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

:root {
    --primary-color: #0066cc;
    --primary-dark: #0052a3;
    --secondary-color: #6c757d;
    --text-color: #333;
    --text-light: #666;
    --bg-color: #ffffff;
    --bg-alt: #f8f9fa;
    --border-color: #e0e0e0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s ease;
    --hero-gradient-start: #667eea;
    --hero-gradient-end: #764ba2;
    --highlight-color: #ffd700;
    --btn-hover-bg: #f0f0f0;
    --footer-dark-bg: #0f0f0f;
}

[data-theme="dark"] {
    --primary-color: #4da3ff;
    --primary-dark: #66b3ff;
    --secondary-color: #a0a0a0;
    --text-color: #e4e4e4;
    --text-light: #b0b0b0;
    --bg-color: #1a1a1a;
    --bg-alt: #2a2a2a;
    --border-color: #3a3a3a;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.5);
    --hero-gradient-start: #4a5568;
    --hero-gradient-end: #2d3748;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Skip Link for Accessibility */
.skip-link {
    position: absolute;
    top: -100px;
    left: 0;
    background: var(--primary-color);
    color: white;
    padding: 8px 16px;
    text-decoration: none;
    border-radius: 0 0 4px 0;
    z-index: 2000;
    font-weight: 600;
}

.skip-link:focus {
    top: 0;
}

/* Focus Styles for Accessibility */
a:focus,
button:focus,
.hamburger:focus {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* Header & Navigation */
.header {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

[data-theme="dark"] .header {
    background: rgba(26, 26, 26, 0.95);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

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

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

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

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

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

/* Theme Toggle */
.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: none;
    background: transparent;
    cursor: pointer;
    border-radius: 50%;
    transition: var(--transition);
    margin-left: 1rem;
}

.theme-toggle:hover {
    background: var(--bg-alt);
}

.theme-toggle svg {
    color: var(--text-color);
}

.sun-icon {
    display: none;
}

.moon-icon {
    display: block;
}

[data-theme="dark"] .sun-icon {
    display: block;
}

[data-theme="dark"] .moon-icon {
    display: none;
}

/* Hamburger Menu */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: space-around;
    width: 30px;
    height: 30px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 1001;
}

.hamburger-line {
    width: 100%;
    height: 3px;
    background: var(--text-color);
    border-radius: 3px;
    transition: var(--transition);
    transform-origin: center;
}

.hamburger.active .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translate(8px, 8px);
}

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

.hamburger.active .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translate(8px, -8px);
}

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--hero-gradient-start) 0%, var(--hero-gradient-end) 100%);
    color: white;
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

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

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    opacity: 0.9;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.8;
}

.hero-links {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    padding: 12px 24px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    border: 2px solid transparent;
}

.btn svg {
    flex-shrink: 0;
}

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

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

.btn-secondary {
    background: transparent;
    color: white;
    border-color: white;
}

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

/* Sections */
.section {
    padding: 80px 0;
}

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

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    text-align: center;
    color: var(--text-color);
}

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

.about-text p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    color: var(--text-light);
    line-height: 1.8;
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.skill-category {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
    transition: var(--transition), background-color 0.3s ease, color 0.3s ease;
}

[data-theme="dark"] .skill-category {
    background: var(--bg-alt);
}

.skill-category:hover {
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}

.skill-category-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
}

[data-theme="dark"] .skill-category-title {
    color: var(--primary-color);
}

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

.skill-list li {
    padding: 0.5rem 0;
    color: var(--text-light);
    position: relative;
    padding-left: 1.5rem;
}

[data-theme="dark"] .skill-list li {
    color: var(--text-light);
}

.skill-list li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

/* Footer */
.footer {
    background: var(--text-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
}

[data-theme="dark"] .footer {
    background: var(--footer-dark-bg);
    color: var(--text-light);
}

/* Responsive Design */
@media (max-width: 768px) {
    .about-text p {
        text-align: justify;
    }

    .hamburger {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        max-width: 300px;
        height: 100vh;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(10px);
        flex-direction: column;
        gap: 0;
        padding: 80px 2rem 2rem;
        box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
        transition: right 0.3s ease;
        z-index: 1000;
        overflow-y: auto;
    }

    [data-theme="dark"] .nav-links {
        background: rgba(26, 26, 26, 0.98);
        box-shadow: -2px 0 10px rgba(0, 0, 0, 0.5);
    }

    .nav-links.active {
        right: 0;
    }

    .nav-overlay {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(0, 0, 0, 0.5);
        z-index: 999;
    }

    .nav-overlay.active {
        display: block;
    }

    body.menu-open {
        overflow: hidden;
    }

    .nav-links li {
        width: 100%;
        border-bottom: 1px solid var(--border-color);
    }

    .nav-links a {
        display: block;
        padding: 1rem 0;
        font-size: 1.1rem;
    }

    .nav-links a::after {
        display: none;
    }

    .hero {
        padding: 80px 0 50px;
    }

    .hero-title {
        font-size: 2.2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    .hero-links {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 300px;
        justify-content: center;
    }

    .section {
        padding: 60px 0;
    }

    .section-title {
        font-size: 2rem;
        margin-bottom: 2rem;
    }

    .skills-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

    .hero {
        padding: 60px 0 40px;
    }

    .hero-title {
        font-size: 1.8rem;
    }

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .section {
        padding: 48px 0;
    }

    .section-title {
        font-size: 1.6rem;
    }

    .skill-category {
        padding: 1.5rem;
    }
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}