:root {
  --mau-chinh: #0f766e;
  --mau-chinh-dam: #0b5b55;
  --mau-nen: #f2fbf9;
  --mau-vien: #99f6e4;
  --mau-loi: #dc2626;
  --mau-thanhcong: #16a34a;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Segoe UI", Arial, sans-serif;
  background: var(--mau-nen);
  color: #1f2937;
  line-height: 1.6;
}
.site-header {
  background: var(--mau-chinh);
  color: #fff;
  padding: 1.2rem 1.6rem;
}
.site-header h1 { margin: 0 0 0.25rem; font-size: 1.4rem; }
.site-header p { margin: 0; opacity: 0.92; font-size: 0.95rem; }
.main-nav {
  background: #fff;
  border-bottom: 1px solid var(--mau-vien);
  padding: 0.75rem 1.6rem;
  display: flex;
  gap: 1rem;
}
.main-nav a {
  color: var(--mau-chinh);
  text-decoration: none;
  font-weight: 600;
  padding: 0.3rem 0.6rem;
  border-radius: 0.3rem;
}
.main-nav a:hover, .main-nav a.active {
  background: var(--mau-chinh);
  color: #fff;
}
.site-footer {
  text-align: center;
  padding: 1.5rem;
  color: #6b7280;
  font-size: 0.85rem;
  border-top: 1px solid var(--mau-vien);
  margin-top: 2rem;
  background: #fff;
}
.site-footer a { color: var(--mau-chinh); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }

    .khung-giao-dien-danh-ba {
      display: flex;
      flex-wrap: wrap;
      gap: 1.5rem;
      max-width: 1100px;
      margin: 1.5rem auto;
      padding: 0 1rem;
    }
    .thanh-ben-danh-ba {
      flex: 1 1 340px;
      display: flex;
      flex-direction: column;
      gap: 1.4rem;
    }
    .vung-chinh-danh-ba {
      flex: 2 1 520px;
    }
    section {
      background: #fff;
      border: 1px solid var(--mau-vien);
      border-radius: 0.6rem;
      padding: 1.2rem 1.4rem;
    }
    section h2 {
      margin-top: 0;
      color: var(--mau-chinh-dam);
      font-size: 1.15rem;
    }
    .nhom-so-danh-ba {
      border: 1px solid var(--mau-vien);
      border-radius: 0.5rem;
      padding: 0.9rem 1rem;
      margin: 0;
    }
    .nhom-so-danh-ba legend {
      font-weight: bold;
      color: var(--mau-chinh-dam);
      padding: 0 0.4rem;
    }
    .muc-nhap-danh-ba {
      display: flex;
      flex-direction: column;
      margin-bottom: 0.8rem;
    }
    .nhan-muc-danh-ba {
      margin-bottom: 0.25rem;
      font-weight: 600;
      font-size: 0.9rem;
    }
    .o-nhap-danh-ba {
      padding: 0.5rem 0.65rem;
      border: 1px solid #94a3b8;
      border-radius: 0.35rem;
      font: inherit;
    }
    .o-nhap-danh-ba:focus {
      outline: none;
      border-color: var(--mau-chinh);
      box-shadow: 0 0 0 3px rgba(15, 118, 110, 0.18);
    }
    .loi-nhap-danh-ba {
      color: var(--mau-loi);
      font-size: 0.82rem;
      margin-top: 0.25rem;
      min-height: 1.1rem;
    }
    .muc-danh-ba-loi .o-nhap-danh-ba {
      border-color: var(--mau-loi);
    }
    .nut-ghi-danh-ba {
      background: var(--mau-chinh);
      color: #fff;
      border: none;
      padding: 0.6rem 1.2rem;
      border-radius: 0.4rem;
      cursor: pointer;
      font-weight: 600;
      font-size: 0.95rem;
      width: 100%;
    }
    .nut-ghi-danh-ba:hover { background: var(--mau-chinh-dam); }
    .nut-xoa-lien-he {
      background: #fee2e2;
      color: #991b1b;
      border: 1px solid #fca5a5;
      padding: 0.3rem 0.7rem;
      border-radius: 0.3rem;
      cursor: pointer;
      font-size: 0.85rem;
      font-weight: 600;
    }
    .nut-xoa-lien-he:hover { background: #fecaca; }
    .hop-tin-danh-ba {
      border-radius: 0.5rem;
      padding: 0.8rem 1rem;
      margin-top: 0.8rem;
    }
    .hop-bao-thanh-cong {
      background: #ecfdf5;
      border: 1px solid var(--mau-thanhcong);
      color: #065f46;
    }
    .hop-tin-danh-ba[hidden] { display: none; }
    .so-luu-tru-danh-ba {
      width: 100%;
      border-collapse: collapse;
      font-size: 0.92rem;
    }
    .so-luu-tru-danh-ba th, .so-luu-tru-danh-ba td {
      border: 1px solid var(--mau-vien);
      padding: 0.55rem 0.75rem;
      text-align: left;
    }
    .so-luu-tru-danh-ba th {
      background: var(--mau-chinh);
      color: #fff;
    }
    .nhan-nhom-lien-he {
      display: inline-block;
      padding: 0.2rem 0.55rem;
      border-radius: 0.3rem;
      background: #ccfbf1;
      color: #0f766e;
      font-size: 0.8rem;
      font-weight: 600;
    }
    .the-chi-so-danh-ba {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0.6rem 0.8rem;
      background: #f0fdfa;
      border: 1px solid var(--mau-vien);
      border-radius: 0.4rem;
      margin-bottom: 0.5rem;
    }
    .so-kpi { font-size: 1.25rem; font-weight: bold; color: var(--mau-chinh-dam); }