/* ========== СБРОС И ПЕРЕМЕННЫЕ ========== */
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    :root {
      --bg: #ffffff;
      --text: #222;
      --card-bg: #fff;
      --accent: #b8860b; /* золотой */
      --nav-bg: #f8f8f8;
      --footer-bg: #f0f0f0;
      --footer-text: #333;
      --shadow: rgba(0,0,0,0.1);
      --container-width: 1200px;
    }

    [data-theme="dark"] {
      --bg: #121212;
      --text: #f0f0f0;
      --card-bg: #1e1e1e;
      --nav-bg: #0f0f0f;
      --footer-bg: #1a1a1a;
      --footer-text: #ddd;
      --shadow: rgba(0,0,0,0.4);
    }

    body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.6;
      transition: background-color 0.4s ease, color 0.4s ease;
      overflow-x: hidden;
    }

    .container {
      width: min(100%, var(--container-width));
      margin: 0 auto;
      padding: 0 1rem;
    }

    /* ========== НАВИГАЦИЯ ========== 
    .main-nav {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 1rem 2rem;
      background-color: var(--nav-bg);
      border-bottom: 2px solid var(--accent);
      position: relative;
      z-index: 100;
      animation: fadeInDown 0.6s ease;
    }*/
.main-nav {
  display: flex;
  justify-content: center; /* Горизонтальное центрирование */
  align-items: center;     /* Вертикальное центрирование (если высота фиксирована или не важна) */
  flex-wrap: wrap;         /* На случай, если элементы не помещаются в одну строку */
  padding: 1rem;
  gap: 1rem;               /* Промежуток между дочерними элементами */
 background-color: var(--nav-bg);
      border-bottom: 2px solid var(--accent);

}

    #logo img {
      height: 90px;
      transition: transform 0.3s;
    }

    #logo:hover img {
      transform: scale(1.05);
    }

    .nav {
      display: flex;
      list-style: none;
      gap: 1rem;
    }

    .nav .btn {
      padding: 0.5rem 1rem;
      border-radius: 6px;
      transition: all 0.25s ease;
    }

    .nav .btn.active,
    .nav .btn:hover {
      background-color: #f2cf79;
      color: #000 !important;
      transform: translateY(-2px);
    }

    .nav a {
      text-decoration: none;
      color: var(--text);
      font-weight: 600;
    }

    .theme-toggle {
      background: none;
      border: 1px solid var(--accent);
      color: var(--accent);
      padding: 0.4rem 0.8rem;
      border-radius: 6px;
      cursor: pointer;
      font-weight: 600;
      transition: all 0.3s;
 

    }

    .theme-toggle:hover {
      background-color: var(--accent);
      color: #000;

    }

    /* Бургер */
    .burger {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 30px;
  height: 21px;
  cursor: pointer;
  align-self: flex-start;
  margin-top: 4px;
}

.burger span {
  height: 3px;
  width: 100%;
  background-color: var(--text);
  transition: 0.3s;
  border-radius: 2px;
}

    /* ========== КАРТОЧКИ ========== */
    .materials-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 1.8rem;
      padding: 2.5rem 0;
    }

    .card {
      background-color: var(--card-bg);
      border-radius: 10px;
      overflow: hidden;
      box-shadow: 0 6px 16px var(--shadow);
      transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
      border: 1px solid var(--accent);
      opacity: 0;
      transform: translateY(30px);
      animation: slideUp 0.6s forwards;
    }

    .card.appear {
      opacity: 1;
      transform: translateY(0);
    }

    .card:hover {
      transform: translateY(-10px) scale(1.01);
      box-shadow: 0 12px 24px rgba(184, 134, 11, 0.3);
    }

    .card img {
      width: 100%;
      height: 250px;
      object-fit: cover;
      display: block;
      transition: transform 0.5s ease;
    }

    .card:hover img {
      transform: scale(1.03);
    }

    .card-content {
      padding: 1.2rem;
    }

    .card h3 {
      margin: 0.4rem 0;
      color: var(--accent);
      transition: all 0.3s ease;
      font-weight: 700;
    }
.card h4 {
      margin: 0.4rem 0;
      color: #d91d09;
      transition: all 0.3s ease;
      font-weight: 400;
font-family: FreeMono, monospace;
    }

    .card:hover h3,
    .card:hover h4 {
      color: #d4af37;
      text-shadow: 0 0 8px rgba(212, 175, 55, 0.6);
      transform: scale(1.03);
    }

    .card p {
      font-size: 0.95rem;
      color: var(--text);
      opacity: 0.85;
      margin-top: 0.6rem;
      transition: opacity 0.3s;
    }

    .card:hover p {
      opacity: 1;
    }

    /* ========== ФУТЕР ========== */
    footer {
      background-color: var(--footer-bg);
      color: var(--footer-text);
      padding: 2.5rem 0 1.5rem;
      margin-top: 2rem;
      animation: fadeIn 1s ease;
border-top: 2px solid var(--accent);
    }

    .footer-content {
      display: flex;
      flex-wrap: wrap;
      justify-content: space-between;
      align-items: center;
      gap: 1.5rem;
    }

    .logo img {
      height: 90px;
      opacity: 0.9;
      transition: opacity 0.3s;
    }

    .logo:hover img {
      opacity: 1;
    }

    .footer-links {
      display: flex;
      gap: 1.4rem;
      flex-wrap: wrap;
      justify-content: center;
    }

    .footer-links a {
      color: var(--accent);
      text-decoration: none;
      font-weight: 600;
      transition: all 0.25s;
      position: relative;
    }

    .footer-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 2px;
      background-color: var(--accent);
      transition: width 0.3s ease;
    }

    .footer-links a:hover {
      opacity: 0.9;
    }

    .footer-links a:hover::after {
      width: 100%;
    }

    .copyright {
      width: 100%;
      text-align: center;
      margin-top: 1.8rem;
      color: var(--footer-text);
      font-size: 0.95rem;
      opacity: 0.8;
    }

    /* ========== КНОПКА "ВВЕРХ" ========== */
    #back-to-top {
      position: fixed;
      bottom: 25px;
      right: 25px;
      width: 50px;
      height: 50px;
      background: var(--accent);
      color: #000;
      border: none;
      border-radius: 50%;
      font-size: 20px;
      font-weight: bold;
      cursor: pointer;
      display: none;
      box-shadow: 0 4px 12px rgba(0,0,0,0.25);
      transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
      z-index: 90;
      animation: pulse 2s infinite;
    }

    #back-to-top:hover {
      background: #d4af37;
      transform: translateY(-4px) scale(1.05);
      box-shadow: 0 6px 16px rgba(0,0,0,0.3);
    }

    /* ========== АНИМАЦИИ ========== */
    @keyframes fadeIn {
      from { opacity: 0; }
      to { opacity: 1; }
    }

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

    @keyframes slideUp {
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    @keyframes pulse {
      0% { box-shadow: 0 0 0 0 rgba(184, 134, 11, 0.4); }
      70% { box-shadow: 0 0 0 10px rgba(184, 134, 11, 0); }
      100% { box-shadow: 0 0 0 0 rgba(184, 134, 11, 0); }
    }

    /* ========== АДАПТИВНОСТЬ ========== */
    @media (max-width: 1250px) {
      .materials-grid { grid-template-columns: repeat(3, 1fr); }
    }

    @media (max-width: 950px) {
      .materials-grid { grid-template-columns: repeat(2, 1fr); }

      .nav {
        position: fixed;
        top: 70px;
        left: -100%;
        flex-direction: column;
        background-color: var(--nav-bg);
        width: 100%;
        text-align: center;
        transition: 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
        padding: 2rem 0;
        gap: 1.4rem;
        box-shadow: 0 6px 16px rgba(0,0,0,0.2);
        z-index: 99;
      }

      .nav.active {
        left: 0;
      }

      .burger {
        display: flex;
      }

      .theme-toggle {
        display: none;
      }

      .main-nav {
        padding: 1rem;
      }
    }

    @media (max-width: 600px) {
      .materials-grid { grid-template-columns: 1fr; }
      .footer-content { flex-direction: column; text-align: center; }
      .copyright { margin-top: 1.2rem; }
      .nav { top: 65px; }
    }