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

body {
    font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
    background: #05060a;
    color: #f5f5f5;
    line-height: 1.6;
    scroll-behavior: smooth;
    transition: background 0.3s ease, color 0.3s ease;
}

body.light {
    background: #f5f5f5;
    color: #111827;
}

/* Theme toggle */
.theme-toggle {
    position: fixed;
    top: 16px;
    right: 16px;
    z-index: 1000;
    cursor: pointer;
}
.theme-toggle img {
    width: 32px;
    height: 32px;
}

/* Header / Navbar */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 900;
    backdrop-filter: blur(12px);
    background: rgba(5, 6, 10, 0.7);
}
body.light .header {
    background: rgba(245, 245, 245, 0.85);
}
.navbar {
    max-width: 1100px;
    margin: 0 auto;
    padding: 12px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.logo {
    font-weight: 700;
    letter-spacing: 0.12em;
    font-size: 0.9rem;
}
.nav-links {
    list-style: none;
    display: flex;
    gap: 24px;
}
.nav-links a {
    text-decoration: none;
    color: inherit;
    font-size: 0.95rem;
    font-weight: 500;
}

/* Sections */
.section {
    max-width: 1100px;
    margin: 0 auto;
    padding: 120px 20px 80px;
}
.section-title {
    font-size: 2.2rem;
    text-align: center;
    margin-bottom: 10px;
}
.section-subtitle {
    text-align: center;
    margin-bottom: 40px;
    opacity: 0.8;
}

/* Hero */
.hero {
    min-height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}
.hero-bg {
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at top, #1f2937, #05060a);
    opacity: 0.9;
}
body.light .hero-bg {
    background: radial-gradient(circle at top, #e5f0ff, #f5f5f5);
}
.hero-content {
    position: relative;
    text-align: center;
    max-width: 720px;
}
.profile-img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 20px;
    border: 3px solid rgba(255, 255, 255, 0.4);
}
.hero h1 {
    font-size: 2.4rem;
    margin-bottom: 6px;
}
.hero h2 {
    font-size: 1.2rem;
    opacity: 0.85;
    margin-bottom: 18px;
}
.hero-text {
    font-size: 1.05rem;
    opacity: 0.9;
    margin-bottom: 16px;
}
.hero-text-secondary {
    font-size: 0.98rem;
    opacity: 0.85;
    margin-bottom: 24px;
}
.hero-actions {
    margin-bottom: 24px;
}
.primary-btn,
.secondary-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 22px;
    border-radius: 999px;
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 600;
    border: none;
}
.primary-btn {
    background: #2563eb;
    color: #f9fafb;
}
.secondary-btn {
    background: transparent;
    color: inherit;
    border: 1px solid rgba(148, 163, 184, 0.6);
}
.btn-icon {
    width: 20px;
    height: 20px;
}
.hero-scroll {
    margin-top: 16px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    opacity: 0.7;
    font-size: 0.85rem;
}
.hero-scroll img {
    width: 26px;
}

/* Impact */
.impact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 20px;
}
.impact-card {
    padding: 18px 20px;
    border-radius: 14px;
    background: rgba(15, 23, 42, 0.85);
    border: 1px solid rgba(148, 163, 184, 0.5);
}
body.light .impact-card {
    background: rgba(255, 255, 255, 0.95);
    border-color: rgba(148, 163, 184, 0.6);
}
.impact-card h3 {
    margin-bottom: 8px;
    font-size: 1.05rem;
}
.impact-card p {
    font-size: 0.95rem;
    opacity: 0.9;
}

/* Timeline */
.timeline {
    position: relative;
    margin-top: 20px;
    padding-left: 18px;
}
.timeline::before {
    content: "";
    position: absolute;
    left: 8px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, #2563eb, transparent);
}
.timeline-item {
    position: relative;
    margin-bottom: 26px;
}
.timeline-marker {
    position: absolute;
    left: 0;
    top: 18px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: #2563eb;
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.25);
}
.timeline-card {
    margin-left: 28px;
    padding: 16px 18px;
    border-radius: 14px;
    background: rgba(15, 23, 42, 0.8);
    border: 1px solid rgba(148, 163, 184, 0.4);
}
body.light .timeline-card {
    background: rgba(255, 255, 255, 0.9);
    border-color: rgba(148, 163, 184, 0.5);
}
.timeline-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 8px;
}
.company-logo {
    width: 40px;
    height: 40px;
    object-fit: contain;
}
.timeline-period {
    font-size: 0.85rem;
    opacity: 0.8;
}
.timeline-text {
    font-size: 0.95rem;
    opacity: 0.9;
}
.total-exp {
    margin-top: 30px;
    text-align: center;
    font-size: 1rem;
    font-weight: 600;
}

/* Certifications */
.cert-section {
    position: relative;
}
.cert-list details {
    background: rgba(15, 23, 42, 0.85);
    border-radius: 12px;
    padding: 14px 16px;
    margin-bottom: 12px;
    border: 1px solid rgba(148, 163, 184, 0.5);
    transition: all 0.25s ease;
}
body.light .cert-list details {
    background: rgba(255, 255, 255, 0.95);
    border-color: rgba(148, 163, 184, 0.6);
}
.cert-list details[open] {
    transform: translateY(-2px);
    border-color: #2563eb;
}
.cert-list summary {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 600;
}
.cert-list summary::-webkit-details-marker {
    display: none;
}
.cert-list img {
    width: 26px;
    height: 26px;
    object-fit: contain;
}
.cert-list p {
    margin-top: 10px;
    font-size: 0.9rem;
    opacity: 0.9;
}

/* Social */
.social-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
}
.social-links a {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 18px;
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.6);
    text-decoration: none;
    color: inherit;
    font-size: 0.95rem;
}
.social-links img {
    width: 22px;
    height: 22px;
}

/* Contact */
.contact-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 16px;
    margin-top: 20px;
}

/* Reveal animation */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}
.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    .section {
        padding-top: 100px;
    }
    .timeline::before {
        left: 6px;
    }
    .timeline-card {
        margin-left: 24px;
    }
}