/* ========================================
   CSS VARIABLES
======================================== */
:root {
    /* Colors */
    --color-primary: #2c5aa0;
    --color-primary-dark: #1e3f73;
    --color-secondary: #5c7fa6;
    --color-accent: #4a90e2;
    
    --color-bg-main: #ffffff;
    --color-bg-secondary: #f8f9fa;
    --color-bg-cream: #faf8f5;
    --color-bg-light: #e8eef5;
    
    --color-text-primary: #1a1a1a;
    --color-text-secondary: #4a4a4a;
    --color-text-muted: #6c757d;
    --color-text-light: #ffffff;
    
    --color-border: #dee2e6;
    --color-border-light: #e9ecef;
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-heading: 'Playfair Display', Georgia, serif;
    
    --font-size-base: 12px; /*14*/
    --font-size-sm: 12px; /*14*/
    --font-size-lg: 16px; /*18*/
    --font-size-xl: 20px; /*24px*/
    
    --line-height-base: 1.6;
    --line-height-heading: 1.3;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    
    /* Layout */
    --container-width: 1800px;
    --header-height: 80px;
    --header-width: 1800px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
    
    /* Transitions */
    --transition-base: all 0.3s ease;
    --transition-fast: all 0.15s ease;
}

/* ========================================
   RESET & BASE STYLES
======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--color-text-primary);
    background-color: var(--color-bg-main);
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

ul, ol {
    list-style: none;
}

button {
    font-family: inherit;
    border: none;
    background: none;
    cursor: pointer;
}

/* ========================================
   TYPOGRAPHY
======================================== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    line-height: var(--line-height-heading);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-sm);
}

h1 {
    font-size: clamp(2rem, 4vw, 3.5rem);
}

h2 {
    font-size: clamp(1.75rem, 3vw, 2.5rem);
}

h3 {
    font-size: clamp(1.5rem, 2.5vw, 2rem);
}

p {
    margin-bottom: var(--spacing-sm);
}

/* ========================================
   LAYOUT
======================================== */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.main {
    min-height: calc(100vh - var(--header-height) - 300px);
    padding: var(--spacing-xl) 0;
}

.section {
    margin-bottom: var(--spacing-xxl);
}

.section__title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    position: relative;
    padding-bottom: var(--spacing-sm);
}

.section__title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background: linear-gradient(to right, var(--color-primary), var(--color-accent));
    border-radius: var(--radius-sm);
}

/* ========================================
   HEADER
========================================  вопросевич*/
.header {
    background-color: var(--color-bg-main);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    height: var(--header-height);
    max-width: var(--header-width);
    margin: 0 auto; /* Центрирование хедера */
}

.header__content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-height);
}

/* Logo */
.logo__text {
    font-family: var(--font-heading);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: 0.5px;
}

.logo a:hover .logo__text {
    color: var(--color-accent);
}

/* Navigation */
.nav__list {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
}
/* Старое

.nav__link {
    font-weight: 500;
    color: var(--color-text-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    position: relative;
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 80%;
    height: 2px;
    background-color: var(--color-primary);
    transition: transform 0.3s ease;
}

.nav__link:hover,
.nav__link.active {
    color: var(--color-primary);
}

.nav__link:hover::after,
.nav__link.active::after {
    transform: translateX(-50%) scaleX(1);
}  */

.nav__link {
    font-weight: 500;
    color: var(--color-text-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    display: inline-flex;
    align-items: center;
    transition: var(--transition-base);
    /* Создаем невидимую границу заранее, чтобы текст не прыгал */
    border-bottom: 2px solid transparent; 
}

/* Убираем старый псевдоэлемент, если он остался */
.nav__link::after {
    display: none !important;
}

/* Состояние при наведении и активное состояние */
.nav__link:hover::after,
.nav__link.active::after {
    transform: scaleX(1);
}

.nav__link:hover,
.nav__link.active {
    color: var(--color-primary);
    background-color: rgba(44, 90, 160, 0.05);
    /* Линия появится четко под padding-ом */
    border-bottom-color: var(--color-primary); 
    border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: var(--spacing-xs);
}

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

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translateY(8px);
}

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

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translateY(-8px);
}

/* ========================================
   HERO SECTION
======================================== */
.hero {
    background: linear-gradient(135deg, var(--color-bg-light) 0%, var(--color-bg-cream) 100%);
    padding: var(--spacing-xxl) 0;
    text-align: center;
}

.hero__content {
    max-width: 800px;
    margin: 0 auto;
}

.hero__title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.hero__subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-secondary);
    font-style: italic;
    margin-bottom: var(--spacing-md);
}

.hero__description {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ========================================
   BUTTONS
======================================== */
.btn {
    display: inline-block;
    padding: 12px 32px;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-align: center;
    transition: var(--transition-base);
    border: 2px solid transparent;
}

.btn--primary {
    background-color: var(--color-primary);
    color: var(--color-text-light);
}

.btn--primary:hover {
    background-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

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

/* ========================================
   FOOTER
======================================== */
.footer {
    background: linear-gradient(to bottom, var(--color-bg-secondary), var(--color-bg-light));
    padding: var(--spacing-xxl) 0 var(--spacing-lg);
    margin-top: var(--spacing-xxl);
}

.footer__content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer__section h3 {
    font-size: var(--font-size-lg);
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.footer__text {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    line-height: 1.7;
}

.footer__links li,
.footer__contacts li {
    margin-bottom: var(--spacing-xs);
}

.footer__links a,
.footer__contacts a {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    transition: all 0.3s ease;
}

.footer__links a:hover,
.footer__contacts a:hover {
    color: var(--color-primary);
    padding-left: 5px;
}

.footer__contacts {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

/* Social Links */
.social-links {
    display: flex;
    gap: var(--spacing-sm);
}

.social-link {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-primary);
    color: var(--color-text-light);
    border-radius: 50%;
    font-weight: 600;
    font-size: var(--font-size-sm);
}

.social-link:hover {
    background-color: var(--color-accent);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.footer__bottom {
    text-align: center;
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.footer__copyright {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}


/* ========================================
   LANGUAGE SWITCHER (Glassmorphism)
======================================== */

.lang-switcher {
    display: flex;
    align-items: center;
    margin-left: var(--spacing-lg);
}

.lang-list {
    display: flex;
    align-items: center;
    gap: 6px;

    padding: 4px 8px;
    margin: 0;

    background: rgba(30, 63, 115, 0.08);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);

    border: 1px solid rgba(44, 90, 160, 0.2);
    border-radius: 20px;
    transition: var(--transition-base);
}

.lang-list:hover {
    background: rgba(30, 63, 115, 0.12);
    border-color: rgba(44, 90, 160, 0.4);
}

.lang-item {
    display: flex;
    align-items: center;
}

.lang-item a {
    text-decoration: none;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--color-primary);

    padding: 4px 8px;
    border-radius: 12px;

    transition: all 0.3s ease;
}

/* разделитель */

.lang-separator {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-primary);
    opacity: 0.6;
}

/* активный язык */

.current-lang a {
    background: var(--color-primary);
    color: #ffffff;
    box-shadow: 0 2px 8px rgba(30, 63, 115, 0.3);
}

.lang-item a:hover {
    background: rgba(44, 90, 160, 0.1);
    color: var(--color-accent);
}

/* мобилка */

@media (max-width: 1380px) {
    .lang-switcher {
        margin: var(--spacing-md) 0;
        justify-content: center;
    }
}


/* ========================================
   RESPONSIVE
======================================== */
@media (min-width: 769px) and (max-width: 1400px) {
    .logo {
        display: none;
    }
}


/* ========================================
   RESPONSIVE (MOBILE MENU REDESIGN)
======================================== */
@media (max-width: 768px) {
    :root {
        --header-height: 60px;
    }

    /* Кнопка бургера — возвращаем видимость */
    .menu-toggle {
        display: flex;
        z-index: 1100;
        position: relative;
    }

    .nav {
        position: fixed;
        top: var(--header-height);
        left: -100%;
        width: 100%;
        height: calc(100vh - var(--header-height));
        background-color: var(--color-bg-main);
        transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), left 0s;
        box-shadow: none;
        overflow-y: auto;
        border-top: 1px solid var(--color-border-light);
        z-index: 1050;
        display: block; /* Гарантируем отображение */
    }

    .nav.active {
        left: 0;
        box-shadow: var(--shadow-lg);
    }

    .nav__list {
        flex-direction: column;
        padding: var(--spacing-lg) 0;
        gap: 0; /* Убираем gap, так как используем границы */
    }

    .nav__item {
        width: 100%;
        border-bottom: 1px solid var(--color-border-light);
        opacity: 0;
        transform: translateX(-20px);
        transition: all 0.3s ease;
    }

    /* Каскадное появление пунктов */
    .nav.active .nav__item {
        opacity: 1;
        transform: translateX(0);
    }
    .nav.active .nav__item:nth-child(1) { transition-delay: 0.1s; }
    .nav.active .nav__item:nth-child(2) { transition-delay: 0.15s; }
    .nav.active .nav__item:nth-child(3) { transition-delay: 0.2s; }
    .nav.active .nav__item:nth-child(4) { transition-delay: 0.25s; }
    .nav.active .nav__item:nth-child(5) { transition-delay: 0.3s; }
    .nav.active .nav__item:nth-child(6) { transition-delay: 0.35s; }
    .nav.active .nav__item:nth-child(7) { transition-delay: 0.4s; }
    .nav.active .nav__item:nth-child(8) { transition-delay: 0.45s; }
    .nav.active .nav__item:nth-child(9) { transition-delay: 0.5s; }

    .nav__link {
        display: flex;
        align-items: center;
        width: 100%;
        padding: var(--spacing-md) var(--spacing-lg);
        text-align: left;
        font-family: var(--font-heading); /* Тот самый научный шрифт */
        font-size: 1.1rem;
        color: var(--color-text-primary);
        text-transform: none; /* Убираем капс для академичности */
        letter-spacing: 0;
    }

    /* Указатель в стиле оглавления */
    .nav__link::before {
        content: "§"; /* Символ параграфа для научного стиля */
        margin-right: 12px;
        color: var(--color-primary);
        font-size: 0.9rem;
        opacity: 0.6;
    }

    .nav__link:hover,
    .nav__link.active {
        background-color: var(--color-bg-secondary);
        color: var(--color-primary);
    }

    .nav__link::after {
        display: none; /* Убираем стандартное подчеркивание */
    }

    /* Дополнительная плашка внизу меню */
    .nav::after {
        content: "Тут можно что-то написать";
        display: block;
        padding: var(--spacing-lg);
        font-size: 0.75rem;
        color: var(--color-text-muted);
        text-transform: uppercase;
        letter-spacing: 1px;
    }

    .hero {
        padding: var(--spacing-xl) 0;
    }
    
    .footer__content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
}

@media (max-width: 480px) {
    .hero__title {
        font-size: 2rem;
    }
    
    .btn {
        width: 100%;
    }
}