:root {
  --color-bg-gradient-start: #f8fafc;
  --color-bg-gradient-end: #e2e8f0;
  --color-bg-container: #fff;
  --color-border: #e2e8f0;
  --color-shadow: rgba(0,0,0,0.10);
  --color-shadow-light: rgba(0,0,0,0.04);
  --color-shadow-hover: rgba(34, 34, 59, 0.09);
  --color-primary: #228be6;
  --color-primary-bg: #e7f5ff;
  --color-link: #2274a5;
  --color-link-hover: #10506b;
  --color-title: #22223b;
  --color-text: #495057;
  --color-note: #adb5bd;
  --color-desc: #868e96;
  --color-block-bg: #f8fafc;
  --color-block-border: #bcdffb;
  --color-block-title: #228be6;
  --color-prod-strong: #495057;
  --color-prod-link: #2274a5;
  --color-prod-link-hover: #10506b;
  --font-main: 'Montserrat', Arial, sans-serif;
}

body {
    background: linear-gradient(120deg, var(--color-bg-gradient-start) 0%, var(--color-bg-gradient-end) 100%);
    font-family: var(--font-main);
    min-height: 100vh;
    margin: 0;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
  }
  .container {
    max-width: 480px;
    background: var(--color-bg-container);
    border-radius: 2rem;
    box-shadow: 0 6px 30px var(--color-shadow);
    padding: 2.5rem 1.5rem;
    margin: 2rem;
    text-align: center;
    animation: fadeIn 1s;
  }
  @keyframes fadeIn {
    from {opacity: 0; transform: translateY(30px);}
    to {opacity: 1; transform: translateY(0);}
  }
  .avatar {
    width: 108px;
    height: 108px;
    object-fit: cover;
    border-radius: 100%;
    border: 5px solid var(--color-border);
    margin-bottom: 1rem;
    box-shadow: 0 2px 12px var(--color-shadow);
  }
  h1 {
    font-size: 2rem;
    font-weight: 700;
    margin: 0 0 .25rem 0;
    color: var(--color-title);
  }
  .slogan {
    color: var(--color-text);
    font-size: 1rem;
    margin-bottom: .6rem;
  }
  .note {
    color: var(--color-note);
    font-size: .95rem;
    margin-bottom: 1.5rem;
  }
  .biz-block {
    background: var(--color-block-bg);
    border-radius: 1.2rem;
    box-shadow: 0 1px 8px var(--color-shadow-light);
    margin-top: 2.1rem;
    margin-bottom: 1.2rem;
    padding: 1.4rem 1rem 1.1rem 1rem;
    text-align: left;
    border-left: 6px solid var(--color-block-border);
  }
  .biz-block h2 {
    font-size: 1.19rem;
    font-weight: 700;
    margin: 0 0 0.8rem 0;
    color: var(--color-block-title);
    letter-spacing: 0.01em;
    display: flex;
    align-items: center;
    gap: 0.5em;
  }
  .links {
    display: flex;
    flex-direction: column;
    gap: 1.1rem;
    margin-bottom: 0.5rem;
  }
  .link-card {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.2rem 1.1rem;
    background: var(--color-bg-container);
    border-radius: 1rem;
    box-shadow: 0 1px 7px var(--color-shadow-light);
    text-decoration: none;
    color: var(--color-title);
    font-weight: 500;
    font-size: 1.08rem;
    transition: transform .12s, box-shadow .12s, background .15s;
    border: 1px solid #e9ecef;
    margin-bottom: .5rem;
  }
  .link-card:hover {
    transform: translateY(-2px) scale(1.025);
    box-shadow: 0 4px 20px var(--color-shadow-hover);
    background: #edf2fb;
  }
  .link-card:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    box-shadow: 0 0 0 4px var(--color-primary-bg);
    background: var(--color-primary-bg);
  }
  .link-icon {
    font-size: 1.5em;
    color: var(--color-primary);
    background: var(--color-primary-bg);
    border-radius: 50%;
    width: 2.2em;
    height: 2.2em;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: .5rem;
  }
  .desc {
    color: var(--color-desc);
    font-size: .97rem;
    margin-top: .1rem;
    text-align: left;
  }
  .prod-list {
    margin-left: 2rem;
    margin-bottom: .5rem;
  }
  .prod-list strong {
    display: block;
    color: var(--color-prod-strong);
    margin-bottom: .2rem;
  }
  .prod-list ul {
    padding-left: 1.1em;
    margin: .2em 0;
  }
  .prod-list li {
    font-size: .97em;
    margin-bottom: .1em;
  }
  .prod-list li a {
    color: var(--color-prod-link);
    text-decoration: underline dotted;
    transition: color 0.15s;
  }
  .prod-list li a:hover {
    color: var(--color-prod-link-hover);
  }
  @media (max-width: 520px) {
    .container {padding: 1.1rem;}
    .link-card {font-size: 1rem; padding: 1rem;}
    .avatar {width: 80px; height: 80px;}
    .biz-block {padding: 1rem 0.4rem;}
  }
  @media (max-width: 900px) {
    .container {
      max-width: 95vw;
      padding: 1.5rem 0.7rem;
      margin: 1.2rem;
    }
    h1 {
      font-size: 1.5rem;
    }
    .avatar {
      width: 90px;
      height: 90px;
    }
    .link-card {
      font-size: 1.01rem;
      padding: 1rem 0.7rem;
    }
    .biz-block {
      padding: 1.1rem 0.6rem;
    }
  }
  @media (prefers-color-scheme: dark) {
    :root {
      --color-bg-gradient-start: #232946;
      --color-bg-gradient-end: #121629;
      --color-bg-container: #181a2a;
      --color-border: #232946;
      --color-shadow: rgba(0,0,0,0.35);
      --color-shadow-light: rgba(0,0,0,0.12);
      --color-shadow-hover: rgba(238, 187, 195, 0.09);
      --color-primary: #eebbc3;
      --color-primary-bg: #232946;
      --color-link: #b8c1ec;
      --color-link-hover: #eebbc3;
      --color-title: #eebbc3;
      --color-text: #b8c1ec;
      --color-note: #a1a1aa;
      --color-desc: #b8c1ec;
      --color-block-bg: #232946;
      --color-block-border: #b8c1ec;
      --color-block-title: #eebbc3;
      --color-prod-strong: #eebbc3;
      --color-prod-link: #b8c1ec;
      --color-prod-link-hover: #eebbc3;
    }
    body {
      background: linear-gradient(120deg, var(--color-bg-gradient-start) 0%, var(--color-bg-gradient-end) 100%);
      color: #f4f4f4;
    }
    .container {
      background: var(--color-bg-container);
      box-shadow: 0 6px 30px var(--color-shadow);
    }
    .avatar {
      border: 5px solid var(--color-border);
      box-shadow: 0 2px 12px var(--color-shadow);
    }
    h1 {
      color: var(--color-title);
    }
    .slogan {
      color: var(--color-text);
    }
    .note {
      color: var(--color-note);
    }
    .biz-block {
      background: var(--color-block-bg);
      border-left: 6px solid var(--color-block-border);
      box-shadow: 0 1px 8px var(--color-shadow-light);
    }
    .biz-block h2 {
      color: var(--color-block-title);
    }
    .links {
      /* giữ nguyên */
    }
    .link-card {
      background: var(--color-bg-container);
      color: var(--color-title);
      box-shadow: 0 1px 7px var(--color-shadow-light);
      border: 1px solid #e9ecef;
    }
    .link-card:hover, .link-card:focus {
      background: #edf2fb;
    }
    .link-icon {
      color: var(--color-primary);
      background: var(--color-primary-bg);
    }
    .desc {
      color: var(--color-desc);
    }
    .prod-list strong {
      color: var(--color-prod-strong);
    }
    .prod-list li a {
      color: var(--color-prod-link);
    }
    .prod-list li a:hover {
      color: var(--color-prod-link-hover);
    }
  }
  .prod-list-featured {
    background: var(--color-block-bg);
    border-radius: 0.8rem;
    box-shadow: 0 1px 6px var(--color-shadow-light);
    margin: 0.7rem 0 0.5rem 0;
    padding: 0.7rem 0.7rem 0.5rem 0.7rem;
    text-align: left;
    border-left: 4px solid var(--color-block-border);
  }
  .prod-list-featured strong {
    color: var(--color-block-title);
    font-size: 1.01rem;
    display: block;
    margin-bottom: 0.3rem;
  }
  .prod-list-featured ul {
    list-style: disc inside;
    margin: 0.1em 0 0.2em 0.5em;
    padding: 0;
  }
  .prod-item {
    font-size: 0.98em;
    margin-bottom: 0.15em;
    cursor: pointer;
    transition: color 0.18s, opacity 0.18s, text-decoration 0.18s;
  }
  .prod-item a {
    color: var(--color-link);
    text-decoration: underline dotted;
    transition: color 0.15s;
  }
  .prod-item a:hover {
    color: var(--color-link-hover);
  }
  .prod-item-hidden {
    opacity: 0.4;
    text-decoration: line-through wavy #adb5bd;
    /* pointer-events: none; */
  }
  .prod-note {
    color: var(--color-note);
    font-size: 0.93em;
    margin-top: 0.2em;
    font-style: italic;
  }
  .prod-list-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.2rem;
  }
  .prod-toggle-btn {
    background: none;
    border: none;
    font-size: 1.1em;
    cursor: pointer;
    color: var(--color-block-title);
    padding: 0.1em 0.3em;
    border-radius: 0.4em;
    transition: background 0.15s;
  }
  .prod-toggle-btn:hover, .prod-toggle-btn:focus {
    background: var(--color-primary-bg);
    outline: 2px solid var(--color-primary);
  }
  .prod-list-content {
    transition: max-height 0.25s cubic-bezier(0.4,0,0.2,1), opacity 0.2s;
    overflow: hidden;
    max-height: 500px;
    opacity: 1;
  }
  .prod-list-hidden {
    max-height: 0 !important;
    opacity: 0.1;
    pointer-events: none;
  }
  .link-card-small {
    font-size: 0.93em;
    padding: 0.7rem 0.8rem;
    margin-left: 2.2em;
    background: var(--color-bg-container);
    border: 1px dashed #e9ecef;
    box-shadow: none;
    margin-bottom: 0.3rem;
  }
  .link-card-small .link-icon {
    font-size: 1.2em;
    width: 1.7em;
    height: 1.7em;
    margin-right: .4rem;
  }
  .wechat-qr-block {
    display: flex;
    align-items: center;
    gap: 0.7em;
    margin: 0.5em 0 0.2em 0;
  }
  .wechat-qr-label {
    color: var(--color-block-title);
    font-size: 0.98em;
    font-weight: 500;
  }
  .wechat-qr-img {
    width: 64px;
    height: 64px;
    border-radius: 0.5em;
    border: 1.5px solid #e2e8f0;
    object-fit: cover;
    box-shadow: 0 1px 6px var(--color-shadow-light);
  }