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

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--bg-white);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

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

.nav-link {
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

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

/* Hamburger Button */
.hamburger {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 36px;
    height: 36px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    border-radius: 6px;
    transition: background 0.2s;
}

.hamburger:hover {
    background: var(--bg-light);
}

.hamburger-line {
    display: block;
    width: 22px;
    height: 2.5px;
    background: var(--text-dark);
    border-radius: 2px;
    transition: transform 0.3s, opacity 0.3s;
}

.hamburger.active .hamburger-line:nth-child(1) {
    transform: translateY(7.5px) rotate(45deg);
}

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

.hamburger.active .hamburger-line:nth-child(3) {
    transform: translateY(-7.5px) rotate(-45deg);
}

/* Dropdown Menu */
.dropdown-menu {
    display: none;
    background: var(--bg-white);
    border-top: 1px solid var(--border-color);
    padding: 0.75rem 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.dropdown-menu.open {
    display: block;
    animation: slideDown 0.2s ease-out;
}

@keyframes slideDown {
    from { opacity: 0; transform: translateY(-8px); }
    to { opacity: 1; transform: translateY(0); }
}

.dropdown-link {
    display: block;
    padding: 0.6rem 1rem;
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 500;
    border-radius: 6px;
    transition: background 0.2s, color 0.2s;
}

.dropdown-link:hover {
    background: var(--bg-light);
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 2rem;
}

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

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

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

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

.cta-button {
    display: inline-block;
    padding: 1rem 2rem;
    background: white;
    color: var(--primary-color);
    text-decoration: none;
    border-radius: 50px;
    font-weight: 600;
    transition: transform 0.3s, box-shadow 0.3s;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

/* Sections */
.section {
    padding: 5rem 0;
}

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

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

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

.about-content p {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

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

.skill-card {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.skill-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.15);
}

.skill-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.skill-card p {
    color: var(--text-light);
}

/* Experience Section */
.experience-list {
    max-width: 800px;
    margin: 0 auto;
}

.experience-item {
    padding: 2rem;
    border-left: 3px solid var(--primary-color);
    margin-bottom: 2rem;
    background: white;
    border-radius: 5px;
}

.experience-item h3 {
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.experience-meta {
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 1rem;
}

.experience-item p {
    color: var(--text-light);
}

/* Contact Section */
.contact-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.contact-content p {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.contact-link {
    padding: 0.75rem 2rem;
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 50px;
    font-weight: 600;
    transition: background 0.3s, transform 0.3s;
}

.contact-link:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }

    .dropdown-menu.open {
        display: flex;
        flex-direction: column;
    }

    .dropdown-menu.open .nav-menu-mobile {
        display: flex;
        flex-direction: column;
        list-style: none;
        margin-bottom: 0.5rem;
        padding-bottom: 0.5rem;
        border-bottom: 1px solid var(--border-color);
    }

    .dropdown-menu.open .nav-menu-mobile .nav-link {
        display: block;
        padding: 0.6rem 1rem;
        border-radius: 6px;
    }

    .dropdown-menu.open .nav-menu-mobile .nav-link:hover {
        background: var(--bg-light);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .contact-links {
        flex-direction: column;
    }
}

/* Certifications Section */
.certifications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    max-width: 1000px;
    margin: 0 auto;
    justify-items: center;
}

.cert-card {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
    width: 100%;
    max-width: 320px;
}

.cert-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.15);
}

.cert-image {
    width: 100%;
    max-width: 200px;
    height: auto;
    margin-bottom: 1rem;
    border-radius: 8px;
}

.cert-card h3 {
    color: var(--text-dark);
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
}

.cert-issuer {
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.cert-date {
    color: var(--text-light);
    font-size: 0.9rem;
}