/* === Root Variables === */
:root {
    --neon-green: #39ff14;
    --white: #ffffff;
    --dark-bg: #000000;
    --grid-line: rgba(255, 255, 255, 0.05);
    --neon-glow: 0 0 4px var(--neon-green), 0 0 8px var(--neon-green);
  }
  
  /* === Base === */
  html, body {
    margin: 0;
    padding: 0;
    background-color: var(--dark-bg);
    font-family: 'Inter', sans-serif;
    color: var(--white);
    line-height: 1.6;
    background-image:
      linear-gradient(var(--grid-line) 1px, transparent 1px),
      linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
    background-size: 40px 40px;
    background-attachment: fixed;
  }
  
  body {
    padding: 1rem;
  }
  
  /* === Text Elements === */
  h1, h2, h3, h4, h5, h6 {
    color: var(--neon-green);
    text-shadow: var(--neon-glow);
    margin-top: 1.5rem;
    margin-bottom: 1rem;
  }
  
  p {
    margin-bottom: 1rem;
  }
  
  a {
    color: var(--neon-green);
    text-decoration: none;
    text-shadow: var(--neon-glow);
  }
  
  a:hover {
    text-decoration: underline;
  }
  
  /* === Layout === */
  header, footer {
    border-bottom: 1px solid var(--grid-line);
    background-color: transparent;
    width: 100%;
  }
  
  footer {
    border-top: 1px solid var(--grid-line);
    border-bottom: none;
    margin-top: 3rem;
  }
  
  /* === Header & Footer Content Wrapper === */
  header > div, footer > div {
    max-width: 1100px;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
  }
  
  /* === Footer Grid Items === */
  footer > div > div {
    flex: 1 1 200px;
    min-width: 200px;
  }
  
  /* === Buttons === */
  button, input[type="submit"], input[type="button"] {
    background-color: var(--neon-green);
    color: #000;
    font-weight: bold;
    padding: 0.6rem 1rem;
    border: none;
    border-radius: 4px;
    box-shadow: var(--neon-glow);
    cursor: pointer;
    transition: transform 0.2s ease;
  }
  
  button:hover, input[type="submit"]:hover {
    transform: scale(1.05);
  }
  
  /* === Forms === */
  input, textarea, select {
    background-color: #111;
    color: var(--white);
    border: 1px solid var(--neon-green);
    padding: 0.5rem;
    margin-bottom: 1rem;
    border-radius: 4px;
    width: 100%;
    box-sizing: border-box;
  }
  
  /* === Images === */
  img {
    max-width: 100%;
    height: auto;
    display: block;
    border-radius: 6px;
    box-shadow: 0 0 8px #000;
  }
  
  /* === Lists === */
  ul {
    list-style: none;
    padding-left: 0;
    margin: 0;
  }
  
  li {
    margin: 0;
  }
  
  /* === Main Content === */
  main {
    max-width: 1100px;
    margin: 0 auto;
    padding: 1rem;
  }
  
  /* === Product Grid === */
  ul.product-list {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
    margin-top: 2rem;
    padding: 0;
  }
  
  li.product-item {
    background-color: #111;
    border: 1px solid var(--grid-line);
    padding: 1rem;
    border-radius: 8px;
    transition: transform 0.2s ease;
  }
  
  li.product-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 0 12px var(--neon-green);
  }
  
  /* === Responsive Typography === */
  h1 {
    font-size: 2rem;
  }
  h2 {
    font-size: 1.6rem;
  }
  h3 {
    font-size: 1.3rem;
  }
  
  /* === Mobile Tweaks === */
  @media (max-width: 768px) {
    body {
      padding: 0.75rem;
    }
  
    h1 {
      font-size: 1.6rem;
    }
  
    header > div, footer > div {
      flex-direction: column;
      align-items: flex-start;
    }
  
    ul.product-list {
      grid-template-columns: 1fr;
    }
  }