:root {
    --bg-color: #ffffff;
    --text-color: #334155;
    --text-light: #64748b;
    --primary-color: #0a66c2;
    --primary-hover: #084e96;
    --border-color: #e2e8f0;
    --tag-bg: #f1f5f9;
    --tag-text: #475569;
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
    
    /* Transitions */
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.title-sub {
    font-size: 1rem;
    font-weight: normal;
    color: var(--text-light);
}

.mt-2 { margin-top: 0.5rem; }
.mt-4 { margin-top: 1.5rem; }

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(8px);
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
}

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

.logo {
    display: inline-flex;
    align-items: center;
    text-decoration: none;
}

.logo-img {
    height: 42px;
    width: auto;
    display: block;
    object-fit: contain;
}

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

.nav-link {
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition);
}

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

/* Sections General */
.section {
    padding: 6rem 0;
    border-top: 1px solid var(--border-color);
}

.alt-bg {
    background-color: #f8fafc;
}

.section-title {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 3rem;
    letter-spacing: -0.02em;
    color: #0f172a;
}

/* Hero Section */
.hero {
    padding: 10rem 0 6rem;
    min-height: 90vh;
    display: flex;
    align-items: center;
    border-top: none;
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 4rem;
}

.hero-text {
    flex: 1;
}

.hero-title {
    font-size: 4rem;
    line-height: 1.1;
    font-weight: 700;
    letter-spacing: -0.03em;
    color: #0f172a;
    margin-bottom: 0.5rem;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.summary-text {
    font-size: 1.1rem;
    color: var(--text-light);
    max-width: 600px;
    line-height: 1.8;
}

/* Hero CTA row */
.hero-cta {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background-color: var(--primary-color);
    color: #ffffff;
    text-decoration: none;
    padding: 0.8rem 1.8rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 0.01em;
    box-shadow: 0 4px 14px rgba(10, 102, 194, 0.3);
    transition: var(--transition);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    box-shadow: 0 6px 20px rgba(10, 102, 194, 0.4);
    transform: translateY(-1px);
}

/* Outline CTA button */
.btn-outline {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--primary-color);
    background-color: transparent;
    padding: 0.78rem 1.6rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    border: 1.5px solid var(--primary-color);
    transition: var(--transition);
}

.btn-outline:hover {
    background-color: var(--primary-color);
    color: #fff;
    transform: translateY(-1px);
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    text-decoration: none;
    color: var(--text-color);
    background-color: var(--tag-bg);
    padding: 0.8rem 1.2rem;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.btn-secondary:hover {
    background-color: #e2e8f0;
}

/* ── Social Bar ── */
.social-bar {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.social-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    white-space: nowrap;
}

.social-icons {
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

/* Base social icon button */
.social-icon {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
    border-radius: 10px;
    font-size: 1.3rem;
    text-decoration: none;
    color: var(--text-light);
    background-color: var(--tag-bg);
    border: 1px solid var(--border-color);
    transition: all 0.22s cubic-bezier(0.4, 0, 0.2, 1);
}

.social-icon:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}

/* Brand colors on hover */
.social-icon.linkedin:hover {
    background-color: #0a66c2;
    border-color: #0a66c2;
    color: #fff;
    box-shadow: 0 8px 20px rgba(10, 102, 194, 0.35);
}

.social-icon.twitter:hover {
    background-color: #000000;
    border-color: #000000;
    color: #fff;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.25);
}

.social-icon.github:hover {
    background-color: #24292f;
    border-color: #24292f;
    color: #fff;
    box-shadow: 0 8px 20px rgba(36, 41, 47, 0.3);
}

/* Tooltip */
.social-tooltip {
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%) translateY(4px);
    background-color: #0f172a;
    color: #fff;
    font-size: 0.72rem;
    font-weight: 600;
    white-space: nowrap;
    padding: 0.3rem 0.65rem;
    border-radius: 5px;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.18s ease, transform 0.18s ease;
}

.social-tooltip::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 5px solid transparent;
    border-top-color: #0f172a;
}

.social-icon:hover .social-tooltip {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

.hero-image {
    flex: 0 0 400px;
}

.image-wrapper {
    width: 100%;
    aspect-ratio: 4/5;
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    background-color: var(--tag-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 10px 40px rgba(0,0,0,0.04);
}

.image-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: grayscale(10%);
    transition: var(--transition);
}

.image-wrapper:hover img {
    filter: grayscale(0%);
    transform: scale(1.02);
}

/* Skills Grid */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 2rem;
}

.skill-category {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: var(--transition);
}

.skill-category:hover {
    border-color: #cbd5e1;
    box-shadow: 0 4px 20px rgba(0,0,0,0.03);
    transform: translateY(-2px);
}

.skill-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.skill-header i {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.skill-header h3 {
    font-size: 1.15rem;
    font-weight: 600;
    color: #0f172a;
}

.skills-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.tag {
    background-color: var(--tag-bg);
    color: var(--tag-text);
    padding: 0.35rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    border: 1px solid transparent;
}

.group:hover .tag {
    border-color: #cbd5e1;
    background-color: #ffffff;
}

/* Education Timeline */
.timeline {
    position: relative;
    max-width: 800px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 7px;
    top: 0;
    height: 100%;
    width: 2px;
    background-color: var(--border-color);
}

.timeline-item {
    position: relative;
    padding-left: 3rem;
    padding-bottom: 3rem;
}

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

.timeline-dot {
    position: absolute;
    left: 0;
    top: 0.3rem;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background-color: var(--primary-color);
    border: 4px solid var(--bg-color);
    box-shadow: 0 0 0 1px var(--border-color);
}

.timeline-content {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: var(--transition);
}

.timeline-content:hover {
    border-color: #cbd5e1;
    box-shadow: 0 4px 20px rgba(0,0,0,0.03);
    transform: translateX(4px);
}

/* ── Professional Training Grid ── */
.cert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 2rem;
}

.cert-card {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.cert-card:hover {
    border-color: var(--primary-color);
    box-shadow: 0 12px 30px rgba(0,0,0,0.06);
    transform: translateY(-5px);
}

.cert-icon-wrapper {
    width: 60px;
    height: 60px;
    background-color: #e0f2fe;
    color: var(--primary-color);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
}

.cert-content {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.cert-status {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #0369a1;
    background-color: #f0f9ff;
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    width: fit-content;
}

.cert-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: #0f172a;
    line-height: 1.3;
}

.cert-org {
    font-weight: 600;
    color: var(--primary-color);
    font-size: 1rem;
}

.cert-desc {
    font-size: 0.95rem;
    color: var(--text-light);
    line-height: 1.6;
}

/* ── Existing Elements ── */
.date-badge {
    display: inline-block;
    background-color: #e0f2fe;
    color: #0284c7;
    font-size: 0.8rem;
    font-weight: 600;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    margin-bottom: 1rem;
}

.item-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #0f172a;
    margin-bottom: 0.4rem;
}

.item-org {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* Work / Projects Grid */
.work-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.project-card {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: var(--transition);
    height: 100%;
}

.project-card:hover {
    border-color: #94a3b8;
    box-shadow: 0 4px 20px rgba(0,0,0,0.03);
    transform: translateY(-2px);
}

.project-icon {
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.project-title {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: #0f172a;
}

.project-desc {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
}

.card-footer {
    border-top: 1px solid var(--border-color);
    padding-top: 1.5rem;
    margin-top: auto;
}

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
}

.project-link:hover {
    color: var(--primary-hover);
    gap: 0.75rem;
}

/* Footer Section */
.footer {
    padding: 8rem 0 4rem;
    text-align: center;
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-color);
}

.footer-title {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 1.5rem;
    color: #0f172a;
}

.footer-email a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1.25rem;
    font-weight: 500;
    transition: var(--transition);
}

.footer-email a:hover {
    text-decoration: underline;
    color: var(--primary-hover);
}

/* Responsive constraints */
@media (max-width: 992px) {
    .hero-content {
        flex-direction: column;
        text-align: center;
        padding-top: 4rem;
    }
    
    .hero-cta,
    .social-bar {
        justify-content: center;
    }

    .summary-text {
        margin: 1.5rem auto;
    }

    .hero-image {
        flex: 0 0 auto;
        width: 100%;
        max-width: 350px;
        order: -1;
        margin-bottom: 2rem;
    }

    .hero-title {
        font-size: 3rem;
    }
}

@media (max-width: 768px) {
    .hero {
        padding: 8rem 0 4rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

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

    .summary-text {
        font-size: 1rem;
    }

    .footer-title {
        font-size: 2rem;
    }

    .header-content {
        flex-direction: column;
        justify-content: center;
        gap: 0.5rem;
        height: auto;
        padding: 1rem 0;
    }

    .nav {
        gap: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .timeline-item {
        padding-left: 2rem;
    }

    .timeline-content {
        padding: 1.5rem;
    }
}