:root {
    --primary-color: #1a1a1a;
    --secondary-color: #ffffff;
    --accent-color: #007bff;
    --text-color: #333333;
    --bg-color: #ffffff;
    --header-height: 80px;
    --font-main: 'Filson Soft', 'Arial', sans-serif;
    --transition: all 0.3s ease;
}

@font-face {
    font-family: 'Filson Soft';
    src: url('../fonts/filson-soft-n4.woff2') format('woff2');
    font-weight: 400;
    font-style: normal;
}

body {
    margin: 0;
    font-family: var(--font-main);
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.6;
}

.header-main {
    position: fixed;
    top: 0;
    width: 100%;
    height: var(--header-height);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0,0,0,0.05);
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 50px;
    box-sizing: border-box;
    transition: var(--transition);
}

.logo a {
    text-decoration: none;
    color: var(--primary-color);
    font-weight: 700;
    font-size: 24px;
    letter-spacing: -0.5px;
}

.navigation ul {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
}

.navigation li {
    margin: 0 12px;
}

.navigation a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    text-transform: uppercase;
    font-size: 13px;
    letter-spacing: 0.5px;
    transition: var(--transition);
    position: relative;
}

.navigation a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition);
}

.navigation a:hover::after {
    width: 100%;
}

.lang-toggle {
    display: flex;
    gap: 10px;
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px;
}

.menu-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--primary-color);
    margin: 5px 0;
    transition: var(--transition);
}

.lang-toggle a {
    text-decoration: none;
    font-size: 12px;
    font-weight: 700;
    color: #999;
    padding: 4px 8px;
    border-radius: 4px;
    transition: var(--transition);
}

.lang-toggle a.active {
    color: var(--primary-color);
    background: #f0f0f0;
}

.lang-toggle a:hover:not(.active) {
    color: var(--primary-color);
}

main {
    margin-top: var(--header-height);
    padding: 80px 50px;
    max-width: 1200px;
    margin-left: auto;
    margin-right: auto;
    min-height: calc(100vh - var(--header-height) - 200px);
}

h1 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 30px;
    color: var(--primary-color);
}

footer {
    padding: 60px 50px;
    background: #6B5E52;
    color: #ffffff;
    text-align: center;
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contacts {
    font-size: 16px;
    letter-spacing: 0.5px;
}

.copyright {
    font-size: 13px;
    color: #ffffff;
}

/* Q&A Section Styles */
.qa-item {
    margin-bottom: 30px;
    padding: 25px;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    border-left: 5px solid var(--primary-color);
    transition: var(--transition);
}

.qa-item:hover {
    transform: translateX(5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.1);
}

.qa-question {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.qa-answer {
    font-size: 16px;
    color: var(--text-color);
    line-height: 1.8;
}

.qa-answer ul {
    margin-top: 10px;
    padding-left: 20px;
}

.qa-answer li {
    margin-bottom: 8px;
}

/* Review Styles */
.reviews-grid {
    display: block;
    max-width: 900px;
    margin: 40px auto;
}

.review-card {
    background: #fff;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
    display: flex;
    flex-direction: column;
    transition: var(--transition);
    margin-bottom: 40px;
}

.review-card:hover {
    box-shadow: 0 10px 40px rgba(0,0,0,0.1);
}

.review-header {
    display: flex;
    align-items: center;
    gap: 30px;
    margin-bottom: 30px;
    border-bottom: 1px solid #f0f0f0;
    padding-bottom: 25px;
}

.review-avatar {
    width: 120px;
    height: 120px;
    border-radius: 12px;
    background: #f0f0f0;
    overflow: hidden;
    flex-shrink: 0;
}

.review-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.review-meta h3 {
    margin: 0;
    font-size: 24px;
    color: var(--primary-color);
}

.review-meta .review-link {
    font-size: 14px;
    color: #007bff;
    text-decoration: none;
    word-break: break-all;
    display: block;
    margin-top: 5px;
}

.review-meta .review-link:hover {
    text-decoration: underline;
}

.review-text {
    font-size: 16px;
    color: var(--text-color);
    line-height: 1.8;
}

/* Content Page Styles */
.content-section {
    margin-bottom: 60px;
}

.content-section h2 {
    font-size: 32px;
    margin-bottom: 25px;
    border-bottom: 2px solid #f0f0f0;
    padding-bottom: 10px;
    color: var(--primary-color);
}

.content-section h3 {
    font-size: 24px;
    margin-top: 40px;
    margin-bottom: 20px;
    color: #444;
}

.content-section p {
    margin-bottom: 20px;
}

.content-section ul {
    margin-bottom: 20px;
    padding-left: 20px;
}

.content-section li {
    margin-bottom: 10px;
}

/* Publications Styles */
.year-group {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary-color);
    margin: 50px 0 25px 0;
    padding-bottom: 10px;
    border-bottom: 2px solid #f0f0f0;
}

.publication-item {
    background: #fff;
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    border-left: 5px solid #eee;
    transition: var(--transition);
}

.publication-item:hover {
    transform: translateX(5px);
    border-left-color: var(--primary-color);
    box-shadow: 0 8px 25px rgba(0,0,0,0.1);
}

.publication-number {
    display: inline-block;
    background: #f0f0f0;
    color: #666;
    font-size: 12px;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 4px;
    margin-bottom: 10px;
}

.publication-title {
    display: block;
    font-size: 18px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 10px;
    line-height: 1.4;
}

.publication-authors {
    font-size: 15px;
    color: #555;
    margin-bottom: 10px;
}

.publication-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    align-items: center;
    font-size: 13px;
    color: #888;
    margin-bottom: 10px;
}

.publication-year, .publication-type {
    font-weight: 600;
}

.publication-link {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    color: #007bff;
    text-decoration: none;
    font-weight: 600;
}

.publication-link:hover {
    text-decoration: underline;
}

.publication-details {
    font-size: 14px;
    color: #777;
    font-style: italic;
}

.warning-block {
    background: #fff5f5;
    border-left: 4px solid #ff4d4d;
    padding: 30px;
    margin: 40px 0;
    border-radius: 0 8px 8px 0;
}

.warning-label {
    font-weight: 700;
    text-transform: uppercase;
    font-size: 14px;
    letter-spacing: 1px;
    color: #ff4d4d;
    margin-bottom: 15px;
}

.warning-block p {
    margin-bottom: 0;
}

.warning-block p + p {
    margin-top: 15px;
}

.profile-section {
    display: flex;
    gap: 40px;
    align-items: flex-start;
    margin-bottom: 50px;
}

.profile-image {
    flex-shrink: 0;
    width: 150px;
    height: 200px;
    background: #f0f0f0;
    border-radius: 12px;
    overflow: hidden;
}

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

.profile-info h2 {
    font-size: 32px;
    margin-top: 0;
    margin-bottom: 20px;
    color: var(--primary-color);
}

@media (max-width: 900px) {
    .profile-section {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
}

@media (max-width: 1100px) {
    .header-main {
        padding: 0 20px;
    }

    .menu-toggle {
        display: block;
        order: 2;
    }

    .lang-toggle {
        order: 1;
        margin-right: auto;
        margin-left: 20px;
    }

    .navigation {
        position: fixed;
        top: var(--header-height);
        left: 0;
        width: 100%;
        background: #fff;
        height: 0;
        overflow: hidden;
        transition: height 0.3s ease;
        box-shadow: 0 10px 20px rgba(0,0,0,0.05);
    }

    .navigation.active {
        height: auto;
        padding: 20px 0;
    }

    .navigation ul {
        flex-direction: column;
        align-items: center;
        gap: 20px;
    }

    .navigation li {
        margin: 0;
    }

    .navigation a {
        font-size: 16px;
    }
}

/* Abstract Page Styles */
.abstract-body {
    font-family: 'Montserrat', sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    padding: 40px 20px;
    position: relative;
}

.abstract-container {
    max-width: 1000px;
    margin: 0 auto;
}

.paper-card {
    background: white;
    border-radius: 50px;
    padding: 60px 70px;
    box-shadow: 0 30px 60px rgba(0,0,0,0.1);
    border: 1px solid rgba(255,255,255,0.5);
    position: relative;
}

.journal-header {
    text-align: right;
    color: #ff6b6b;
    font-style: italic;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 2px dashed #e2e8f0;
    font-weight: 500;
}

.paper-card .title {
    font-size: 1.8rem;
    font-weight: 800;
    color: #2d3748;
    margin-bottom: 20px;
    line-height: 1.3;
}

.authors {
    font-size: 1.2rem;
    font-weight: 600;
    color: #ff6b6b;
    margin-bottom: 10px;
}

.affiliation {
    font-size: 1rem;
    color: #718096;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 2px solid #e2e8f0;
}

.affiliation i {
    margin-right: 8px;
    color: #48dbfb;
}

.abstract-label {
    font-size: 1.2rem;
    font-weight: 700;
    color: #5f27cd;
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.abstract-label i {
    font-size: 1.5rem;
}

.abstract-text {
    font-size: 1.1rem;
    color: #4a5568;
    line-height: 1.8;
    text-align: justify;
}

.abstract-text p {
    margin-bottom: 20px;
}

.keywords {
    margin-top: 40px;
    padding-top: 20px;
    border-top: 2px solid #e2e8f0;
    color: #718096;
    font-size: 0.95rem;
}

.keywords strong {
    color: #ff6b6b;
}

.back-link {
    display: inline-block;
    margin-top: 30px;
    color: #ff6b6b;
    text-decoration: none;
    font-weight: 600;
    transition: 0.3s;
}

.back-link:hover {
    transform: translateX(-5px);
    color: #5f27cd;
}

.status-badge {
    background: linear-gradient(135deg, #f6d365, #fda085);
    color: white;
    padding: 5px 15px;
    border-radius: 30px;
    display: inline-block;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.underline {
    text-decoration: underline;
}

.abstract-lang-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    display: flex;
    gap: 5px;
    background: white;
    padding: 5px;
    border-radius: 40px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.abstract-lang-btn {
    border: none;
    background: transparent;
    padding: 10px 25px;
    border-radius: 30px;
    font-weight: 700;
    cursor: pointer;
    font-size: 0.95rem;
    transition: 0.3s;
    color: #2d3748;
}

.abstract-lang-btn.active {
    background: #ff6b6b;
    color: white;
    box-shadow: 0 4px 15px rgba(255, 107, 107, 0.4);
}

/* Language Visibility for Abstracts */
body.abstract-body[lang="en"] .lang-ru {
    display: none !important;
}

body.abstract-body[lang="ru"] .lang-en {
    display: none !important;
}

@media (max-width: 768px) {
    .abstract-body { padding: 20px 10px; }
    .paper-card { padding: 30px 25px; }
    .paper-card .title { font-size: 1.8rem; }
    .authors { font-size: 1.2rem; }
    .abstract-lang-toggle { top: 10px; right: 10px; }
    .abstract-lang-btn { padding: 8px 15px; }
}