/* Commit 3: Mobile-First Visual Design + Components + Motion & Polish */

/* CSS Variables for Theme Tokens */
:root {
    /* Light Mode Colors */
    --color-bg: #ffffff;
    --color-bg-secondary: #f8f9fa;
    --color-bg-tertiary: #f0f0f0;
    --color-text: #1a1a1a;
    --color-text-secondary: #4a4a4a;
    --color-text-tertiary: #6a6a6a;
    --color-border: #e0e0e0;
    --color-border-light: #f0f0f0;
    --color-accent: #2563eb;
    --color-accent-hover: #1d4ed8;
    --color-card-bg: #ffffff;
    --color-card-border: #e0e0e0;
    --color-card-shadow: rgba(0, 0, 0, 0.05);
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
    --font-size-sm: clamp(0.875rem, 0.825rem + 0.25vw, 1rem);
    --font-size-lg: clamp(1.125rem, 1.075rem + 0.25vw, 1.25rem);
    --font-size-xl: clamp(1.25rem, 1.15rem + 0.5vw, 1.5rem);
    --font-size-2xl: clamp(1.5rem, 1.35rem + 0.75vw, 2rem);
    --font-size-3xl: clamp(2rem, 1.7rem + 1.5vw, 3rem);
    --font-size-4xl: clamp(2.5rem, 2rem + 2.5vw, 4rem);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    
    /* Transitions */
    --transition-base: 150ms ease-in-out;
    --transition-fast: 100ms ease-in-out;
    
    /* Header */
    --header-height: 4rem;
    --header-bg: rgba(255, 255, 255, 0.9);
    --header-bg-blur: blur(12px);
    --header-border: rgba(224, 224, 224, 0.5);
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --color-bg: #0f0f0f;
        --color-bg-secondary: #1a1a1a;
        --color-bg-tertiary: #252525;
        --color-text: #f5f5f5;
        --color-text-secondary: #d0d0d0;
        --color-text-tertiary: #a0a0a0;
        --color-border: #333333;
        --color-border-light: #2a2a2a;
        --color-accent: #3b82f6;
        --color-accent-hover: #60a5fa;
        --color-card-bg: #1a1a1a;
        --color-card-border: #333333;
        --color-card-shadow: rgba(0, 0, 0, 0.3);
        --header-bg: rgba(15, 15, 15, 0.9);
        --header-border: rgba(51, 51, 51, 0.5);
    }
}

[data-theme="dark"] {
    --color-bg: #0f0f0f;
    --color-bg-secondary: #1a1a1a;
    --color-bg-tertiary: #252525;
    --color-text: #f5f5f5;
    --color-text-secondary: #d0d0d0;
    --color-text-tertiary: #a0a0a0;
    --color-border: #333333;
    --color-border-light: #2a2a2a;
    --color-accent: #3b82f6;
    --color-accent-hover: #60a5fa;
    --color-card-bg: #1a1a1a;
    --color-card-border: #333333;
    --color-card-shadow: rgba(0, 0, 0, 0.3);
    --header-bg: rgba(15, 15, 15, 0.9);
    --header-border: rgba(51, 51, 51, 0.5);
}

[data-theme="light"] {
    --color-bg: #ffffff;
    --color-bg-secondary: #f8f9fa;
    --color-bg-tertiary: #f0f0f0;
    --color-text: #1a1a1a;
    --color-text-secondary: #4a4a4a;
    --color-text-tertiary: #6a6a6a;
    --color-border: #e0e0e0;
    --color-border-light: #f0f0f0;
    --color-accent: #2563eb;
    --color-accent-hover: #1d4ed8;
    --color-card-bg: #ffffff;
    --color-card-border: #e0e0e0;
    --color-card-shadow: rgba(0, 0, 0, 0.05);
    --header-bg: rgba(255, 255, 255, 0.9);
    --header-border: rgba(224, 224, 224, 0.5);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    transition: background-color var(--transition-base), color var(--transition-base);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Header */
.site-header {
    position: sticky;
    top: 0;
    background: var(--header-bg);
    backdrop-filter: var(--header-bg-blur);
    -webkit-backdrop-filter: var(--header-bg-blur);
    border-bottom: 1px solid var(--header-border);
    z-index: 1000;
    transition: background-color var(--transition-base), border-color var(--transition-base);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    min-height: var(--header-height);
}

.logo {
    font-weight: 700;
    font-size: var(--font-size-xl);
    text-decoration: none;
    color: var(--color-text);
    transition: color var(--transition-base);
}

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

.header-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.theme-toggle {
    background: none;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm) var(--spacing-md);
    cursor: pointer;
    font-size: var(--font-size-lg);
    line-height: 1;
    color: var(--color-text);
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
}

.theme-toggle:hover {
    background: var(--color-bg-secondary);
    border-color: var(--color-accent);
}

.theme-toggle:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.theme-icon {
    display: block;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    padding: var(--spacing-sm);
    gap: 4px;
    width: 2.5rem;
    height: 2.5rem;
    justify-content: center;
    transition: all var(--transition-base);
}

.mobile-menu-toggle:hover {
    background: var(--color-bg-secondary);
    border-color: var(--color-accent);
}

.mobile-menu-toggle:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.mobile-menu-toggle span {
    width: 20px;
    height: 2px;
    background: var(--color-text);
    transition: all var(--transition-base);
    border-radius: 2px;
}

.main-nav ul {
    display: flex;
    list-style: none;
    gap: var(--spacing-xl);
}

.main-nav a {
    text-decoration: none;
    color: var(--color-text-secondary);
    font-weight: 500;
    transition: color var(--transition-base);
    position: relative;
}

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

.main-nav a:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 4px;
    border-radius: var(--radius-sm);
}

/* Sections */
section {
    padding: var(--spacing-3xl) 0;
}

h1 {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

h2 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--spacing-xl);
    color: var(--color-text);
}

h3 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

h4 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: var(--spacing-sm);
    margin-top: var(--spacing-lg);
    color: var(--color-text);
}

p {
    margin-bottom: var(--spacing-md);
    color: var(--color-text-secondary);
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-base);
}

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

a:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

/* Hero */
.hero {
    text-align: center;
    padding: var(--spacing-3xl) 0;
    background: linear-gradient(to bottom, var(--color-bg), var(--color-bg-secondary));
}

.hero-subhead {
    font-size: var(--font-size-xl);
    font-weight: 500;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.hero-support {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xl);
    color: var(--color-text-secondary);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.hero-ctas {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-xl);
}

.btn {
    display: inline-block;
    padding: var(--spacing-md) var(--spacing-xl);
    text-decoration: none;
    border-radius: var(--radius-md);
    border: 2px solid var(--color-accent);
    background: var(--color-accent);
    color: #ffffff;
    font-weight: 500;
    font-size: var(--font-size-base);
    transition: all var(--transition-base);
    cursor: pointer;
}

.btn:hover {
    background: var(--color-accent-hover);
    border-color: var(--color-accent-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn:focus-visible {
    outline: 3px solid var(--color-accent);
    outline-offset: 2px;
}

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

.btn-secondary:hover {
    background: var(--color-accent);
    color: #ffffff;
}

.btn-outline {
    background: transparent;
    color: var(--color-text);
    border-color: var(--color-border);
}

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

.trust-indicators {
    display: flex;
    gap: var(--spacing-xl);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-lg);
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
}

.trust-indicators span {
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
}

.availability-badge {
    margin-top: var(--spacing-xl);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    display: inline-block;
}

.availability-badge p {
    margin: 0;
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

/* What I Do */
.what-i-do {
    background: var(--color-bg-secondary);
}

.capabilities-list {
    list-style: none;
    max-width: 800px;
    margin: 0 auto;
}

.capabilities-list li {
    padding: var(--spacing-md) 0;
    padding-left: var(--spacing-xl);
    position: relative;
    color: var(--color-text-secondary);
    font-size: var(--font-size-lg);
}

.capabilities-list li::before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--color-accent);
    font-weight: 600;
}

/* About */
.about-content {
    max-width: 800px;
}

.about-content p {
    margin-bottom: var(--spacing-lg);
    font-size: var(--font-size-lg);
    line-height: 1.7;
}

.about-links {
    margin-top: var(--spacing-xl);
}

.about-links a {
    color: var(--color-accent);
    text-decoration: underline;
    text-underline-offset: 3px;
}

/* Strengths */
.strengths {
    background: var(--color-bg-secondary);
}

.strengths-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

.strength-card {
    padding: var(--spacing-xl);
    background: var(--color-card-bg);
    border: 1px solid var(--color-card-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

.strength-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--color-accent);
}

.strength-card h3 {
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.strength-card p {
    color: var(--color-text-secondary);
    margin: 0;
}

/* Case Studies */
.case-studies-disclaimer {
    background: var(--color-bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-xl);
    border-left: 4px solid var(--color-accent);
}

.case-studies-disclaimer p {
    margin: 0;
    color: var(--color-text-secondary);
}

.case-study {
    margin-bottom: var(--spacing-3xl);
    padding-bottom: var(--spacing-xl);
    border-bottom: 1px solid var(--color-border);
}

.case-study:last-child {
    border-bottom: none;
}

.case-study-content {
    max-width: 900px;
}

.case-study-content p {
    color: var(--color-text-secondary);
    line-height: 1.7;
}

.case-study-content ul {
    margin-left: var(--spacing-xl);
    margin-top: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.case-study-content li {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
}

/* Portfolio */
.portfolio {
    background: var(--color-bg-secondary);
}

.portfolio-disclaimer {
    background: var(--color-bg);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-xl);
    border-left: 4px solid var(--color-accent);
}

.portfolio-disclaimer p {
    margin: 0;
    color: var(--color-text-secondary);
}

.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-3xl);
}

.portfolio-card {
    background: var(--color-card-bg);
    border: 1px solid var(--color-card-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

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

.portfolio-image {
    width: 100%;
    background: var(--color-bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.portfolio-image img {
    width: 100%;
    height: auto;
    aspect-ratio: 16 / 9;
    object-fit: cover;
    transition: transform var(--transition-base);
}

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

.portfolio-content {
    padding: var(--spacing-xl);
}

.portfolio-category {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-sm);
    font-weight: 500;
    margin-bottom: var(--spacing-md);
    color: var(--color-accent);
}

.portfolio-content h3 {
    margin-bottom: var(--spacing-md);
}

.portfolio-content ul {
    margin-left: var(--spacing-xl);
    margin-top: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.portfolio-content li {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
}

.portfolio-tools {
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border-light);
}

.portfolio-note {
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
    margin-top: var(--spacing-sm);
    font-style: italic;
}

.portfolio-suggestions {
    margin-top: var(--spacing-3xl);
    padding: var(--spacing-xl);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
}

.portfolio-suggestions h3 {
    margin-bottom: var(--spacing-md);
}

.portfolio-suggestions ul {
    margin-left: var(--spacing-xl);
    margin-top: var(--spacing-md);
}

.portfolio-suggestions li {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
}

/* Experience */
.experience-list {
    max-width: 800px;
}

.experience-item {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-xl);
    border-bottom: 1px solid var(--color-border);
}

.experience-item:last-child {
    border-bottom: none;
}

.experience-role {
    font-weight: 600;
    margin-top: var(--spacing-sm);
    color: var(--color-text);
}

.experience-dates {
    color: var(--color-text-tertiary);
    font-size: var(--font-size-sm);
    margin-top: var(--spacing-xs);
}

.experience-description {
    margin-top: var(--spacing-md);
    color: var(--color-text-secondary);
}

/* Skills */
.skills-list {
    max-width: 600px;
    margin-left: var(--spacing-xl);
}

.skills-list li {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-secondary);
}

/* Education */
.education-item {
    max-width: 600px;
}

.education-item h3 {
    margin-bottom: var(--spacing-sm);
}

.education-item p {
    color: var(--color-text-secondary);
}

/* Contact */
.contact {
    background: var(--color-bg-secondary);
}

.contact-headline {
    font-size: var(--font-size-xl);
    font-weight: 500;
    margin-bottom: var(--spacing-xl);
    text-align: center;
    color: var(--color-text);
}

.contact-methods {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.contact-methods p {
    margin-bottom: var(--spacing-sm);
}

.contact-methods a {
    color: var(--color-accent);
    text-decoration: underline;
    text-underline-offset: 3px;
    font-size: var(--font-size-lg);
}

.contact-form {
    max-width: 600px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--color-text);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: var(--font-size-base);
    background: var(--color-bg);
    color: var(--color-text);
    transition: all var(--transition-base);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* Form Messages */
.form-message {
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    border-radius: var(--radius-md);
    font-weight: 500;
}

.form-message-success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.form-message-error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

/* Disable submit button when sending */
.contact-form button[type="submit"]:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Footer */
.site-footer {
    background: var(--color-bg-tertiary);
    padding: var(--spacing-xl) 0;
    text-align: center;
    margin-top: var(--spacing-3xl);
    border-top: 1px solid var(--color-border);
}

.site-footer p {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

.site-footer a {
    color: var(--color-accent);
    text-decoration: underline;
    text-underline-offset: 3px;
}

/* Mobile Menu */
@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }
    
    .main-nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--header-bg);
        backdrop-filter: var(--header-bg-blur);
        -webkit-backdrop-filter: var(--header-bg-blur);
        border-bottom: 1px solid var(--header-border);
        box-shadow: var(--shadow-lg);
    }
    
    .main-nav.active {
        display: block;
    }
    
    .main-nav ul {
        flex-direction: column;
        padding: var(--spacing-md);
        gap: 0;
    }
    
    .main-nav li {
        padding: var(--spacing-md) 0;
        border-bottom: 1px solid var(--color-border-light);
    }
    
    .main-nav li:last-child {
        border-bottom: none;
    }
    
    .main-nav a {
        display: block;
        padding: var(--spacing-sm) 0;
    }
    
    .hero {
        padding: var(--spacing-2xl) 0;
    }
    
    .hero-ctas {
        flex-direction: column;
        align-items: stretch;
    }
    
    .btn {
        text-align: center;
        width: 100%;
    }
    
    .strengths-grid,
    .portfolio-grid {
        grid-template-columns: 1fr;
    }
    
    .trust-indicators {
        gap: var(--spacing-md);
    }
    
    section {
        padding: var(--spacing-2xl) 0;
    }
}

/* Reveal Animations */
.reveal-on-scroll {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.reveal-on-scroll.revealed {
    opacity: 1;
    transform: translateY(0);
}

/* Back-to-top Button */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    background: var(--color-accent);
    color: #ffffff;
    border: none;
    cursor: pointer;
    font-size: var(--font-size-xl);
    font-weight: 600;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: opacity var(--transition-base), visibility var(--transition-base), transform var(--transition-base), background var(--transition-base);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--color-accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.back-to-top:focus-visible {
    outline: 3px solid var(--color-accent);
    outline-offset: 2px;
}

.back-to-top span {
    display: block;
}


/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    
    .reveal-on-scroll {
        opacity: 1;
        transform: none;
    }
    
    .back-to-top {
        transition: opacity var(--transition-fast), visibility var(--transition-fast);
    }
}