/* Base Variables */
:root {
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.6s cubic-bezier(0.16, 1, 0.3, 1);
    
    /* Layout */
    --max-width: 1000px;
    --border-radius: 12px;
    --section-padding: 5rem 1.5rem;
}

/* Dark Mode (Default) */
[data-theme="dark"] {
    --bg-main: #121212;
    --bg-alt: #1a1a1a;
    --bg-card: #222222;
    --text-main: #f8f9fa;
    --text-muted: #adb5bd;
    --accent: #FF7A00; /* Vibrant Orange */
    --accent-hover: #e66e00;
    --border-color: #333333;
    --shadow: 0 8px 30px rgba(0,0,0,0.4);
    --header-bg: rgba(18, 18, 18, 0.85);
}

/* Light Mode */
[data-theme="light"] {
    --bg-main: #f8f9fa;
    --bg-alt: #ffffff;
    --bg-card: #ffffff;
    --text-main: #212529;
    --text-muted: #6c757d;
    --accent: #E65C00; /* Deep Orange */
    --accent-hover: #cc5200;
    --border-color: #e9ecef;
    --shadow: 0 8px 30px rgba(0,0,0,0.08);
    --header-bg: rgba(248, 249, 250, 0.85);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    line-height: 1.6;
    transition: background-color var(--transition-normal), color var(--transition-normal);
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Outfit', sans-serif;
    font-weight: 700;
    color: var(--text-main);
    line-height: 1.2;
}

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

ul {
    list-style: none;
}

.highlight {
    color: var(--accent);
}

/* Utility Classes */
.section {
    padding: var(--section-padding);
}

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

.alt-bg {
    background-color: var(--bg-alt);
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 3rem;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 60px;
    height: 4px;
    background-color: var(--accent);
    border-radius: 2px;
}

/* Header & Nav */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: var(--header-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: 'Outfit', sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -1px;
}

.logo::after {
    content: '.';
    color: var(--accent);
}

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

.nav-link {
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
    color: var(--text-muted);
}

.nav-link:hover, .nav-link.active {
    color: var(--text-main);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent);
    transition: width var(--transition-fast);
}

.nav-link:hover::after, .nav-link.active::after {
    width: 100%;
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-main);
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color var(--transition-fast);
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all var(--transition-fast);
    cursor: pointer;
}

.btn-primary {
    background-color: var(--accent);
    color: #ffffff;
    border: 2px solid var(--accent);
}

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

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

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

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px; /* Offset for header */
}

.hero-content {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 4rem;
}

.hero-text {
    flex: 1;
}

.hero-text h1 {
    font-size: 3.5rem;
    margin-bottom: 0.5rem;
}

.hero-text h2 {
    font-size: 1.5rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.hero-text h3 {
    font-size: 1.25rem;
    color: var(--text-main);
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.hero-text p {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    max-width: 600px;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
}

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

.social-links a {
    font-size: 1.8rem;
    color: var(--text-muted);
}

.social-links a:hover {
    color: var(--accent);
    transform: translateY(-3px);
}

.hero-image {
    flex: 0 0 350px;
}

.profile-pic {
    width: 350px;
    height: 350px;
    border-radius: 50%;
    object-fit: cover;
    object-position: center 15%;
    border: 4px solid var(--border-color);
    box-shadow: var(--shadow);
    transition: border-color var(--transition-normal), transform var(--transition-slow);
}

.profile-pic:hover {
    border-color: var(--accent);
    transform: scale(1.02);
}

/* Experience Timeline */
.timeline {
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 15px;
    top: 0;
    height: 100%;
    width: 2px;
    background-color: var(--border-color);
}

.timeline-item {
    position: relative;
    padding-left: 3rem;
    margin-bottom: 3rem;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-dot {
    position: absolute;
    left: 8px;
    top: 5px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background-color: var(--accent);
    border: 3px solid var(--bg-main);
    box-shadow: 0 0 0 3px var(--accent);
}

.timeline-content {
    background-color: var(--bg-card);
    padding: 2rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.timeline-content:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.timeline-header h3 {
    font-size: 1.3rem;
    margin-bottom: 0.2rem;
}

.timeline-header h4 {
    font-size: 1rem;
    color: var(--text-muted);
    font-weight: 500;
}

.timeline-date {
    font-size: 0.9rem;
    color: var(--accent);
    font-weight: 600;
    background-color: rgba(255, 122, 0, 0.1);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
}

.timeline-details {
    list-style: none;
}

.timeline-details li {
    margin-bottom: 0.8rem;
    position: relative;
    padding-left: 1.5rem;
    color: var(--text-muted);
}

.timeline-details li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--accent);
}

.timeline-details li strong {
    color: var(--text-main);
}

/* Cards (Education & Projects) */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.card {
    background-color: var(--bg-card);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    transition: transform var(--transition-fast), border-color var(--transition-fast);
    height: 100%;
}

.card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
}

.card-icon {
    font-size: 2.5rem;
    color: var(--accent);
    margin-bottom: 1.5rem;
}

.card-header {
    margin-bottom: 0.5rem;
}

.card-header h3 {
    font-size: 1.25rem;
    margin-bottom: 0.2rem;
}

.card-location {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.card-subtitle {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-main);
}

.card-subtitle span {
    color: var(--accent);
    font-weight: 500;
}

.card-details {
    list-style: none;
    color: var(--text-muted);
    font-size: 0.95rem;
}

.card-details li {
    margin-bottom: 0.5rem;
}

.card-details strong {
    color: var(--text-main);
}

/* Project Cards Specifics */
.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.tag {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--accent);
    background-color: rgba(255, 122, 0, 0.1);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
}

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

.project-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* Skills Grid */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
}

.skill-category {
    background-color: var(--bg-card);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

.skill-category-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.skill-category-header i {
    font-size: 2rem;
    color: var(--accent);
}

.skill-category-header h3 {
    font-size: 1.3rem;
}

.skill-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
}

.skill-chips span {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    padding: 0.6rem 1.2rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all var(--transition-fast);
}

.skill-chips span:hover {
    border-color: var(--accent);
    color: var(--accent);
}

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

footer p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Animations */
.animate-up {
    opacity: 0;
    transform: translateY(30px);
    animation: fadeUp var(--transition-slow) forwards;
}

.animate-in-right {
    opacity: 0;
    transform: translateX(30px);
    animation: fadeInRight var(--transition-slow) forwards;
}

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }
.delay-5 { animation-delay: 0.5s; }

@keyframes fadeUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInRight {
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Reveal on Scroll */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: all var(--transition-slow);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 900px) {
    .hero-content {
        flex-direction: column-reverse;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-text h1 { font-size: 2.8rem; }
    .hero-text h2 { font-size: 1.3rem; }
    .hero-text h3 { font-size: 1.1rem; }
    
    .hero-actions, .social-links {
        justify-content: center;
    }
    
    .profile-pic {
        width: 250px;
        height: 250px;
    }
}

@media (max-width: 480px) {
    .section {
        padding: 3rem 1rem;
    }
    
    .hero-text h1 { font-size: 2.3rem; }
    .hero-text h2 { font-size: 1.1rem; }
    
    .profile-pic {
        width: 200px;
        height: 200px;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .hero-actions {
        flex-direction: column;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none; /* In a real app, implement a hamburger menu here */
    }
    
    .section {
        padding: 4rem 1rem;
    }
    
    .timeline-header {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
}