/* ================================
   Design System - Variables
   ================================ */

:root {
    /* Colors - Slate Palette */
    --color-bg: #FAFAFA;
    --color-surface: #FFFFFF;
    --color-border: #E5E7EB;
    
    --color-text-primary: #0F172A;
    --color-text-secondary: #475569;
    --color-text-tertiary: #94A3B8;
    
    --color-accent: #475569;
    --color-accent-hover: #334155;
    
    /* Warm accents for hero image */
    --color-warm-1: #F59E0B;
    --color-warm-2: #EF4444;
    --color-warm-3: #EC4899;
    
    /* Typography */
    --font-family: 'Manrope', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    
    --font-size-xs: 0.875rem;    /* 14px */
    --font-size-sm: 1rem;         /* 16px */
    --font-size-md: 1.125rem;     /* 18px */
    --font-size-lg: 1.25rem;      /* 20px */
    --font-size-xl: 1.5rem;       /* 24px */
    --font-size-2xl: 2rem;        /* 32px */
    --font-size-3xl: 2.5rem;      /* 40px */
    --font-size-4xl: 3rem;        /* 48px */
    
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    /* Spacing */
    --space-xs: 0.5rem;      /* 8px */
    --space-sm: 1rem;        /* 16px */
    --space-md: 1.5rem;      /* 24px */
    --space-lg: 2rem;        /* 32px */
    --space-xl: 3rem;        /* 48px */
    --space-2xl: 4rem;       /* 64px */
    --space-3xl: 6rem;       /* 96px */
    
    /* Layout */
    --container-max: 1200px;
    --container-padding: 1.5rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;   /* 6px */
    --radius-md: 0.5rem;     /* 8px */
    --radius-lg: 0.75rem;    /* 12px */
    --radius-xl: 1rem;       /* 16px */
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
    --transition-slow: 500ms ease;
}

/* ================================
   Reset & Base Styles
   ================================ */

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-normal);
    line-height: 1.6;
    color: var(--color-text-primary);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
}

ul {
    list-style: none;
}

button {
    font-family: inherit;
    border: none;
    background: none;
    cursor: pointer;
}

/* ================================
   Typography
   ================================ */

h1, h2, h3, h4, h5, h6 {
    font-weight: var(--font-weight-semibold);
    line-height: 1.2;
    color: var(--color-text-primary);
}

h1 {
    font-size: var(--font-size-4xl);
}

h2 {
    font-size: var(--font-size-2xl);
}

h3 {
    font-size: var(--font-size-xl);
}

p {
    margin-bottom: var(--space-sm);
}

/* ================================
   Buttons
   ================================ */

.btn {
    display: inline-block;
    padding: 0.875rem 1.75rem;
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
    text-align: center;
}

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

.btn-primary:hover {
    background-color: var(--color-accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(15, 23, 42, 0.15);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-text-primary);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    transform: translateY(-2px);
}

.btn-text {
    padding: 0;
    color: var(--color-accent);
    font-weight: var(--font-weight-medium);
}

.btn-text:hover {
    color: var(--color-accent-hover);
}

/* ================================
   Navigation
   ================================ */

.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(250, 250, 250, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--color-border);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: var(--space-sm) var(--container-padding);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-text-primary);
    position: relative;
    z-index: 1002;
    cursor: pointer;
}

.nav-menu {
    display: flex;
    gap: var(--space-lg);
    align-items: center;
}

.nav-menu a {
    font-weight: var(--font-weight-medium);
    transition: color var(--transition-fast);
}

.nav-menu a:hover {
    color: var(--color-accent);
}

.nav-cta {
    padding: 0.5rem 1.25rem;
    background-color: var(--color-accent);
    color: white !important;
    border-radius: var(--radius-sm);
    transition: all var(--transition-normal);
}

.nav-cta:hover {
    background-color: var(--color-accent-hover);
    transform: translateY(-1px);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--space-xs);
    z-index: 1001;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--color-text-primary);
    transition: all var(--transition-fast);
    display: block;
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

/* ================================
   Hero Section
   ================================ */

.hero {
    padding: calc(var(--space-3xl) + 60px) var(--container-padding) var(--space-3xl);
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-container-centered {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.hero-image-small {
    margin: 0 auto var(--space-xl);
    width: 140px;
    height: 140px;
}

.hero-image-small img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
    border: 3px solid var(--color-border);
}

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--space-sm);
    line-height: 1.1;
}

.hero-role {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-md);
}

.hero-tagline {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-medium);
    color: var(--color-accent);
    margin-bottom: var(--space-md);
}

.hero-description {
    font-size: var(--font-size-md);
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-md);
}

.hero-location {
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
    margin-bottom: var(--space-xl);
    font-weight: var(--font-weight-medium);
}

.hero-cta {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
}


/* ================================
   Work Section
   ================================ */

.work {
    padding: var(--space-3xl) var(--container-padding);
    background-color: var(--color-surface);
}

.work-container {
    max-width: var(--container-max);
    margin: 0 auto;
}

.section-header {
    margin-bottom: var(--space-2xl);
}

.section-header h2 {
    margin-bottom: var(--space-md);
}

.filter-tabs {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.filter-tab {
    padding: 0.5rem 1rem;
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-secondary);
    background-color: transparent;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.filter-tab:hover,
.filter-tab.active {
    color: var(--color-accent);
    border-color: var(--color-accent);
    background-color: rgba(71, 85, 105, 0.05);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--space-xl);
}

.project-card {
    background: rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-normal);
    border: 1px solid rgba(229, 231, 235, 0.6);
    box-shadow: 0 8px 16px rgba(15, 23, 42, 0.04);
}

.project-card:hover {
    transform: translateY(-4px);
    background: rgba(255, 255, 255, 0.75);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    box-shadow: 0 16px 48px rgba(15, 23, 42, 0.1);
    border-color: rgba(71, 85, 105, 0.4);
}

.project-link {
    display: block;
}

.project-image {
    position: relative;
    aspect-ratio: 16 / 10;
    background-color: var(--color-bg);
    overflow: hidden;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.project-card:hover .project-image img {
    transform: scale(1.05);
}

.project-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(15, 23, 42, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.project-card:hover .project-overlay {
    opacity: 1;
}

.view-project {
    color: white;
    font-weight: var(--font-weight-semibold);
    font-size: var(--font-size-md);
}

.project-content {
    padding: var(--space-md);
}

.project-tags {
    display: flex;
    gap: var(--space-xs);
    margin-bottom: var(--space-sm);
    flex-wrap: wrap;
}

.tag {
    padding: 0.25rem 0.75rem;
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-medium);
    background-color: var(--color-bg);
    color: var(--color-text-secondary);
    border-radius: var(--radius-sm);
}

.project-title {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--space-xs);
    color: var(--color-text-primary);
}

.project-description {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: 1.6;
    margin-bottom: var(--space-sm);
}

.project-outcome {
    font-size: var(--font-size-xs);
    color: var(--color-text-tertiary);
    padding-top: var(--space-xs);
    border-top: 1px solid var(--color-border);
}

.project-outcome strong {
    color: var(--color-accent);
}

/* ================================
   Approach Section
   ================================ */

.approach {
    padding: var(--space-3xl) var(--container-padding);
    background-color: var(--color-bg);
}

.approach-container {
    max-width: var(--container-max);
    margin: 0 auto;
}

.section-title {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-semibold);
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.approach-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-xl);
}

.approach-card {
    text-align: center;
    padding: var(--space-lg);
}

.approach-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--space-md);
    color: var(--color-accent);
}

.approach-card h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--space-sm);
}

.approach-card p {
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* ================================
   About Preview Section
   ================================ */

.about-preview {
    padding: var(--space-3xl) var(--container-padding);
    background-color: var(--color-surface);
}

.about-preview-container {
    max-width: var(--container-max);
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
    align-items: center;
}

.about-preview-image img {
    width: 100%;
    max-width: 400px;
    border-radius: var(--radius-xl);
    box-shadow: 0 20px 60px rgba(15, 23, 42, 0.1);
}

.about-preview-content h2 {
    margin-bottom: var(--space-md);
}

.about-preview-content p {
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-md);
}

/* ================================
   Contact Section
   ================================ */

.contact {
    padding: var(--space-3xl) var(--container-padding);
    background-color: var(--color-bg);
    text-align: center;
}

.contact-container {
    max-width: 700px;
    margin: 0 auto;
}

.contact-subtitle {
    font-size: var(--font-size-md);
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-xl);
}

.contact-links {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
    flex-wrap: wrap;
}

/* ================================
   Footer
   ================================ */

.footer {
    padding: var(--space-2xl) var(--container-padding) var(--space-lg);
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
}

.footer-container {
    max-width: var(--container-max);
    margin: 0 auto;
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
}

.footer-links {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
}

.footer-brand {
    display: flex;
    justify-content: flex-start;
}

.footer-column h4 {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--space-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer-column ul li {
    margin-bottom: var(--space-xs);
}

.footer-column a {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    padding-top: var(--space-lg);
    border-top: 1px solid var(--color-border);
    text-align: center;
}

.footer-bottom p {
    color: var(--color-text-tertiary);
    font-size: var(--font-size-xs);
}

/* ================================
   Responsive Design
   ================================ */

@media (max-width: 768px) {
    :root {
        --font-size-4xl: 2.25rem;
        --font-size-3xl: 2rem;
        --font-size-2xl: 1.75rem;
    }
    
    .nav-menu {
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background-color: var(--color-surface);
        flex-direction: column;
        padding: var(--space-lg);
        border-bottom: 1px solid var(--color-border);
        transform: translateY(-100%);
        opacity: 0;
        transition: all var(--transition-normal);
        z-index: 1000;
        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
    }
    
    .nav-menu li {
        width: 100%;
        text-align: center;
    }
    
    .nav-menu a {
        display: block;
        padding: var(--space-sm) 0;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero {
        padding-top: calc(var(--space-2xl) + 60px);
        min-height: auto;
    }
    
    .hero-container-centered {
        max-width: 100%;
    }
    
    .hero-image-small {
        width: 120px;
        height: 120px;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .hero-cta .btn {
        width: 100%;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .approach-grid {
        grid-template-columns: 1fr;
    }
    
    .about-preview-container {
        grid-template-columns: 1fr;
        gap: var(--space-xl);
    }
    
    .about-preview-image {
        text-align: center;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
    }
    
    .contact-links {
        flex-direction: column;
        gap: var(--space-md);
    }
}

@media (max-width: 480px) {
    :root {
        --font-size-4xl: 2rem;
        --font-size-3xl: 1.75rem;
        --font-size-2xl: 1.5rem;
        --font-size-xl: 1.25rem;
    }
    
    .hero-title {
        font-size: var(--font-size-3xl);
    }
    
    .hero-role {
        font-size: var(--font-size-lg);
    }
    
    .hero-cta .btn {
        width: 100%;
    }
    
    .approach-card {
        padding: var(--space-md);
    }
    
    .project-filters {
        gap: var(--space-xs);
    }
    
    .filter-btn {
        padding: var(--space-xs) var(--space-sm);
        font-size: var(--font-size-sm);
    }
}

/* ================================
   Image Placeholders
   ================================ */

/* Graceful handling of missing images */
.hero-image-small img,
.project-image img,
.about-preview-image img {
    background: linear-gradient(135deg, 
        var(--color-bg) 0%, 
        var(--color-border) 50%, 
        var(--color-bg) 100%);
}

/* Hero image placeholder */

/* Project image placeholders */
.project-image {
    background: linear-gradient(135deg, #F8F9FA 0%, #E5E7EB 100%);
}

.project-image img {
    background: transparent;
}

/* ================================
   Utility Classes
   ================================ */

.hidden {
    display: none;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}