/* Cards */
    .card {
      border: 1px solid var(--border-color);
      border-radius: 14px;
      box-shadow: 0 2px 12px rgba(0,0,0,0.05);
    }
    .card-header {
      background: #fafbff;
      border-bottom: 1px solid var(--border-color);
      border-radius: 14px 14px 0 0 !important;
      padding: 14px 20px;
    }
    .card-header .card-title {
      font-family: 'Syne', sans-serif;
      font-size: 0.82rem;
      font-weight: 700;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      margin: 0;
    }
/* Checkerboard transparency preview */
    .checkerboard {
      background-image:
        linear-gradient(45deg, #ccc 25%, transparent 25%),
        linear-gradient(-45deg, #ccc 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #ccc 75%),
        linear-gradient(-45deg, transparent 75%, #ccc 75%);
      background-size: 14px 14px;
      background-position: 0 0, 0 7px, 7px -7px, -7px 0;
      background-color: #e8e8e8;
      border-radius: 10px;
      height: 110px;
      position: relative;
      overflow: hidden;
    }
    .checkerboard-overlay {
      position: absolute;
      inset: 0;
      border-radius: 10px;
      transition: background 0.1s ease;
    }

    /* Slider channel labels */
    .channel-label {
      font-size: 0.73rem;
      font-weight: 600;
      text-transform: uppercase;
      letter-spacing: 0.1em;
    }
    .channel-value {
      font-size: 0.78rem;
      min-width: 34px;
      text-align: right;
      color: #6c757d;
    }

    /* ── Colored slider tracks (overrides Bootstrap form-range) ── */
    input[type="range"].range-red,
    input[type="range"].range-green,
    input[type="range"].range-blue,
    input[type="range"].range-alpha {
      -webkit-appearance: none;
      appearance: none;
      height: 6px;
      border-radius: 4px;
      outline: none;
      cursor: pointer;
    }

    /* WebKit / Blink (Chrome, Edge, Safari) — runnable-track */
    input[type="range"].range-red::-webkit-slider-runnable-track {
      height: 6px; border-radius: 4px;
      background: linear-gradient(to right, #ffd0d0, #e53e3e);
    }
    input[type="range"].range-green::-webkit-slider-runnable-track {
      height: 6px; border-radius: 4px;
      background: linear-gradient(to right, #d0f5d0, #1a9e4e);
    }
    input[type="range"].range-blue::-webkit-slider-runnable-track {
      height: 6px; border-radius: 4px;
      background: linear-gradient(to right, #d0d8ff, #3b5bdb);
    }
    input[type="range"].range-alpha::-webkit-slider-runnable-track {
      height: 6px; border-radius: 4px;
      background: repeating-conic-gradient(#ccc 0% 25%, #fff 0% 50%) 0 0 / 10px 10px;
    }

    /* Firefox — track */
    input[type="range"].range-red::-moz-range-track {
      height: 6px; border-radius: 4px;
      background: linear-gradient(to right, #ffd0d0, #e53e3e);
    }
    input[type="range"].range-green::-moz-range-track {
      height: 6px; border-radius: 4px;
      background: linear-gradient(to right, #d0f5d0, #1a9e4e);
    }
    input[type="range"].range-blue::-moz-range-track {
      height: 6px; border-radius: 4px;
      background: linear-gradient(to right, #d0d8ff, #3b5bdb);
    }
    input[type="range"].range-alpha::-moz-range-track {
      height: 6px; border-radius: 4px;
      background: repeating-conic-gradient(#ccc 0% 25%, #fff 0% 50%) 0 0 / 10px 10px;
    }

    /* Thumb — WebKit */
    input[type="range"].range-red::-webkit-slider-thumb,
    input[type="range"].range-green::-webkit-slider-thumb,
    input[type="range"].range-blue::-webkit-slider-thumb,
    input[type="range"].range-alpha::-webkit-slider-thumb {
      -webkit-appearance: none;
      width: 18px; height: 18px;
      border-radius: 50%;
      background: #fff;
      border: 2px solid #aaa;
      box-shadow: 0 1px 4px rgba(0,0,0,0.2);
      margin-top: -6px;
      cursor: pointer;
      transition: border-color 0.15s, box-shadow 0.15s;
    }
    input[type="range"].range-red::-webkit-slider-thumb   { border-color: #e53e3e; }
    input[type="range"].range-green::-webkit-slider-thumb { border-color: #1a9e4e; }
    input[type="range"].range-blue::-webkit-slider-thumb  { border-color: #3b5bdb; }
    input[type="range"].range-alpha::-webkit-slider-thumb { border-color: #888; }

    input[type="range"].range-red:hover::-webkit-slider-thumb   { box-shadow: 0 0 0 4px rgba(229,62,62,0.2); }
    input[type="range"].range-green:hover::-webkit-slider-thumb { box-shadow: 0 0 0 4px rgba(26,158,78,0.2); }
    input[type="range"].range-blue:hover::-webkit-slider-thumb  { box-shadow: 0 0 0 4px rgba(59,91,219,0.2); }
    input[type="range"].range-alpha:hover::-webkit-slider-thumb { box-shadow: 0 0 0 4px rgba(100,100,100,0.2); }

    /* Thumb — Firefox */
    input[type="range"].range-red::-moz-range-thumb,
    input[type="range"].range-green::-moz-range-thumb,
    input[type="range"].range-blue::-moz-range-thumb,
    input[type="range"].range-alpha::-moz-range-thumb {
      width: 18px; height: 18px;
      border-radius: 50%;
      background: #fff;
      border: 2px solid #aaa;
      box-shadow: 0 1px 4px rgba(0,0,0,0.2);
      cursor: pointer;
    }
    input[type="range"].range-red::-moz-range-thumb   { border-color: #e53e3e; }
    input[type="range"].range-green::-moz-range-thumb { border-color: #1a9e4e; }
    input[type="range"].range-blue::-moz-range-thumb  { border-color: #3b5bdb; }
    input[type="range"].range-alpha::-moz-range-thumb { border-color: #888; }

    /* Number inputs – hide spinners */
    .channel-num {
      width: 68px;
      font-family: 'JetBrains Mono', monospace;
      font-size: 0.84rem;
      text-align: center;
      -moz-appearance: textfield;
    }
    .channel-num::-webkit-inner-spin-button,
    .channel-num::-webkit-outer-spin-button { -webkit-appearance: none; }

    /* Output readonly fields */
    .output-value {
      font-family: 'JetBrains Mono', monospace;
      font-size: 0.86rem;
      background: #fafbff !important;
      border-color: var(--border-color) !important;
      color: #2d2d3a !important;
    }

    /* Colour dot in input-group */
    .color-dot {
      width: 20px; height: 20px;
      border-radius: 50%;
      border: 2px solid rgba(0,0,0,0.09);
      flex-shrink: 0;
      display: inline-block;
      transition: background 0.1s;
    }

    /* HSL stat boxes */
    .hsl-stat {
      background: var(--brand-light);
      border: 1px solid #d0d0f5;
      border-radius: 12px;
      padding: 18px 10px;
      text-align: center;
    }
    .hsl-stat .hsl-num {
      font-family: 'Syne', sans-serif;
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--brand-dark);
      line-height: 1;
    }
    .hsl-stat .hsl-label {
      font-size: 0.68rem;
      text-transform: uppercase;
      letter-spacing: 0.14em;
      color: var(--brand);
      margin-top: 6px;
    }

    /* Shake on invalid paste */
    @keyframes shake {
      0%,100%{ transform:translateX(0); }
      20%{ transform:translateX(-8px); }
      60%{ transform:translateX(8px); }
      80%{ transform:translateX(-4px); }
    }
    .input-shake { animation: shake 0.4s ease; }

    /* Accordion */
    .accordion-button:not(.collapsed) {
      background-color: var(--brand-light);
      color: var(--brand-dark);
      box-shadow: none;
    }
    .accordion-button:focus { box-shadow: none; }
    .accordion-button { font-family: 'Syne', sans-serif; font-weight: 700; font-size: 0.94rem; }

    /* Live badge pulse */
    .badge-live { animation: blink 2s infinite; }
    @keyframes blink { 0%,100%{opacity:1;} 50%{opacity:0.4;} }

    /* How-it-works icon circles */
    .step-icon {
      width: 52px; height: 52px;
      border-radius: 50%;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }

    /* Footer */
    footer.site-footer {
      background: #1e1e2e;
      color: rgba(255,255,255,0.6);
      font-size: 0.78rem;
    }
    footer.site-footer a { color: rgba(255,255,255,0.75); text-decoration: none; }
    footer.site-footer a:hover { color: #fff; }