:root {
      --nav-bg: #001f3f;
      --nav-link: #fcbf49;
      --nav-link-hover: #e6aa30;
      --primary-color: #001f3f;
      --accent-color: #fcbf49;
      --background-gradient: linear-gradient(135deg, #f2f0e6 0%, #d6c796 100%);
      --text-color: #001f3f;
      --shadow-color: rgba(0, 31, 63, 0.2);
      --font-family: 'Poppins', sans-serif;
    }

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

    body {
      font-family: var(--font-family);
      background: var(--background-gradient);
      color: var(--text-color);
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      cursor: url('caliper_cursor.png'), auto;
    }

    header {
      background-color: var(--nav-bg);
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 14px 20px;
      box-shadow: 0 2px 6px var(--shadow-color);
      position: sticky;
      top: 0;
      z-index: 1000;
      flex-wrap: wrap;
    }

    .header-left {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--nav-link);
      letter-spacing: 0.1em;
      text-shadow: 0 0 5px var(--accent-color);
      text-transform: uppercase;
      white-space: nowrap;
    }

    nav {
      display: flex;
      flex-wrap: wrap;
      gap: 20px;
    }

    nav a {
      color: var(--nav-link);
      text-decoration: none;
      font-weight: 600;
      font-size: 1.05rem;
      padding: 8px 16px;
      border-radius: 8px;
      transition: 0.3s ease;
    }

    nav a:hover,
    nav a:focus {
      background-color: var(--nav-link-hover);
      color: var(--nav-bg);
      box-shadow: 0 0 10px var(--nav-link-hover);
    }

    nav a[aria-current="page"] {
      background-color: var(--nav-link);
      color: var(--nav-bg);
      font-weight: 700;
      box-shadow: 0 0 10px var(--nav-link);
    }

    main {
      flex: 1;
      max-width: 1000px;
      margin: 70px auto 100px;
      padding: 0 20px;
    }

    h1 {
      font-size: 3rem;
      font-weight: 800;
      color: var(--primary-color);
      text-align: center;
      margin-bottom: 40px;
      letter-spacing: 0.1em;
      text-transform: uppercase;
      text-shadow: 0 0 5px var(--accent-color);
    }

    section.content-section {
      background: #fff8e1;
      border-left: 8px solid var(--accent-color);
      box-shadow: 0 8px 20px var(--shadow-color);
      border-radius: 16px;
      padding: 30px;
      animation: fadeInUp 1s ease forwards;
    }

    section.content-section h2 {
      font-size: 2rem;
      font-weight: 700;
      color: var(--primary-color);
      margin-bottom: 20px;
      letter-spacing: 0.06em;
      text-transform: uppercase;
      text-align: center;
    }

    .section-description {
      font-size: 1.1rem;
      color: #2b3a58;
      margin-bottom: 30px;
      text-align: center;
      max-width: 850px;
      margin-left: auto;
      margin-right: auto;
      line-height: 1.6;
    }

    .category-title {
      font-size: 1.6rem;
      color: var(--primary-color);
      margin-top: 40px;
      margin-bottom: 20px;
      text-transform: uppercase;
      border-bottom: 2px solid var(--accent-color);
      padding-bottom: 8px;
    }

    .formula-card {
      background-color: white;
      border-radius: 12px;
      box-shadow: 0 4px 12px var(--shadow-color);
      padding: 20px 25px;
      margin-bottom: 25px;
      transition: box-shadow 0.3s ease;
    }

    .formula-card:hover {
      box-shadow: 0 8px 24px var(--shadow-color);
    }

    .formula-card h3 {
      font-weight: 700;
      color: var(--primary-color);
      font-size: 1.3rem;
      margin-bottom: 12px;
    }

    .formula-card code {
      display: inline-block;
      background-color: var(--accent-color);
      color: var(--nav-bg);
      padding: 8px 14px;
      border-radius: 8px;
      font-size: 1.1rem;
      font-family: 'Courier New', Courier, monospace;
      user-select: all;
      letter-spacing: 0.02em;
      white-space: nowrap;
      transition: all 0.4s ease-in-out;
    }

    .formula-card code:hover {
      background-color: #001f3f;
      color: white;
      font-weight: bold;
      transform: scale(1.05) rotate(-1deg);
      box-shadow: 0 0 20px rgba(0, 31, 63, 0.4);
    }

    .formula-card p {
      margin-top: 10px;
      font-size: 1rem;
      color: #2b3a58;
      line-height: 1.5;
    }

    .formula-card p strong {
      color: var(--primary-color);
    }

    @keyframes fadeInUp {
      from {
        opacity: 0;
        transform: translateY(10px);
      }
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    @media (max-width: 768px) {
      h1 {
        font-size: 2.3rem;
      }
      section.content-section h2 {
        font-size: 1.7rem;
      }
      .formula-card h3 {
        font-size: 1.1rem;
      }
      .formula-card code {
        font-size: 1rem;
        white-space: normal;
      }
    }