/* ===== CSS Variables ===== */
:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-bg: #ffffff;
    --color-bg-alt: #f9fafb;
    --color-border: #e5e7eb;
    --color-shadow: rgba(0, 0, 0, 0.1);
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --transition: all 0.3s ease;
    --border-radius: 8px;
    --max-width: 1200px;
}

/* ===== Reset & Base ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
}

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

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

ul {
    list-style: none;
}

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

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

.section {
    padding: 5rem 0;
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 2.5rem;
    text-align: center;
    color: var(--color-text);
}

/* ===== Header & Navigation ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--color-bg);
    box-shadow: 0 1px 3px var(--color-shadow);
    z-index: 1000;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text);
}

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

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

.nav-link {
    font-weight: 500;
    color: var(--color-text-light);
    padding: 0.5rem 0;
    position: relative;
}

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

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

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background: var(--color-text);
    transition: var(--transition);
}

/* ===== Hero Section ===== */
.hero {
    padding: 8rem 0 5rem;
    background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-alt) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-text h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--color-text);
}

.hero-text h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 0.75rem;
}

.hero-tagline {
    font-size: 1rem;
    color: var(--color-text-light);
    margin-bottom: 1rem;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--color-text-light);
    margin-bottom: 2rem;
    max-width: 500px;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 1.5rem;
    border-radius: var(--border-radius);
    font-weight: 600;
    font-size: 1rem;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}

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

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

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

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

.hero-certification {
    margin-top: 1rem;
}

.certification-badge {
    display: inline-block;
    background: linear-gradient(135deg, #ff9900 0%, #ffad33 100%);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
}

.hero-image {
    display: flex;
    justify-content: center;
}

.profile-photo {
    width: 350px;
    height: 350px;
    object-fit: cover;
    border-radius: 50%;
    box-shadow: 0 20px 40px var(--color-shadow);
    border: 5px solid white;
}

/* ===== About Section ===== */
.about {
    background: var(--color-bg);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
}

.about-intro {
    font-size: 1.25rem;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--color-text-light);
}

.about-intro strong {
    color: var(--color-primary);
}

.about-highlights {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.highlight-card {
    background: var(--color-bg-alt);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

.highlight-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px var(--color-shadow);
}

.highlight-card h3 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
    color: var(--color-primary);
}

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

/* ===== Experience Section ===== */
.experience {
    background: var(--color-bg-alt);
}

.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

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

.timeline-item {
    position: relative;
    padding-left: 2.5rem;
    padding-bottom: 2.5rem;
}

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

.timeline-marker {
    position: absolute;
    left: -6px;
    top: 0;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--color-primary);
    border: 3px solid var(--color-bg-alt);
}

.timeline-content {
    background: var(--color-bg);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 10px var(--color-shadow);
}

.timeline-header h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 0.25rem;
}

.timeline-header .company {
    display: block;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 0.25rem;
}

.timeline-header .date {
    display: block;
    font-size: 0.875rem;
    color: var(--color-text-light);
}

.timeline-header .location {
    display: block;
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-bottom: 1rem;
}

.timeline-details {
    list-style: disc;
    padding-left: 1.25rem;
}

.timeline-details li {
    font-size: 0.95rem;
    color: var(--color-text-light);
    margin-bottom: 0.5rem;
}

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

/* ===== Skills Section ===== */
.skills {
    background: var(--color-bg);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.skill-category {
    background: var(--color-bg-alt);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
}

.skill-category h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--color-primary);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.skill-tag {
    background: var(--color-bg);
    color: var(--color-text-light);
    padding: 0.375rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

.skill-tag:hover {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* ===== Education Section ===== */
.education {
    background: var(--color-bg-alt);
}

.edu-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.edu-card {
    background: var(--color-bg);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 10px var(--color-shadow);
}

.edu-card h3 {
    font-size: 1.25rem;
    color: var(--color-primary);
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 2px solid var(--color-border);
}

.edu-item {
    margin-bottom: 1.5rem;
}

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

.edu-item strong {
    display: block;
    font-size: 1rem;
    color: var(--color-text);
    margin-bottom: 0.25rem;
}

.edu-item p {
    font-size: 0.95rem;
    color: var(--color-text-light);
    margin-bottom: 0.25rem;
}

.edu-item span {
    display: block;
    font-size: 0.875rem;
    color: var(--color-text-light);
}

.edu-item .date {
    color: var(--color-primary);
    font-weight: 500;
}

/* ===== Contact Section ===== */
.contact {
    background: var(--color-bg);
    text-align: center;
}

.contact-intro {
    font-size: 1.125rem;
    color: var(--color-text-light);
    margin-bottom: 2.5rem;
}

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

.contact-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.5rem;
    background: var(--color-bg-alt);
    border-radius: var(--border-radius);
    color: var(--color-text);
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

.contact-link:hover {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

.contact-link svg {
    flex-shrink: 0;
}

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

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer p {
    font-size: 0.875rem;
    color: var(--color-border);
}

.back-to-top {
    color: var(--color-border);
    font-size: 0.875rem;
}

.back-to-top:hover {
    color: white;
}

/* ===== Responsive Design ===== */
@media (max-width: 992px) {
    .skills-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--color-bg);
        flex-direction: column;
        padding: 2rem;
        gap: 1rem;
        box-shadow: 0 10px 20px var(--color-shadow);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }

    .hero-text h1 {
        font-size: 2.25rem;
    }

    .hero-text h2 {
        font-size: 1.25rem;
    }

    .hero-description {
        margin: 0 auto 2rem;
    }

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

    .hero-image {
        order: -1;
    }

    .profile-photo {
        width: 250px;
        height: 250px;
    }

    .about-highlights {
        grid-template-columns: 1fr;
    }

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

    .edu-grid {
        grid-template-columns: 1fr;
    }

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

    .footer .container {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .section {
        padding: 3rem 0;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .hero {
        padding: 6rem 0 3rem;
    }

    .hero-text h1 {
        font-size: 1.75rem;
    }

    .hero-buttons {
        flex-direction: column;
    }

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

    .profile-photo {
        width: 200px;
        height: 200px;
    }

    .timeline-content {
        padding: 1rem;
    }
}