:root {
    --primary-color: #4a90d9;
    --secondary-color: #5c6bc0;
    --accent-color: #ff6b9d;
    --text-primary: #333;
    --text-secondary: #666;
    --text-light: #999;
    --bg-primary: #fff;
    --bg-secondary: #f8f9fa;
    --bg-dark: #2c3e50;
    --border-color: #e1e4e8;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s ease;
}

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

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

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

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

ul {
    list-style: none;
}

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow);
    z-index: 1000;
}

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

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.tagline {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.nav-list {
    display: flex;
    gap: 30px;
}

.nav-list a {
    font-size: 0.95rem;
    color: var(--text-secondary);
    padding: 8px 0;
    position: relative;
}

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

.nav-list a:hover::after,
.nav-list a.active::after {
    width: 100%;
}

.nav-list a:hover,
.nav-list a.active {
    color: var(--primary-color);
}

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

.menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 25px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: var(--transition);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(74, 144, 217, 0.4);
}

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

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

.hero {
    padding: 140px 0 80px;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4ecf7 100%);
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 60px;
}

.hero-text {
    flex: 1;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 20px;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 30px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 15px;
}

.hero-avatar {
    flex-shrink: 0;
}

.avatar-placeholder {
    width: 180px;
    height: 180px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-hover);
}

.avatar-placeholder.large {
    width: 250px;
    height: 250px;
}

.avatar-placeholder span {
    font-size: 4rem;
    font-weight: 700;
    color: white;
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    margin-bottom: 50px;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 2px;
}

.skills {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.skill-card {
    background: white;
    padding: 35px;
    border-radius: 16px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    text-align: center;
}

.skill-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}

.skill-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.skill-card h3 {
    font-size: 1.3rem;
    color: var(--text-primary);
    margin-bottom: 12px;
}

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

.articles {
    padding: 100px 0;
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.article-card {
    background: white;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    cursor: pointer;
}

.article-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}

.article-image {
    height: 200px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 4rem;
}

.article-content {
    padding: 25px;
}

.article-tag {
    display: inline-block;
    padding: 4px 12px;
    background: rgba(74, 144, 217, 0.1);
    color: var(--primary-color);
    font-size: 0.8rem;
    border-radius: 20px;
    margin-bottom: 12px;
}

.article-title {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: 12px;
    transition: var(--transition);
}

.article-card:hover .article-title {
    color: var(--primary-color);
}

.article-excerpt {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
    line-height: 1.6;
}

.article-meta {
    display: flex;
    gap: 20px;
    font-size: 0.85rem;
    color: var(--text-light);
}

.loading {
    text-align: center;
    padding: 40px;
    font-size: 1.1rem;
    color: var(--text-secondary);
    background: var(--bg-secondary);
    border-radius: 12px;
}

.error {
    text-align: center;
    padding: 40px;
    font-size: 1.1rem;
    color: #e74c3c;
    background: rgba(231, 76, 60, 0.1);
    border-radius: 12px;
}

.about {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.about-content {
    display: flex;
    gap: 60px;
    align-items: center;
}

.about-image {
    flex-shrink: 0;
}

.about-text {
    flex: 1;
}

.about-text .section-title {
    text-align: left;
    margin-bottom: 30px;
}

.about-text .section-title::after {
    left: 0;
    transform: none;
}

.about-text p {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.8;
}

.about-info {
    margin-top: 30px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.info-item {
    display: flex;
    gap: 10px;
}

.info-label {
    font-weight: 600;
    color: var(--text-primary);
}

.info-value {
    color: var(--text-secondary);
}

.contact {
    padding: 100px 0;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 60px;
    align-items: start;
}

.contact-info p {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 30px;
}

.social-links {
    display: flex;
    gap: 20px;
}

.social-link {
    width: 50px;
    height: 50px;
    background: var(--bg-secondary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    transition: var(--transition);
}

.social-link:hover {
    background: var(--primary-color);
    transform: translateY(-5px);
}

.contact-form {
    background: white;
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--shadow);
}

.form-group {
    margin-bottom: 25px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 15px 20px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
    background: var(--bg-primary);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-group textarea {
    resize: vertical;
}

.contact-form .btn {
    width: 100%;
}

.footer {
    background: var(--bg-dark);
    color: white;
    padding: 40px 0;
    text-align: center;
}

.footer p {
    font-size: 0.95rem;
    margin-bottom: 8px;
}

.footer-tagline {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.85rem;
}

@media (max-width: 768px) {
    .header .container {
        flex-wrap: wrap;
    }

    .nav {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: white;
        box-shadow: var(--shadow);
        padding: 20px;
    }

    .nav.active {
        display: block;
    }

    .nav-list {
        flex-direction: column;
        gap: 15px;
    }

    .menu-toggle {
        display: flex;
    }

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

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

    .menu-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }

    .hero {
        padding: 120px 0 60px;
    }

    .hero-content {
        flex-direction: column-reverse;
        text-align: center;
    }

    .hero-title {
        font-size: 1.8rem;
    }

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

    .hero-avatar {
        margin-bottom: 30px;
    }

    .avatar-placeholder {
        width: 150px;
        height: 150px;
    }

    .avatar-placeholder span {
        font-size: 3rem;
    }

    .section-title {
        font-size: 1.6rem;
    }

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

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

    .about-content {
        flex-direction: column;
        text-align: center;
    }

    .about-text .section-title {
        text-align: center;
    }

    .about-text .section-title::after {
        left: 50%;
        transform: translateX(-50%);
    }

    .about-info {
        align-items: center;
    }

    .contact-content {
        grid-template-columns: 1fr;
    }
}