;
    --color-info: #58A6FF;
    --color-info-bg: #E1F0FF;
    
    /* Background & Surface */
    --color-background: #FFFFFF;
    --color-background-alt: var(--color-gray-50);
    --color-surface: #FFFFFF;
    --color-surface-alt: var(--color-gray-50);
    --color-surface-hover: var(--color-gray-100);
    
    /* Text */
    --color-text-primary: var(--color-gray-900);
    --color-text-secondary: var(--color-gray-700);
    --color-text-tertiary: var(--color-gray-500);
    --color-text-inverse: #FFFFFF;
    --color-text-link: var(--color-primary-600);
    
    /* Borders */
    --color-border: var(--color-gray-200);
    --color-border-light: var(--color-gray-150);
    --color-border-dark: var(--color-gray-300);
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-display: 'Inter', 'Source Serif Pro', Georgia, serif;
    
    /* Font Sizes - Clamped for responsiveness */
    --text-5xl: clamp(3rem, 6vw, 4.5rem);
    --text-4xl: clamp(2.5rem, 5vw, 4rem);
    --text-3xl: clamp(2rem, 3.5vw, 3rem);
    --text-2xl: clamp(1.5rem, 2.5vw, 2rem);
    --text-xl: clamp(1.25rem, 1.8vw, 1.5rem);
    --text-lg: clamp(1.125rem, 1.2vw, 1.25rem);
    --text-base: clamp(1rem, 1vw, 1.125rem);
    --text-sm: clamp(0.875rem, 0.8vw, 0.95rem);
    --text-xs: clamp(0.75rem, 0.6vw, 0.85rem);
    
    /* Line Heights */
    --leading-none: 1;
    --leading-tight: 1.2;
    --leading-normal: 1.5;
    --leading-relaxed: 1.7;
    --leading-loose: 2;
    
    /* Font Weights */
    --weight-light: 300;
    --weight-regular: 400;
    --weight-medium: 500;
    --weight-semibold: 600;
    --weight-bold: 700;
    --weight-extrabold: 800;
    
    /* Spacing Scale */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;
    --space-32: 8rem;
    --space-40: 10rem;
    
    /* Containers */
    --container-sm: 640px;
    --container-md: 768px;
    --container-lg: 1024px;
    --container-xl: 1280px;
    --container-2xl: 1536px;
    
    /* Section Spacing */
    --section-padding: clamp(4rem, 8vw, 8rem);
    --section-padding-sm: clamp(3rem, 5vw, 4rem);
    
    /* Component Spacing */
    --component-gap: clamp(1.5rem, 3vw, 3rem);
    --component-padding: clamp(1.5rem, 2.5vw, 2.5rem);
    
    /* Border Radius */
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 16px;
    --border-radius-xl: 24px;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
    --shadow-xl: 0 16px 48px rgba(0,0,0,0.15);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

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

body {
    font-family: var(--font-primary);
    color: var(--color-text-primary);
    line-height: var(--leading-relaxed);
    background-color: var(--color-background);
}

.container {
    max-width: var(--container-xl);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: var(--weight-bold);
    line-height: var(--leading-tight);
    margin-bottom: var(--space-4);
    color: var(--color-text-primary);
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p {
    margin-bottom: var(--space-4);
    color: var(--color-text-secondary);
}

a {
    color: var(--color-primary-600);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-secondary-600);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius-md);
    font-weight: var(--weight-semibold);
    font-size: var(--text-base);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.btn-primary {
    background-color: var(--color-secondary-600);
    color: white;
    border-color: var(--color-secondary-600);
}

.btn-primary:hover {
    background-color: var(--color-secondary-700);
    border-color: var(--color-secondary-700);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    color: white;
}

.btn-secondary {
    background-color: transparent;
    border-color: var(--color-primary-600);
    color: var(--color-primary-600);
}

.btn-secondary:hover {
    background-color: var(--color-primary-600);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-outline {
    background-color: transparent;
    border-color: white;
    color: white;
}

.btn-outline:hover {
    background-color: white;
    color: var(--color-primary-800);
    transform: translateY(-2px);
}

.btn-large {
    padding: 1rem 2.5rem;
    font-size: var(--text-lg);
}

.btn-block {
    width: 100%;
}

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: var(--space-12);
}

.section-header.light {
    color: white;
}

.section-header.light .section-title {
    color: white;
}

.section-header.light .section-subtitle {
    color: rgba(255,255,255,0.9);
}

.section-title {
    font-size: var(--text-3xl);
    font-weight: var(--weight-bold);
    margin-bottom: var(--space-3);
    position: relative;
    display: inline-block;
    font-family: var(--font-display);
    letter-spacing: -0.02em;
}

.section-subtitle {
    font-size: var(--text-lg);
    color: var(--color-text-tertiary);
    margin-top: -var(--space-2);
    margin-bottom: var(--space-4);
}

.title-highlight {
    color: var(--color-secondary-600);
    position: relative;
    display: inline-block;
}

.title-underline {
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary-600), var(--color-secondary-600));
    margin: var(--space-3) auto 0;
    border-radius: 2px;
}

/* Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-5 { margin-top: var(--space-5); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mt-12 { margin-top: var(--space-12); }

.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-5 { margin-bottom: var(--space-5); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }
.mb-12 { margin-bottom: var(--space-12); }

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(40px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.6s ease forwards;
}

.slide-up {
    animation: slideUp 0.8s ease forwards;
}

/* Responsive */
@media (max-width: 820px) {
    .container {
        padding: 0 var(--space-4);
    }
    
    h1 { font-size: var(--text-3xl); }
    h2 { font-size: var(--text-2xl); }
    h3 { font-size: var(--text-xl); }
    
    .section-title {
        font-size: var(--text-2xl);
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-4);
    }
    
    h1 { font-size: var(--text-2xl); }
    h2 { font-size: var(--text-xl); }
    
    .section-title {
        font-size: var(--text-xl);
    }
}