:root {
    /* Colors - Default Dark Mode */
    --primary-color: #6366f1;
    /* Indigo 500 */
    --primary-hover: #818cf8;
    /* Indigo 400 */
    --secondary-color: #38bdf8;
    /* Sky 400 */
    --bg-color: #0f172a;
    /* Slate 900 */
    --surface-color: #1e293b;
    /* Slate 800 */
    --text-color: #f8fafc;
    /* Slate 50 */
    --text-muted: #94a3b8;
    /* Slate 400 */
    --border-color: #334155;
    /* Slate 700 */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.5);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.5), 0 2px 4px -2px rgb(0 0 0 / 0.5);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.5), 0 4px 6px -4px rgb(0 0 0 / 0.5);

    /* Typography */
    --font-sans: 'Inter', sans-serif;
}

/* Light Mode Variables */
[data-theme="light"] {
    --primary-color: #4f46e5;
    /* Indigo 600 */
    --primary-hover: #4338ca;
    /* Indigo 700 */
    --secondary-color: #0ea5e9;
    /* Sky 500 */
    --bg-color: #f8fafc;
    /* Slate 50 */
    --surface-color: #ffffff;
    --text-color: #0f172a;
    /* Slate 900 */
    --text-muted: #64748b;
    /* Slate 500 */
    --border-color: #e2e8f0;
    /* Slate 200 */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s ease;
}

ul {
    list-style: none;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: transparent;
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: var(--surface-color);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-outline {
    border: 1px solid var(--border-color);
    color: var(--text-color);
    background: transparent;
}

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

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

/* Navbar */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

[data-theme="dark"] header {
    background-color: rgba(15, 23, 42, 0.8);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 4.5rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
}

.logo span {
    color: var(--primary-color);
}

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

.nav-links a {
    font-weight: 500;
    color: var(--text-muted);
    position: relative;
}

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

.nav-links a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

#theme-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.25rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: background-color 0.2s ease;
}

#theme-toggle:hover {
    background-color: var(--border-color);
}

.hamburger {
    display: none;
    cursor: pointer;
    flex-direction: column;
    gap: 5px;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    transition: all 0.3s ease;
}

/* Hero Section */
#hero {
    padding: 8rem 0 6rem;
    display: flex;
    align-items: center;
    min-height: 80vh;
}

.hero-content {
    max-width: 800px;
}

.greeting {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

color: var(--text-muted);
margin-bottom: 1.5rem;
font-weight: 500;
}

.bio-short {
    font-size: 1.125rem;
    color: var(--text-muted);
    max-width: 600px;
    margin-bottom: 2.5rem;
}

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

/* Section Common */
section {
    padding: 5rem 0;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 3rem;
    text-align: center;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background-color: var(--primary-color);
    margin: 1rem auto 0;
    border-radius: 2px;
}

/* About Section */
.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about-text p {
    margin-bottom: 1.5rem;
    font-size: 1.125rem;
    color: var(--text-muted);
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.skill-category {
    background-color: var(--surface-color);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease;
}

.skill-category:hover {
    transform: translateY(-5px);
}

.skill-category h3 {
    font-size: 1.25rem;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.skill-items {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.skill-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background-color: var(--bg-color);
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

.skill-item i {
    color: var(--primary-color);
}

/* Projects Section */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.project-card {
    background-color: var(--surface-color);
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.project-content {
    padding: 2rem;
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.project-title {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.project-desc {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.project-tech span {
    font-size: 0.75rem;
    padding: 0.25rem 0.75rem;
    background-color: var(--bg-color);
    color: var(--primary-color);
    border-radius: 1rem;
    font-weight: 600;
    border: 1px solid var(--border-color);
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-color);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-sans);
    font-size: 1rem;
    transition: border-color 0.2s ease, ring 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.error-message {
    color: #ef4444;
    font-size: 0.875rem;
    margin-top: 0.25rem;
    display: block;
}

.form-status {
    margin-top: 1rem;
    text-align: center;
    font-weight: 500;
}

.form-status.success {
    color: #10b981;
}

.form-status.error {
    color: #ef4444;
}

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

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

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

.social-links a {
    font-size: 1.5rem;
    color: var(--text-muted);
    transition: color 0.2s ease, transform 0.2s ease;
}

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

.copyright {
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 4.5rem;
        left: 0;
        width: 100%;
        background-color: var(--surface-color);
        flex-direction: column;
        align-items: center;
        padding: 2rem 0;
        border-bottom: 1px solid var(--border-color);
        transform: translateY(-150%);
        transition: transform 0.3s ease;
        z-index: 999;
    }

    .nav-links.active {
        transform: translateY(0);
    }

    .hamburger {
        display: flex;
    }

    .hamburger.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .name {
        font-size: 2.5rem;
    }

    .tagline {
        font-size: 1.5rem;
    }

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

    .cta-buttons {
        justify-content: center;
    }
}