:root {
    --bg-color: #ffffff;
    --text-color: #1a1a1a;
    --text-secondary: #666666;
    --border-color: #e5e5e5;
    --hover-bg: #f8f9fa;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #e5e5e5;
    --text-secondary: #a0a0a0;
    --border-color: #333333;
    --hover-bg: #252525;
}

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

*,
*::before,
*::after {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', sans-serif;
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--bg-color);
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 24px;
}

header {
    padding: 80px 0 60px;
    text-align: center;
    position: relative;
}

.theme-toggle {
    position: absolute;
    top: 30px;
    right: 30px;
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-color);
    transition: all 0.2s;
}

.theme-toggle:hover {
    background-color: var(--hover-bg);
}

.theme-toggle:focus-visible {
    outline: 2px solid var(--text-color);
    outline-offset: 2px;
}

.theme-icon {
    width: 20px;
    height: 20px;
}

.name {
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 12px;
    letter-spacing: -0.02em;
}

.title {
    font-size: 1.1rem;
    color: var(--text-secondary);
    font-weight: 400;
}

nav {
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    background-color: var(--bg-color);
    backdrop-filter: blur(10px);
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    gap: 32px;
    padding: 16px 0;
}

nav a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s;
}

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

nav a:focus-visible {
    outline: 2px solid var(--text-color);
    outline-offset: 4px;
    border-radius: 2px;
}

section {
    padding: 80px 0;
    border-bottom: 1px solid var(--border-color);
}

section:last-of-type {
    border-bottom: none;
}

.section-title {
    font-size: 1.8rem;
    margin-bottom: 40px;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.about-text {
    max-width: 700px;
    color: var(--text-secondary);
    line-height: 1.8;
}

.about-text p {
    margin-bottom: 12px;
}

.skills-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
}

.skill-item {
    padding: 16px 20px;
    border-left: 3px solid var(--text-secondary);
    background-color: var(--hover-bg);
    font-size: 0.95rem;
    color: var(--text-color);
}

.projects {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.project-card-link {
    text-decoration: none;
    color: inherit;
    display: block;
}

.project-card {
    padding: 24px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    transition: all 0.2s;
}

.project-card:hover {
    background-color: var(--hover-bg);
}

.project-card-link:hover .project-card {
    cursor: pointer;
}

.project-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.project-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.experience-item {
    margin-bottom: 32px;
    padding-bottom: 32px;
    border-bottom: 1px solid var(--border-color);
}

.experience-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.experience-date {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.experience-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.experience-company {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

footer {
    padding: 60px 0;
    text-align: center;
}

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

.social-icon {
    color: var(--text-color);
    font-size: 1.3rem;
    transition: opacity 0.2s;
}

.social-icon:hover {
    opacity: 0.6;
}

.social-icon:focus-visible {
    outline: 2px solid var(--text-color);
    outline-offset: 4px;
    border-radius: 4px;
}

footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .name {
        font-size: 2rem;
    }
    
    nav ul {
        gap: 20px;
    }
    
    section {
        padding: 60px 0;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
    
    .theme-toggle {
        top: 20px;
        right: 20px;
    }
}