:root {
    --primary: #4a6fa5;
    --secondary: #166088;
    --dark: #0e1a2b;
    --light: #f8f9fa;
    --accent: #4fc3f7;
    --text: #e0e0e0;
    --text-dark: #333;
    --gray: #95a5a6;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background: var(--dark);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
}

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

/* Animations */
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Language Switcher */
.lang-switcher {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    display: flex;
    gap: 10px;
}

.lang-btn {
    background: rgba(255, 255, 255, 0.1);
    color: var(--accent);
    border: 1px solid var(--accent);
    padding: 8px 15px;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
}

.lang-btn:hover, .lang-btn.active {
    background: var(--accent);
    color: var(--dark);
}

/* Sections */
section {
    padding: 100px 0;
    min-height: auto; /* Changed from 100vh to fix Yandex issue */
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s, transform 0.6s;
}

section.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Hero Section */
.hero {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh; /* Keep vh only for hero section */
    background: linear-gradient(135deg, var(--dark), var(--secondary));
    text-align: center;
    padding: 0 20px;
}

.floating-name {
    animation: float 4s ease-in-out infinite;
    font-size: 3rem;
    margin-bottom: 20px;
    color: var(--light);
}

.floating-title {
    animation: float 4s ease-in-out infinite;
    animation-delay: 0.5s;
    font-size: 1.8rem;
    margin-bottom: 30px;
    color: var(--accent);
}

.contact-info {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 50px;
    flex-wrap: wrap;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--light);
    text-decoration: none;
    padding: 12px 20px;
    border-radius: 30px;
    background: rgba(255, 255, 255, 0.1);
    transition: all 0.3s;
}

.contact-item:hover {
    background: var(--accent);
    color: var(--dark);
    transform: translateY(-2px);
}

/* Education Section */
.education-item {
    background: rgba(255, 255, 255, 0.05);
    padding: 30px;
    border-radius: 15px;
    margin-bottom: 40px;
    border-left: 4px solid var(--accent);
}

.education-item h3 {
    color: var(--accent);
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.education-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 15px;
    color: var(--primary);
    font-weight: 500;
}

.courses-section {
    margin-top: 50px;
}

.courses-section h3 {
    color: var(--accent);
    margin-bottom: 30px;
    font-size: 1.5rem;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.course-item {
    background: rgba(255, 255, 255, 0.05);
    padding: 20px;
    border-radius: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-left: 3px solid var(--primary);
}

.course-item p {
    margin-right: 20px;
}

.course-item span {
    color: var(--accent);
    font-weight: bold;
    font-size: 0.9rem;
}

/* Projects Section */
.section-title {
    font-size: 2.5rem;
    margin-bottom: 50px;
    text-align: center;
    position: relative;
    display: inline-block;
    color: var(--accent);
}

.section-title::after {
    content: '';
    position: absolute;
    width: 50%;
    height: 4px;
    background: linear-gradient(90deg, var(--accent), var(--primary));
    bottom: -15px;
    left: 25%;
    border-radius: 2px;
}

.project-item {
    background: rgba(255, 255, 255, 0.05);
    padding: 40px;
    border-radius: 15px;
    margin-bottom: 50px;
    border-left: 4px solid var(--accent);
}

.project-header h3 {
    color: var(--accent);
    margin-bottom: 10px;
    font-size: 1.8rem;
}

.project-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    margin-bottom: 25px;
    align-items: center;
}

.project-role {
    color: var(--light);
    font-weight: 500;
    background: rgba(255, 255, 255, 0.1);
    padding: 5px 15px;
    border-radius: 20px;
}

.project-date {
    color: var(--primary);
    font-weight: bold;
}

.project-content ul {
    list-style: none;
}

.project-content li {
    margin-bottom: 15px;
    position: relative;
    padding-left: 30px;
    line-height: 1.7;
    font-size: 1.1rem;
}

.bullet {
    position: absolute;
    left: 0;
    color: var(--accent);
    font-size: 1.2rem;
    line-height: 1;
    top: 0.2em;
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 30px;
}

.skill-category {
    background: rgba(255, 255, 255, 0.05);
    padding: 30px;
    border-radius: 15px;
    border-left: 4px solid var(--primary);
}

.skill-category h3 {
    color: var(--accent);
    margin-bottom: 25px;
    padding-bottom: 10px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.skill-category ul {
    list-style: none;
}

.skill-category li {
    margin-bottom: 12px;
    position: relative;
    padding-left: 25px;
    transition: transform 0.3s;
}

.skill-category li:hover {
    transform: translateX(5px);
}

.skill-category li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--accent);
    font-size: 1.2em;
}

/* Footer */
footer {
    text-align: center;
    padding: 60px 0;
    background: rgba(0, 0, 0, 0.3);
}

footer h3 {
    color: var(--accent);
    margin-bottom: 30px;
    font-size: 1.8rem;
}

.copyright {
    color: var(--gray);
    margin-top: 30px;
    font-size: 0.9rem;
}

/* Mobile Optimization */
@media screen and (max-width: 768px) {
    section {
        padding: 80px 0;
        min-height: auto;
    }

    .floating-name {
        font-size: 2.2rem;
    }

    .floating-title {
        font-size: 1.4rem;
    }

    .contact-info {
        flex-direction: column;
        align-items: center;
    }

    .contact-item {
        width: 100%;
        max-width: 280px;
    }

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

    .project-item {
        padding: 25px;
    }

    .project-content li {
        font-size: 1rem;
    }

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

@media screen and (max-width: 480px) {
    .floating-name {
        font-size: 1.8rem;
    }

    .floating-title {
        font-size: 1.2rem;
    }

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

    .project-item {
        padding: 20px;
    }

    .project-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    .project-content li {
        padding-left: 25px;
    }

    .bullet {
        font-size: 1rem;
    }
}