:root {
    --color-background: #0a0a0a;
    --color-surface: #171717;
    --color-text: #ededed;
    --color-text-muted: #a1a1a1;
    --color-primary: #ffffff;
    --color-border: #262626;
    --color-hover: #2a2a2a;

    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --container-width: 75rem;
    --header-height: 7.3125rem;
    --radius: 0.5rem;
    --transition: 0.2s ease-in-out;
}

body.light-mode {
    --color-background: #ffffff;
    --color-surface: #f5f5f5;
    --color-text: #171717;
    --color-text-muted: #666666;
    --color-primary: #000000;
    --color-border: #e5e5e5;
    --color-hover: #f0f0f0;
}

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

html {
    scroll-behavior: smooth;
    font-size: 110%;
}

body {
    background-color: var(--color-background);
    color: var(--color-text);
    font-family: var(--font-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    transition: background-color 0.3s, color 0.3s;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    color: var(--color-text);
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    letter-spacing: -0.02em;
}

h2 {
    font-size: 2rem;
    font-weight: 600;
    letter-spacing: -0.01em;
}

h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

p {
    color: var(--color-text-muted);
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
}

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

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

ul {
    list-style: none;
}

/* Layout */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

section {
    padding: 1.5rem 0;
    scroll-margin-top: var(--header-height);
}

/* Header */
header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    position: fixed;
    top: 0;
    width: 100%;
    background-color: rgba(10, 10, 10, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid transparent;
    z-index: 100;
    transition: border-color 0.3s;
}

body.light-mode header {
    background-color: rgba(255, 255, 255, 0.9);
}

header.scrolled {
    border-bottom-color: var(--color-border);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    display: flex;
    flex-direction: column;
    text-decoration: none;
}

.logo-name {
    font-weight: 700;
    font-size: 1.625rem;
    letter-spacing: -0.01em;
    color: var(--color-text);
    line-height: 1.1;
}

.logo-role {
    font-size: 1.04rem;
    color: var(--color-text-muted);
    font-weight: 400;
    letter-spacing: 0.02em;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    color: var(--color-text-muted);
    font-size: 0.95rem;
    font-weight: 500;
}

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

.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--color-text);
    padding: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Mobile Nav */
.hamburger {
    display: none;
    cursor: pointer;
    flex-direction: column;
    gap: 0.375rem;
    z-index: 1001;
}

.hamburger span {
    width: 1.5rem;
    height: 0.125rem;
    background-color: var(--color-text);
    transition: 0.3s;
}

/* Hero */
.hero {
    padding-top: calc(var(--header-height) + 2rem);
    padding-bottom: 4rem;
    min-height: 80vh;
    display: flex;
    flex-direction: column;
    justify-content: flex-start; /* Align closer to top */
}

.hero-content {
    display: flex;
    flex-direction: column;
    gap: 3rem;
    max-width: 100%;
}

.hero-text-block {
    max-width: 50rem;
    margin: 0 auto;
    text-align: left; /* Keep left aligned for sleek look */
}

.hero-description {
    font-size: 1.15rem;
    line-height: 1.7;
    margin-bottom: 2rem;
    color: var(--color-text); /* Slightly brighter than muted */
}

.social-links {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.social-icon {
    color: var(--color-text-muted);
    transition: color var(--transition), transform var(--transition);
}

.social-icon:hover {
    color: var(--color-text);
    transform: translateY(-2px);
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 0.95rem;
    transition: all var(--transition);
    border: 1px solid transparent;
}

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

.btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

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

.btn-outline:hover {
    border-color: var(--color-text);
    background-color: rgba(255,255,255,0.05);
}

body.light-mode .btn-outline:hover {
    background-color: rgba(0,0,0,0.05);
}

/* Video */
.video-wrapper {
    width: 130%;
    position: relative;
    left: 50%;
    transform: translateX(-50%);
    max-width: 95vw;
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--color-border);
    background: #000;
}

.video-container {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 */
    height: 0;
    overflow: hidden;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

/* Tabs */
.tabs-container {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 0.5rem;
    flex-wrap: wrap;
}

.tab-btn {
    background: none;
    border: none;
    color: var(--color-text-muted);
    font-size: 1rem;
    font-weight: 500;
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: color var(--transition);
    position: relative;
}

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

.tab-btn.active {
    color: var(--color-text);
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -0.6rem; /* Align with border-bottom */
    left: 0;
    width: 100%;
    height: 0.125rem;
    background-color: var(--color-text);
}

/* Projects Grid */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(20rem, 1fr));
    gap: 2rem;
}

.project-card {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 2rem;
    transition: transform var(--transition), border-color var(--transition), opacity 0.3s ease;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    min-height: 28.125rem;
}

.project-card .video-container {
    width: 100%;
    margin-bottom: 1rem;
    border-radius: 4px;
    overflow: hidden;
}

.project-card:hover {
    transform: translateY(-4px);
    border-color: var(--color-text-muted);
}

.project-category-label {
    display: inline-block;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-primary);
    background: rgba(255,255,255,0.05);
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
    margin-bottom: 1rem;
    align-self: flex-start;
}

body.light-mode .project-category-label {
    background: rgba(0,0,0,0.05);
}

.project-card h3 {
    margin-bottom: 1rem;
    font-size: 1.4rem;
}

.project-description {
    font-size: 0.95rem;
    color: var(--color-text-muted);
    margin-bottom: 1.5rem;
}

.project-description p {
    margin-bottom: 0.5rem;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: auto;
}

.tag {
    font-size: 0.75rem;
    background-color: var(--color-background);
    color: var(--color-text-muted);
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    border: 1px solid var(--color-border);
}

/* Empty State */
.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 4rem 2rem;
    border: 1px dashed var(--color-border);
    border-radius: var(--radius);
    background-color: rgba(255,255,255,0.02);
    transition: opacity 0.3s ease;
}

.empty-state h3 {
    color: var(--color-text-muted);
    font-weight: 500;
}

/* Timeline / Experience */
.timeline-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.timeline-item {
    display: grid;
    grid-template-columns: 12.5rem 1fr;
    gap: 2rem;
    align-items: baseline;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 2rem;
}

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

.timeline-date {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    font-family: monospace;
}

.timeline-content h3 {
    margin-bottom: 0.25rem;
}

.timeline-role {
    font-size: 1rem;
    color: var(--color-text-muted);
    margin-bottom: 0.75rem;
    display: block;
}

/* Skills Grid */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(15.625rem, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.skill-item h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--color-text);
}

.skill-item p {
    font-size: 0.95rem;
}

/* Footer */
footer {
    padding: 3rem 0;
    border-top: 1px solid var(--color-border);
    margin-top: 4rem;
    text-align: center;
}

.footer-content p {
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

/* Mobile Media Queries */
@media (max-width: 768px) {
    .timeline-item {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .nav-links {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background-color: var(--color-background);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        font-size: 1.5rem;
        z-index: 1000;
    }

    .nav-links.active {
        display: flex;
    }

    .hamburger {
        display: flex;
    }

    .hamburger.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 6px);
    }
    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }
    .hamburger.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -6px);
    }

    body.menu-open header {
        backdrop-filter: none;
        -webkit-backdrop-filter: none;
    }

    .hero {
        padding-top: calc(var(--header-height) + 1rem);
    }

    .logo-name {
        font-size: 1.43rem;
    }

    .logo-role {
        font-size: 0.98rem;
    }

    .tabs-container {
        gap: 0.5rem;
    }

    .tab-btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.9rem;
    }
}