/*
 * ---------------------------------------
 * 1. Global Reset and Variables (Theming) - UPDATED 2025 AESTHETICS
 * ---------------------------------------
 */
:root {
    /* Colors (Dark Mode Aesthetic) */
    --color-background: #0d1117; 
    --color-surface: #1e2129; /* Slightly lighter surface for contrast */
    --color-text-primary: #f0f6fc;
    --color-text-secondary: #8b949e;
    --color-accent: #58a6ff; 
    --color-accent-dark: #3069a1;
    --color-border: #353b47;

    /* NEW AESTHETIC VARIABLES */
    --radius-sm: 6px;
    --radius-md: 12px;
    --shadow-soft: 0 4px 15px rgba(0, 0, 0, 0.4); /* Soft, diffused shadow */
    --shadow-hover: 0 8px 25px rgba(0, 0, 0, 0.6); /* Deeper shadow on hover */

    /* Typography */
    --font-primary: 'Inter', sans-serif;
    --font-mono: 'Roboto Mono', monospace;
    --font-size-base: 1.125rem;
    
    /* Spacing */
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 2rem;
    --space-xl: 4rem;
    
    /* Transitions */
    --transition-speed: 0.3s;
}

/* Light Mode Variables (Advanced Feature, controlled by JavaScript) */
body.light-mode {
    --color-background: #ffffff;
    --color-surface: #f0f0f0;
    --color-text-primary: #24292f;
    --color-text-secondary: #656d76;
    --color-accent: #0585f2;
    --color-accent-dark: #0056b3;
    --color-border: #d0d7de;
    --shadow-soft: 0 4px 15px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 8px 25px rgba(0, 0, 0, 0.2);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    line-height: 1.6;
    background-color: var(--color-background);
    color: var(--color-text-primary);
    min-height: 100vh;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

/* Skip Link for Accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-accent);
    color: var(--color-background);
    padding: var(--space-md);
    z-index: 999;
}
.skip-link:focus {
    top: 0;
}

/* --- SCROLL PROGRESS BAR --- */
#progress-bar-container {
    height: 4px;
    width: 100%;
    background-color: var(--color-surface);
    position: fixed;
    top: 0;
    left: 0;
    z-index: 101;
}

#progress-bar {
    height: 100%;
    width: 0%;
    background-color: var(--color-accent);
    transition: width 0.1s linear;
}

/* * ---------------------------------------
 * 2. Typography and Section Headers - UPDATED
 * ---------------------------------------
 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.section-padding {
    padding: var(--space-xl) 0;
}

h1, h2, h3 {
    line-height: 1.2;
    font-weight: 700;
    color: var(--color-text-primary);
}

h1 { font-size: 4rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 1.5rem; }

.section-title {
    margin-bottom: var(--space-lg);
    border-left: 5px solid var(--color-accent);
    padding-left: var(--space-md);
    display: inline-block;
    font-weight: 800;
}

/* Styling for keywords that were previously wrapped in ** */
.main-headline strong {
    color: var(--color-accent);
    font-weight: inherit;
}

/* * ---------------------------------------
 * 3. Header and Navigation - UPDATED
 * ---------------------------------------
 */
.site-header {
    background-color: var(--color-surface);
    padding: var(--space-md) 0;
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--color-text-primary);
    text-decoration: none;
}

nav a {
    color: var(--color-text-secondary);
    text-decoration: none;
    margin-left: var(--space-lg);
    padding: 0.5rem 0;
    transition: color var(--transition-speed);
    position: relative;
}

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

nav a:hover::after, nav a.active::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -5px;
    width: 100%;
    height: 3px;
    background-color: var(--color-accent);
    transform: scaleX(1);
}

nav a i {
    margin-right: 5px;
    color: var(--color-accent-dark);
}

.theme-toggle-btn {
    background: none;
    border: none;
    color: var(--color-text-primary);
    font-size: 1.25rem;
    cursor: pointer;
    margin-left: var(--space-lg);
    transition: color var(--transition-speed);
}
.theme-toggle-btn:hover {
    color: var(--color-accent);
}

/* * ---------------------------------------
 * 4. Buttons and Links - UPDATED ROUNDED EDGES & MICRO-INTERACTIONS
 * ---------------------------------------
 */
.btn {
    display: inline-flex;
    align-items: center;
    padding: 0.75rem 1.5rem;
    border: 2px solid transparent;
    border-radius: var(--radius-sm); /* Rounded edges */
    cursor: pointer;
    text-decoration: none;
    font-weight: 700;
    transition: all var(--transition-speed);
    font-size: 0.95rem; 
}

.primary-btn {
    background-color: var(--color-accent);
    color: var(--color-background);
    box-shadow: 0 4px 10px rgba(88, 166, 255, 0.3); /* Subtle accent shadow */
}

.primary-btn:hover {
    background-color: transparent;
    color: var(--color-accent);
    border-color: var(--color-accent);
    transform: scale(1.03); /* Micro-interaction: Scale up */
}

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

.secondary-btn:hover {
    background-color: var(--color-accent-dark);
    color: var(--color-text-primary);
    transform: translateY(-2px);
}

.large-btn {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.secondary-link {
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 500;
}

.secondary-link:hover {
    text-decoration: underline;
}

.text-center {
    text-align: center;
}

/* * ---------------------------------------
 * 5. Hero Section - UPDATED
 * ---------------------------------------
 */
.hero {
    padding: 6rem 0;
    text-align: center;
}

.role-tag {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--color-accent);
    margin-bottom: var(--space-sm);
    font-family: var(--font-mono);
}

.main-headline {
    margin-bottom: var(--space-md);
    letter-spacing: -1px;
}

.hero-summary {
    max-width: 900px;
    margin: 0 auto var(--space-lg) auto;
    font-size: 1.35rem;
    color: var(--color-text-secondary);
}

.hero-cta {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
    margin-top: var(--space-lg);
    align-items: center;
}

/* Tool ticker as modern rounded badges */
.tool-ticker {
    margin-top: var(--space-xl);
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    font-family: var(--font-mono);
    font-size: 0.9rem;
    color: var(--color-text-primary);
}
.tool-ticker span {
    background-color: var(--color-surface);
    padding: 8px 16px;
    border-radius: var(--radius-md); /* Rounded badges */
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-soft);
}

/* * ---------------------------------------
 * 6. Featured Projects (Grid Layout) - UPDATED ROUNDED EDGES & SHADOWS
 * ---------------------------------------
 */
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-lg);
}

.project-card {
    background-color: var(--color-surface);
    border-radius: var(--radius-md); /* Softer corners */
    box-shadow: var(--shadow-soft); /* Soft shadow */
    border: 1px solid transparent; /* Prepare for focus border */
    overflow: hidden;
    transition: transform var(--transition-speed), box-shadow var(--transition-speed), border-color var(--transition-speed);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover); /* Deeper shadow on hover */
    border-color: var(--color-accent-dark); /* Highlight border on hover */
}

.project-card:focus-within { /* Accessibility: Focus state */
    border-color: var(--color-accent);
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
    box-shadow: var(--shadow-hover);
}

.project-media-placeholder {
    height: 180px;
    background-color: var(--color-accent-dark);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-background);
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 700;
    /* Removed bottom border, using padding separation */
}

.card-content {
    padding: var(--space-lg);
}

.project-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--space-sm);
}

.project-card p {
    color: var(--color-text-secondary);
    margin-bottom: var(--space-md);
}

.project-tags {
    margin-bottom: var(--space-md);
}

.tag {
    display: inline-block;
    font-size: 0.8rem;
    font-family: var(--font-mono);
    padding: 4px 8px;
    border-radius: 4px;
    margin-right: 5px;
    margin-bottom: 5px;
    font-weight: 500;
}

.tag-structural { background-color: #795548; color: #fff; }
.tag-transportation { background-color: #4caf50; color: #fff; }
.tag-water { background-color: #03a9f4; color: #fff; }
.tag-tool { background-color: var(--color-accent-dark); color: var(--color-text-primary); }

.read-more-link {
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 700;
    transition: padding-left var(--transition-speed);
}
.read-more-link:hover {
    padding-left: 5px;
}
.read-more-link i {
    margin-left: 5px;
}

/* * ---------------------------------------
 * 7. Expertise Section - UPDATED ROUNDED EDGES
 * ---------------------------------------
 */
.expertise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--space-xl);
    background-color: var(--color-surface);
    padding: var(--space-xl);
    border-radius: var(--radius-md); /* Softer corners */
    box-shadow: var(--shadow-soft);
}

.skill-area h3 {
    margin-bottom: var(--space-md);
    color: var(--color-accent);
}
.skill-area h3 i {
    color: var(--color-accent-dark);
}

.software-tags {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.software-tags li {
    padding: 8px 12px;
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    color: var(--color-text-primary);
}

.focus-list {
    list-style: none;
}

.focus-list li {
    padding: var(--space-md);
    border-left: 4px solid var(--color-accent);
    margin-bottom: var(--space-md);
    border-radius: var(--radius-sm); /* Rounded list items */
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    transition: background-color var(--transition-speed);
}
.focus-list li:hover {
    background-color: var(--color-border); /* Subtle hover feedback */
}

.focus-list li strong {
    color: var(--color-accent);
    font-weight: 700;
    margin-right: var(--space-sm);
}


/* * ---------------------------------------
 * 8. About Section
 * ---------------------------------------
 */
.about-content {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: var(--space-xl);
    align-items: flex-start;
}

.profile-photo-placeholder {
    width: 200px;
    height: 200px;
    background-color: var(--color-accent-dark);
    border-radius: 50%;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 5px solid var(--color-accent);
    color: var(--color-background);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    flex-shrink: 0;
    text-align: center;
}

/* * ---------------------------------------
 * 9. Contact Section & Form - UPDATED ROUNDED EDGES & MICRO-INTERACTIONS
 * ---------------------------------------
 */
.contact-pitch {
    font-size: 1.25rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-lg);
}

.contact-form {
    display: grid;
    gap: var(--space-md);
    max-width: 600px;
    margin-bottom: var(--space-xl);
}

.contact-form input, .contact-form textarea {
    padding: var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm); /* Rounded inputs */
    background-color: var(--color-background);
    color: var(--color-text-primary);
    font-size: 1rem;
    transition: border-color var(--transition-speed);
}

.contact-form input:focus, .contact-form textarea:focus {
    border-color: var(--color-accent);
    outline: none;
}

.submit-btn {
    width: 100%;
    box-shadow: var(--shadow-soft);
}

.contact-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-lg);
}

.contact-item {
    font-size: 1.125rem;
    color: var(--color-text-primary);
    text-decoration: none;
    transition: all var(--transition-speed);
}

.contact-item:hover {
    color: var(--color-accent);
    transform: translateX(5px); /* Micro-interaction on link */
}

.contact-item i {
    margin-right: 8px;
    color: var(--color-accent);
}

/* * ---------------------------------------
 * 10. Footer
 * ---------------------------------------
 */
.site-footer {
    background-color: var(--color-surface);
    padding: var(--space-md) 0;
    border-top: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    font-size: 0.9rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.credit {
    font-family: var(--font-mono);
}

/* * ---------------------------------------
 * 11. Responsiveness
 * ---------------------------------------
 */
@media (max-width: 992px) {
    h1 { font-size: 3rem; }
    .nav-bar nav { display: none; }
    .nav-bar { justify-content: space-around; }
    .theme-toggle-btn { margin: 0; }
    .expertise-grid { padding: var(--space-lg); }
    .about-content { grid-template-columns: 1fr; text-align: center; }
    .profile-photo-placeholder { margin: 0 auto var(--space-md) auto; }
}

@media (max-width: 768px) {
    .container { padding: 0 var(--space-md); }
    h1 { font-size: 2.25rem; }
    h2 { font-size: 2rem; }
    .hero-summary { font-size: 1rem; }
    .hero-cta { flex-direction: column; gap: var(--space-md); }
    .secondary-link { margin-left: 0; }
    .expertise-grid { grid-template-columns: 1fr; gap: var(--space-lg); }
    .footer-content { flex-direction: column; gap: var(--space-sm); text-align: center; }
    .tool-ticker { flex-direction: column; gap: 0.5rem; }
    .featured { padding: 2rem 0; }
}