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

:root {
    --primary-color: #1a1a1a;
    --primary-dark: #000000;
    --secondary-color: #64748b;
    --text-primary: #1a1a1a;
    --text-secondary: #64748b;
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --border-color: #e5e5e5;
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius: 12px;
    --radius-sm: 8px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: linear-gradient(135deg, #2d2d2d 0%, #1a1a1a 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    background: var(--bg-primary);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

/* Header */
.header {
    background: linear-gradient(135deg, #2d2d2d 0%, #1a1a1a 100%);
    padding: 10px 20px;
    color: white;
    text-align: center;
}

.profile-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.profile-image {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    overflow: hidden;
    border: 4px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

.profile-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.profile-info {
    text-align: center;
}

.name {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 8px;
    letter-spacing: -0.5px;
}

.title {
    font-size: 1.25rem;
    opacity: 0.95;
    font-weight: 400;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-top: 20px;
    padding: 12px 28px;
    background: white;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    border-radius: 8px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    border: 2px solid transparent;
}

.download-btn:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.25);
    border-color: white;
}

.download-btn svg {
    width: 20px;
    height: 20px;
}

/* Tab Navigation */
.tab-navigation {
    display: flex;
    background: var(--bg-secondary);
    border-bottom: 2px solid var(--border-color);
    overflow-x: auto;
    scrollbar-width: none;
}

.tab-navigation::-webkit-scrollbar {
    display: none;
}

.tab-button {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 20px 24px;
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    white-space: nowrap;
}

.tab-button svg {
    width: 20px;
    height: 20px;
}

.tab-button:hover {
    color: var(--primary-color);
    background: rgba(37, 99, 235, 0.05);
}

.tab-button.active {
    color: var(--primary-color);
    background: var(--bg-primary);
}

.tab-button.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
}

/* Content */
.content {
    padding: 40px;
    min-height: 500px;
}

.tab-content {
    display: none;
    animation: fadeIn 0.4s ease;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section {
    margin-bottom: 48px;
}

.section:last-child {
    margin-bottom: 0;
}

.section-title {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 3px solid var(--primary-color);
    display: inline-block;
}

/* About Section */
.about-text {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

.skills-list {
    list-style: none;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
}

.skills-list li {
    padding: 16px 20px;
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    font-weight: 500;
    color: var(--text-primary);
    transition: all 0.3s ease;
    border: 2px solid transparent;
    text-align: center;
}

.skills-list li:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
    background: var(--bg-primary);
}

/* Timeline */
.timeline {
    position: relative;
    padding-left: 40px;
}

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

.timeline-item {
    position: relative;
    margin-bottom: 40px;
}

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

.timeline-marker {
    position: absolute;
    left: -44px;
    top: 8px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--primary-color);
    border: 3px solid var(--bg-primary);
    box-shadow: 0 0 0 2px var(--primary-color);
}

.timeline-content {
    background: var(--bg-secondary);
    padding: 24px;
    border-radius: var(--radius-sm);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.timeline-content:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.timeline-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.timeline-company {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 8px;
}

.timeline-date {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 16px;
    font-weight: 500;
}

.timeline-description {
    color: var(--text-secondary);
    margin-bottom: 16px;
    line-height: 1.7;
}

.timeline-list {
    list-style: none;
    padding: 0;
}

.timeline-list li {
    padding-left: 24px;
    margin-bottom: 8px;
    color: var(--text-secondary);
    position: relative;
}

.timeline-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

/* Certificates */
.certificates-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.certificate-card {
    background: var(--bg-secondary);
    padding: 32px 24px;
    border-radius: var(--radius-sm);
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.certificate-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.certificate-icon {
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    background: white;
    border-radius: 12px;
    padding: 10px;
    box-shadow: var(--shadow);
}

.certificate-icon img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
}

.certificate-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.certificate-issuer {
    font-size: 1rem;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 4px;
}

.certificate-date {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.certificate-description {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
}

.credential-link {
    display: inline-block;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9375rem;
    transition: all 0.3s ease;
}

.credential-link:hover {
    transform: translateX(4px);
    color: var(--text-primary);
}

/* Articles */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 24px;
}

.article-card {
    background: var(--bg-secondary);
    padding: 24px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    display: block;
}

.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.article-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.article-icon {
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
}

.article-icon svg {
    width: 20px;
    height: 20px;
    color: white;
}

.article-date {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.article-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 12px;
    line-height: 1.4;
}

.article-excerpt {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
}

.article-footer {
    display: flex;
    align-items: center;
    justify-content: flex-end;
}

.article-link {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.9375rem;
    transition: transform 0.3s ease;
    display: inline-block;
}

.article-card:hover .article-link {
    transform: translateX(4px);
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    padding: 40px;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 20px;
}

.social-link {
    width: 48px;
    height: 48px;
    background: var(--bg-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    transition: all 0.3s ease;
    text-decoration: none;
    border: 2px solid var(--border-color);
}

.social-link:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-4px);
    border-color: var(--primary-color);
}

.social-link svg {
    width: 24px;
    height: 24px;
}

.footer-text {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

/* Responsive */
@media (max-width: 768px) {
    body {
        padding: 0;
    }

    .container {
        border-radius: 0;
    }

    .header {
        padding: 40px 20px;
    }

    .name {
        font-size: 2rem;
    }

    .title {
        font-size: 1.125rem;
    }

    .download-btn {
        padding: 10px 24px;
        font-size: 0.9375rem;
    }

    .download-btn svg {
        width: 18px;
        height: 18px;
    }

    .tab-button {
        flex-direction: column;
        padding: 16px 12px;
        font-size: 0.875rem;
        gap: 4px;
    }

    .tab-button svg {
        width: 18px;
        height: 18px;
    }

    .content {
        padding: 24px 20px;
    }

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

    .certificates-grid,
    .articles-grid {
        grid-template-columns: 1fr;
    }

    .timeline {
        padding-left: 30px;
    }

    .timeline-marker {
        left: -35px;
    }
}

@media (max-width: 480px) {
    .profile-image {
        width: 100px;
        height: 100px;
    }

    .name {
        font-size: 1.75rem;
    }

    .title {
        font-size: 1rem;
    }

    .download-btn {
        padding: 10px 20px;
        font-size: 0.875rem;
    }
}