:root {
  --accent: #00AE42;
  --accent-hover: #008f36;
  --bg-color: #f9f9f9;
  --text-color: #333333;
  --card-bg: #ffffff;
}

/* --- NEW: System Dark Mode Detection --- */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --card-bg: #1e1e1e;
  }
  
  /* Make header shadow visible in dark mode */
  header {
    box-shadow: 0 2px 10px rgba(0,0,0,0.5) !important;
  }
  
  /* Make input fields dark */
  .form-group input, .form-group textarea {
    background-color: #2a2a2a;
    color: #e0e0e0;
    border: 1px solid #444 !important;
  }
}
/* --------------------------------------- */

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; }

body { background-color: var(--bg-color); color: var(--text-color); line-height: 1.6; transition: background-color 0.3s, color 0.3s; }

/* Navigation */
header { background-color: var(--card-bg); padding: 1rem 5%; box-shadow: 0 2px 5px rgba(0,0,0,0.05); display: flex; justify-content: space-between; align-items: center; transition: background-color 0.3s; }
header h1 a { color: var(--accent); text-decoration: none; font-weight: bold; }
nav a { text-decoration: none; color: var(--text-color); margin-left: 20px; font-weight: 500; transition: color 0.3s; }
nav a:hover { color: var(--accent); }

/* Buttons */
.btn { display: inline-block; background-color: var(--accent); color: white; padding: 10px 20px; text-decoration: none; border-radius: 5px; font-weight: bold; transition: background 0.3s; border: none; cursor: pointer; text-align: center; }
.btn:hover { background-color: var(--accent-hover); }

/* Layouts */
main { padding: 2rem 5%; max-width: 1200px; margin: 0 auto; }
.hero { text-align: center; padding: 4rem 0; }
.hero h2 { font-size: 2.5rem; margin-bottom: 1rem; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 20px; margin-top: 2rem; }

/* Cards */
.card { background: var(--card-bg); border-radius: 8px; overflow: hidden; box-shadow: 0 4px 6px rgba(0,0,0,0.05); transition: transform 0.2s, background-color 0.3s; text-align: center; padding-bottom: 15px; }
.card:hover { transform: translateY(-5px); }
.card img { width: 100%; height: 250px; object-fit: cover; }
.card h3 { margin: 10px 0; }
.card .price { color: var(--accent); font-weight: bold; font-size: 1.2rem; }

/* Single Item Page */
.item-detail { display: flex; gap: 40px; flex-wrap: wrap; background: var(--card-bg); padding: 2rem; border-radius: 8px; transition: background-color 0.3s; }
.item-detail img { max-width: 400px; width: 100%; border-radius: 8px; }
.item-info { flex: 1; min-width: 300px; }
.item-info h2 { font-size: 2rem; margin-bottom: 10px; }
.item-info .price { font-size: 1.5rem; color: var(--accent); font-weight: bold; margin-bottom: 20px; }

/* Forms */
form { background: var(--card-bg); padding: 2rem; border-radius: 8px; max-width: 600px; margin: 0 auto; transition: background-color 0.3s; }
.form-group { margin-bottom: 15px; }
.form-group label { display: block; margin-bottom: 5px; font-weight: bold; }
.form-group input, .form-group textarea { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 5px; transition: background-color 0.3s, color 0.3s; }