@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;600&display=swap');

    * {margin:0;padding:0;box-sizing:border-box;font-family:'Poppins',sans-serif;}
    body {background:#F5F7FA;color:#333;}

    /* HEADER */
    header {
      background:#fff;
      display:flex;
      justify-content:space-between;
      align-items:center;
      padding:15px 50px;
      box-shadow:0 2px 5px rgba(0,0,0,0.1);
    }
    header img {height:50px;}
    nav a {
      margin-left:20px;
      color:#2F3E9E;
      text-decoration:none;
      font-weight:500;
    }
    nav a:hover {color:#E53935;}

    /* CONTAINER */
    .container {
      padding:60px 50px;
    }

    .product-detail {
      display:grid;
      grid-template-columns:1fr 1fr;
      gap:40px;
      background:#fff;
      padding:30px;
      border-radius:10px;
      box-shadow:0 2px 8px rgba(0,0,0,0.05);
    }

    .product-images {
    text-align: center;
    }

    #mainImage {
    width: 100%;
    max-height: 300px;
    object-fit: contain;
    border-radius: 10px;
    margin-bottom: 15px;
    transition: 0.3s;
    }
    #mainImage:hover {
    transform: scale(1.05);
    }

    .thumbnail-list {
        width: 100%;
    display: inline-flex;
    justify-content: center;
    gap: 10px;
    flex-wrap: wrap;
    }

    .thumbnail-list img {
    width: 70px;
    height: 70px;
    object-fit: contain;
    border-radius: 6px;
    cursor: pointer;
    border: 2px solid transparent;
    transition: 0.3s;
    }

    .thumbnail-list img:hover {
    transform: scale(1.05);
    }

    .thumbnail-list img.active {
    border: 2px solid #E53935;
    }

    .product-images img {

      border-radius:10px;
    }

    .product-info h1 {
      color:#2F3E9E;
      margin-bottom:15px;
    }

    .price {
      color:#E53935;
      font-size:24px;
      font-weight:600;
      margin-bottom:15px;
    }

    .desc {
      margin-bottom:20px;
      color:#555;
    }

    .btn-group a {
      padding:12px 25px;
      border:none;
      border-radius:6px;
      cursor:pointer;
      margin-right:10px;
      font-weight:500;
      text-decoration: none;
    }

    .btn-buy {
      background:#E53935;
      color:#fff;
    }
    .btn-buy:hover {background:#c62828;}

    .btn-contact {
      background:#2F3E9E;
      color:#fff;
    }

    /* SECTION */
    .section {
      margin-top:50px;
      background:#fff;
      padding:30px;
      border-radius:10px;
    }

    .section h2 {
      color:#2F3E9E;
      margin-bottom:20px;
    }

    ul {padding-left:20px;}

    /* RELATED */
    .related {
      display:grid;
      grid-template-columns:repeat(auto-fit,minmax(200px,1fr));
      gap:20px;
    }

    .card {
      background:#F5F7FA;
      padding:15px;
      border-radius:8px;
      text-align:center;
    }

    .card img {
      width:100%;
      height:120px;
      object-fit:contain;
    }

    footer {
      background:#2F3E9E;
      color:#fff;
      text-align:center;
      padding:30px;
      margin-top:50px;
    }

    @media(max-width:768px){
      .product-detail {grid-template-columns:1fr;}
    }

    /* ZALO BUTTON */
    .zalo-btn{
      position: fixed;
      bottom: 20px;
      right: 20px;
      background: #E53935;
      color: white;
      padding: 12px 18px;
      border-radius: 30px;
      text-decoration: none;
      box-shadow: 0 4px 10px rgba(0,0,0,0.2);
      z-index: 999;
      font-size:14px;
    }

    .zalo-btn:hover{
      background:#c62828;
    }
    @media(max-width:768px){

  header{
    flex-direction:column;
    padding:15px 20px;
  }

  nav{
    margin-top:10px;
  }

  nav a{
    margin:0 10px;
    font-size:13px;
  }

  .container{
    padding:30px 15px;
  }

  .product-detail{
    grid-template-columns:1fr;
    padding:20px;
  }

  .product-info h1{
    font-size:22px;
  }

  .price{
    font-size:20px;
  }

  .btn-group a{
    width:100%;
    margin-bottom:10px;
  }

  .related{
    grid-template-columns:1fr;
  }

  /* Software guide responsive */
  .sw-step-body {
    flex-direction: column !important;
  }

  .sw-step-img {
    max-width: 100% !important;
  }

}

/* =====================
   SOFTWARE GUIDE STYLES
   ===================== */

.software-guide {
  background: #fff;
  padding: 30px;
  border-radius: 10px;
  margin-top: 50px;
}

.software-guide h2 {
  color: #2F3E9E;
  margin-bottom: 10px;
}

.sw-intro {
  color: #555;
  margin-bottom: 30px;
  line-height: 1.7;
  border-left: 4px solid #2F3E9E;
  padding-left: 14px;
  background: #f0f4ff;
  padding: 12px 16px;
  border-radius: 0 6px 6px 0;
}

.sw-step {
  margin-bottom: 40px;
  border: 1px solid #e8ecf4;
  border-radius: 10px;
  overflow: hidden;
}

.sw-step-header {
  display: flex;
  align-items: center;
  gap: 14px;
  background: #2F3E9E;
  padding: 14px 20px;
}

.sw-step-num {
  background: #fff;
  color: #2F3E9E;
  font-weight: 700;
  font-size: 16px;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.sw-step-header h3 {
  color: #fff;
  font-size: 16px;
  margin: 0;
}

.sw-step-body {
  display: flex;
  gap: 24px;
  padding: 20px;
  align-items: flex-start;
}

.sw-step-text {
  flex: 1;
  line-height: 1.75;
  color: #333;
}

.sw-step-text p { margin-bottom: 10px; }
.sw-step-text ul, .sw-step-text ol {
  padding-left: 20px;
  margin-bottom: 10px;
}
.sw-step-text li { margin-bottom: 6px; }
.sw-step-text code {
  background: #f0f0f0;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: monospace;
  font-size: 13px;
}

.sw-step-img {
  max-width: 500px;
  flex-shrink: 0;
  text-align: center;
}

.sw-step-img img {
  width: 100%;
  border-radius: 8px;
  border: 1px solid #dde3f0;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  object-fit: contain;
}

.sw-img-caption {
  font-size: 12px;
  color: #888;
  margin-top: 6px;
  font-style: italic;
}

.sw-download-btn {
  display: inline-block;
  margin-top: 12px;
  padding: 10px 20px;
  background: #2F3E9E;
  color: #fff;
  border-radius: 6px;
  text-decoration: none;
  font-weight: 500;
  font-size: 14px;
  transition: background 0.2s;
}

.sw-download-btn:hover {
  background: #1a2c7e;
}

.sw-docs {
  margin-top: 30px;
  background: #f8f9fc;
  border-radius: 8px;
  padding: 20px 24px;
  border: 1px solid #e2e8f4;
}

.sw-docs h3 {
  color: #2F3E9E;
  margin-bottom: 12px;
  font-size: 15px;
}

.sw-docs ul {
  list-style: none;
  padding: 0;
}

.sw-docs li {
  margin-bottom: 8px;
}

.sw-docs a {
  color: #2F3E9E;
  text-decoration: none;
  font-size: 14px;
}

.sw-docs a:hover {
  text-decoration: underline;
}

/* Part headers (PHẦN I / PHẦN II) */
.sw-part-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 36px 0 8px;
  padding-bottom: 10px;
  border-bottom: 3px solid #2F3E9E;
}

.sw-part-label {
  background: #2F3E9E;
  color: #fff;
  font-weight: 700;
  font-size: 13px;
  padding: 4px 12px;
  border-radius: 4px;
  white-space: nowrap;
  letter-spacing: 0.5px;
}

.sw-part-header h3 {
  color: #2F3E9E;
  font-size: 17px;
  margin: 0;
}

.sw-part-desc {
  color: #555;
  margin-bottom: 20px;
  font-size: 14px;
  line-height: 1.7;
}

/* Note boxes */
.sw-note {
  border-radius: 6px;
  padding: 12px 14px;
  margin: 12px 0;
  font-size: 13.5px;
  line-height: 1.75;
}

.sw-note-blue {
  background: #eef3ff;
  border-left: 4px solid #2F3E9E;
}

.sw-note-green {
  background: #edfaf3;
  border-left: 4px solid #198754;
}

.sw-note-warning {
  background: #fff8ec;
  border-left: 4px solid #f0a500;
}

/* Badge inside step header */
.sw-badge {
  display: inline-block;
  background: rgba(255,255,255,0.25);
  color: #fff;
  font-size: 11px;
  font-weight: 500;
  padding: 2px 8px;
  border-radius: 20px;
  margin-left: 8px;
  vertical-align: middle;
  border: 1px solid rgba(255,255,255,0.5);
}