.buc {
    --buc-accent: #3b82f6;
    --buc-accent-dark: #2563eb;
    --buc-bg: #fff;
    --buc-border: #e2e8f0;
    --buc-divider: rgba(226, 232, 240, 0.8);
    --buc-text: #0f172a;
    --buc-muted: #64748b;
    --buc-input-bg: #f1f5f9;
    --buc-header-bg: linear-gradient(135deg, rgba(59,130,246,0.12) 0%, rgba(37,99,235,0.04) 100%);
    --buc-low:    #64748b;
    --buc-normal: #10b981;
    --buc-border-c: #f59e0b;
    --buc-high:   #ef4444;

    max-width: 900px;
    margin: 0 auto;
    padding: 1rem;
  }

  
  .buc__card {
    background: var(--buc-bg);
    border: 1px solid var(--buc-border);
    border-radius: 2.5rem;
    box-shadow: 0 25px 50px rgba(0,0,0,0.08);
    overflow: hidden;
  }

  .buc__icon-cache { display: none; }

  
  .buc__section {
    padding: 2.5rem;
  }

  .buc__section--bordered {
    border-top: 1px solid var(--buc-divider);
  }

  .buc__section-title {
    display: block;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--buc-muted);
    margin-bottom: 1.5rem;
  }

  
  .buc__header {
    padding: 2.5rem;
    background: var(--buc-header-bg);
    border-bottom: 1px solid var(--buc-divider);
    display: flex;
    align-items: center;
    gap: 1.5rem;
  }

  .buc__header-icon {
    color: var(--buc-accent);
    width: 3rem;
    height: 3rem;
    flex-shrink: 0;
  }

  .buc__header-icon svg { width: 100%; height: 100%; display: block; }

  .buc__header-title {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--buc-text);
    margin: 0;
  }

  .buc__header-sub {
    font-size: 0.9rem;
    color: var(--buc-muted);
    margin: 0.2rem 0 0;
  }

  
  .buc__analyte-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
    gap: 0.875rem;
  }

  .buc__analyte {
    background: var(--buc-bg);
    border: 1px solid var(--buc-border);
    border-radius: 1.25rem;
    padding: 1rem 0.75rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.45rem;
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--buc-text);
  }

  .buc__analyte:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.08);
    border-color: var(--buc-accent);
  }

  .buc__analyte--active {
    background: var(--buc-accent);
    border-color: var(--buc-accent);
    color: #fff;
    box-shadow: 0 8px 20px rgba(59,130,246,0.3);
  }

  .buc__analyte-icon {
    width: 1.75rem;
    height: 1.75rem;
  }

  .buc__analyte-icon svg { width: 100%; height: 100%; display: block; }

  .buc__analyte-label {
    font-size: 0.75rem;
    font-weight: 700;
    text-align: center;
    line-height: 1.2;
  }

  
  .buc__converter {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    gap: 1.25rem;
    margin-bottom: 2rem;
  }

  .buc__input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
  }

  .buc__input-label {
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--buc-muted);
  }

  .buc__input-wrap {
    position: relative;
    display: flex;
    align-items: center;
  }

  .buc__input {
    width: 100%;
    background: var(--buc-input-bg);
    border: 2px solid transparent;
    border-radius: 1rem;
    padding: 1rem 4.5rem 1rem 1.1rem;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--buc-text);
    outline: none;
    transition: all 0.2s ease;
    box-sizing: border-box;
  }

  .buc__input:focus {
    background: var(--buc-bg);
    border-color: var(--buc-accent);
    box-shadow: 0 0 0 3px rgba(59,130,246,0.12);
  }

  .buc__input::-webkit-inner-spin-button,
  .buc__input::-webkit-outer-spin-button { -webkit-appearance: none; }
  .buc__input[type="number"] { -moz-appearance: textfield; }

  .buc__unit-tag {
    position: absolute;
    right: 0.875rem;
    font-size: 0.68rem;
    font-weight: 800;
    color: var(--buc-muted);
    background: var(--buc-bg);
    padding: 0.2rem 0.45rem;
    border-radius: 0.4rem;
    border: 1px solid var(--buc-border);
    pointer-events: none;
  }

  .buc__swap {
    width: 3.25rem;
    height: 3.25rem;
    border-radius: 50%;
    background: var(--buc-input-bg);
    border: 1px solid var(--buc-border);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--buc-text);
    transition: all 0.3s ease;
    flex-shrink: 0;
  }

  .buc__swap:hover, .buc__swap--active {
    background: var(--buc-accent);
    border-color: var(--buc-accent);
    color: #fff;
  }

  .buc__swap:hover { transform: rotate(180deg); }

  .buc__swap-icon {
    width: 1.4rem;
    height: 1.4rem;
  }

  .buc__swap-icon svg { width: 100%; height: 100%; display: block; }

  .buc__swap-icon--v { display: none; }

  
  .buc__gauge-track {
    height: 14px;
    background: var(--buc-input-bg);
    border-radius: 7px;
    display: flex;
    position: relative;
    overflow: visible;
    margin-bottom: 1.5rem;
  }

  .buc__gauge-seg {
    height: 100%;
    flex: 1;
  }

  .buc__gauge-seg--low    { background: var(--buc-low);      border-radius: 7px 0 0 7px; }
  .buc__gauge-seg--normal { background: var(--buc-normal); }
  .buc__gauge-seg--border { background: var(--buc-border-c); }
  .buc__gauge-seg--high   { background: var(--buc-high);     border-radius: 0 7px 7px 0; }

  .buc__gauge-marker {
    position: absolute;
    top: -8px;
    left: 0%;
    width: 30px;
    height: 30px;
    background: var(--buc-bg);
    border: 5px solid var(--buc-accent);
    border-radius: 50%;
    transform: translateX(-50%);
    transition: left 0.55s cubic-bezier(0.34, 1.56, 0.64, 1);
    z-index: 2;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
  }

  .buc__gauge-status {
    text-align: center;
    min-height: 2rem;
  }

  .buc__status-text {
    font-size: 1.2rem;
    font-weight: 800;
    color: var(--buc-muted);
    transition: color 0.3s ease;
  }

  .buc .buc__status--low    { color: var(--buc-low); }
  .buc .buc__status--normal { color: var(--buc-normal); }
  .buc .buc__status--border { color: var(--buc-border-c); }
  .buc .buc__status--high   { color: var(--buc-high); }

  
  .buc__history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
  }

  .buc__history-header .buc__section-title { margin-bottom: 0; }

  .buc__btn-add {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(59,130,246,0.1);
    color: var(--buc-accent);
    border: none;
    padding: 0.625rem 1.25rem;
    border-radius: 0.875rem;
    font-weight: 800;
    font-size: 0.875rem;
    cursor: pointer;
    transition: all 0.2s ease;
  }

  .buc__btn-add:hover {
    background: rgba(59,130,246,0.18);
    transform: translateY(-1px);
  }

  .buc__btn-icon {
    width: 1.1rem;
    height: 1.1rem;
  }

  .buc__btn-icon svg { width: 100%; height: 100%; display: block; }

  .buc__table-wrap {
    overflow-x: auto;
    border-radius: 1rem;
    border: 1px solid var(--buc-border);
  }

  .buc__table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
    min-width: 520px;
  }

  .buc__table thead th {
    padding: 1rem 1.25rem;
    font-size: 0.72rem;
    text-transform: uppercase;
    font-weight: 800;
    color: var(--buc-muted);
    background: rgba(0,0,0,0.02);
    border-bottom: 2px solid var(--buc-border);
  }

  .buc__table tbody td {
    padding: 1rem 1.25rem;
    font-size: 0.95rem;
    font-weight: 600;
    border-bottom: 1px solid var(--buc-border);
    color: var(--buc-text);
  }

  .buc__table tbody tr:last-child td { border-bottom: none; }

  .buc__empty-row td {
    text-align: center;
    padding: 3rem;
    color: var(--buc-muted);
    font-style: italic;
    font-weight: 400;
  }

  
  .buc__row-status {
    font-size: 0.8rem;
    font-weight: 700;
    padding: 0.25rem 0.75rem;
    border-radius: 2rem;
    display: inline-block;
  }

  .buc__row-status--low    { background: rgba(100,116,139,0.12); color: var(--buc-low); }
  .buc__row-status--normal { background: rgba(16,185,129,0.12);  color: var(--buc-normal); }
  .buc__row-status--border { background: rgba(245,158,11,0.12);  color: var(--buc-border-c); }
  .buc__row-status--high   { background: rgba(239,68,68,0.12);   color: var(--buc-high); }

  .buc__row-delete {
    background: rgba(239,68,68,0.08);
    border: none;
    width: 2rem;
    height: 2rem;
    border-radius: 0.5rem;
    cursor: pointer;
    color: var(--buc-high);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    padding: 0;
  }

  .buc__row-delete svg { width: 1.1rem; height: 1.1rem; display: block; }

  .buc__row-delete:hover {
    background: var(--buc-high);
    color: #fff;
  }

  
  .buc__footer {
    padding: 1.5rem 2.5rem;
    background: rgba(0,0,0,0.02);
    border-top: 1px solid var(--buc-divider);
    display: flex;
    gap: 1rem;
    align-items: flex-start;
  }

  .buc__footer-icon {
    color: var(--buc-accent);
    width: 1.4rem;
    height: 1.4rem;
    flex-shrink: 0;
    margin-top: 0.1rem;
  }

  .buc__footer-icon svg { width: 100%; height: 100%; display: block; }

  .buc__footer-text {
    font-size: 0.82rem;
    line-height: 1.6;
    color: var(--buc-muted);
    margin: 0;
  }

  
  .theme-dark .buc {
    --buc-bg: #0f172a;
    --buc-border: #1e293b;
    --buc-divider: rgba(30,41,59,0.9);
    --buc-text: #f8fafc;
    --buc-muted: #94a3b8;
    --buc-input-bg: #1e293b;
    --buc-header-bg: linear-gradient(135deg, rgba(59,130,246,0.12) 0%, rgba(15,23,42,0.5) 100%);
  }

  .theme-dark .buc__analyte {
    background: #1e293b;
    border-color: #334155;
  }

  .theme-dark .buc__unit-tag {
    background: #0f172a;
    border-color: #334155;
  }

  .theme-dark .buc__input:focus {
    background: #1e293b;
  }

  .theme-dark .buc__table thead th {
    background: rgba(255,255,255,0.02);
  }

  .theme-dark .buc__footer {
    background: rgba(255,255,255,0.02);
  }

  
  @media (max-width: 768px) {
    .buc__section { padding: 1.75rem 1.25rem; }
    .buc__header   { padding: 1.75rem 1.25rem; }
    .buc__footer   { padding: 1.25rem; }

    .buc__converter {
      grid-template-columns: 1fr;
      gap: 1.25rem;
    }

    .buc__swap {
      justify-self: center;
    }

    .buc__swap-icon--h { display: none; }
    .buc__swap-icon--v { display: block; }

    .buc__input { font-size: 1.25rem; }
  }