:root {
    --bg: #060a0e;
    --surface: #0f1520;
    --surface2: #162030;
    --surface3: #1e2d40;
    --border: #253545;
    --border2: #2e4258;
    --accent: #00d4ff;
    --accent2: #00ff9d;
    --accent3: #ff6b35;
    --accent4: #c87bff;
    --text: #f0f8ff;
    --text2: #b0cfe8;
    --text3: #7a9dba;
    --mono: 'Space Mono', monospace;
    --sans: 'Syne', sans-serif;
    --glow: 0 0 20px rgba(0,212,255,0.15);
    --glow2: 0 0 30px rgba(0,255,157,0.1);
  }

  * { margin: 0; padding: 0; box-sizing: border-box; }

  body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--sans);
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
  }

  body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
      linear-gradient(rgba(0,212,255,0.03) 1px, transparent 1px),
      linear-gradient(90deg, rgba(0,212,255,0.03) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    z-index: 0;
  }

  body::after {
    content: '';
    position: fixed;
    top: -50%; left: -50%;
    width: 200%; height: 200%;
    background:
      radial-gradient(ellipse at 25% 25%, rgba(0,212,255,0.04) 0%, transparent 50%),
      radial-gradient(ellipse at 75% 75%, rgba(200,123,255,0.03) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
    animation: drift 20s ease-in-out infinite alternate;
  }

  @keyframes drift {
    from { transform: translate(0,0) rotate(0deg); }
    to   { transform: translate(20px,10px) rotate(1deg); }
  }

  .container {
    position: relative;
    z-index: 1;
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px 60px;
  }

  /* ── Header ── */
  header {
    padding: 40px 0 48px;
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
    margin-bottom: 40px;
  }

  .logo-group { display: flex; flex-direction: column; gap: 6px; }

  .logo-tag {
    font-family: var(--mono);
    font-size: 11px;
    color: var(--accent);
    letter-spacing: 3px;
    text-transform: uppercase;
  }

  .logo-title {
    font-size: 38px;
    font-weight: 800;
    letter-spacing: -1px;
    color: var(--text);
    line-height: 1;
  }

  .logo-title span { color: var(--accent); }

  .header-badge {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 4px;
  }

  .badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 5px 12px;
    border: 1px solid var(--border2);
    border-radius: 2px;
    font-family: var(--mono);
    font-size: 10px;
    color: var(--accent2);
    letter-spacing: 1px;
    background: rgba(0,255,157,0.04);
  }

  .badge::before {
    content: '';
    width: 6px; height: 6px;
    border-radius: 50%;
    background: var(--accent2);
    box-shadow: 0 0 8px var(--accent2);
    animation: pulse 2s ease-in-out infinite;
  }

  @keyframes pulse {
    0%,100% { opacity: 1; }
    50%      { opacity: 0.3; }
  }

  /* ── Info banner ── */
  .info-banner {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 18px;
    margin-bottom: 24px;
    background: rgba(0,212,255,0.03);
    border: 1px solid rgba(0,212,255,0.12);
    border-radius: 3px;
    font-family: var(--mono);
    font-size: 11px;
    color: #5a8fa8;
    letter-spacing: 0.3px;
  }

  .info-banner strong { color: var(--accent); }

  /* ── Panel shell ── */
  .panel {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 28px;
    margin-bottom: 24px;
    position: relative;
    overflow: hidden;
  }

  .panel::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent), transparent);
    opacity: 0.35;
  }

  .panel.green-line::before {
    background: linear-gradient(90deg, transparent, var(--accent2), transparent);
  }

  .panel.purple-line::before {
    background: linear-gradient(90deg, transparent, var(--accent4), transparent);
  }

  .panel.orange-line::before {
    background: linear-gradient(90deg, transparent, var(--accent3), transparent);
  }

  .panel-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 22px;
  }

  .panel-icon {
    width: 28px; height: 28px;
    background: var(--surface3);
    border: 1px solid var(--border2);
    border-radius: 3px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent);
    font-size: 14px;
    flex-shrink: 0;
  }

  .panel-title {
    font-size: 13px;
    font-weight: 600;
    color: #c0ddf0;
    letter-spacing: 2px;
    text-transform: uppercase;
  }

  /* ── Config grid ── */
  .config-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
  }

  .field-group { display: flex; flex-direction: column; gap: 8px; }

  .field-label {
    font-family: var(--mono);
    font-size: 10px;
    color: #8bbcd8;
    letter-spacing: 2px;
    text-transform: uppercase;
  }

  .field-label-link {
    text-decoration: none;
    cursor: pointer;
    display: inline-block;
    border-bottom: 1px dashed #2e4258;
    transition: color 0.15s, border-color 0.15s;
  }

  .field-label-link:hover {
    color: var(--accent);
    border-color: var(--accent);
  }

  .select-wrapper { position: relative; }

  .select-wrapper::after {
    content: '▾';
    position: absolute;
    right: 12px; top: 50%;
    transform: translateY(-50%);
    color: var(--accent);
    font-size: 11px;
    pointer-events: none;
  }

  .field-select, .field-input {
    background: var(--surface2);
    border: 1px solid var(--border);
    color: #dff0ff;
    font-family: var(--mono);
    font-size: 13px;
    padding: 10px 14px;
    border-radius: 3px;
    outline: none;
    transition: all 0.2s;
    width: 100%;
    appearance: none;
    -webkit-appearance: none;
    cursor: pointer;
  }

  .field-select:focus, .field-input:focus {
    border-color: var(--accent);
    background: var(--surface3);
    box-shadow: var(--glow);
  }

  /* ── Input section ── */
  .input-area {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 4px;
    margin-bottom: 24px;
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
  }

  .input-area::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255,107,53,0.5), transparent);
  }

  .io-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 18px;
    border-bottom: 1px solid var(--border);
    background: var(--surface2);
  }

  .io-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: #c8e0f0;
  }

  .io-dot {
    width: 8px; height: 8px;
    border-radius: 50%;
    background: var(--accent3);
    box-shadow: 0 0 8px var(--accent3);
  }

  .io-actions { display: flex; gap: 6px; align-items: center; }

  .icon-btn {
    background: transparent;
    border: 1px solid var(--border2);
    color: #7aaccb;
    width: 28px; height: 28px;
    border-radius: 3px;
    cursor: pointer;
    font-size: 12px;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .icon-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(0,212,255,0.05);
  }

  .upload-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 0 12px;
    height: 28px;
    background: rgba(255,107,53,0.1);
    border: 1px solid var(--accent3);
    border-radius: 3px;
    color: var(--accent3);
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 1px;
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
  }

  .upload-btn:hover {
    background: rgba(255,107,53,0.2);
    box-shadow: 0 0 14px rgba(255,107,53,0.25);
  }

  .io-textarea {
    flex: 1;
    background: transparent;
    border: none;
    color: #e8f4ff;
    font-family: var(--mono);
    font-size: 13px;
    line-height: 1.7;
    padding: 18px;
    resize: none;
    outline: none;
    min-height: 160px;
  }

  .io-textarea::placeholder { color: #4a6e8a; }

  .io-footer {
    padding: 8px 18px;
    border-top: 1px solid var(--border);
    background: var(--surface2);
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  .io-stat {
    font-family: var(--mono);
    font-size: 10px;
    color: #7aafc8;
  }

  .format-tabs { display: flex; gap: 4px; }

  .format-tab {
    background: transparent;
    border: 1px solid transparent;
    color: #7aafc8;
    font-family: var(--mono);
    font-size: 10px;
    padding: 3px 8px;
    border-radius: 2px;
    cursor: pointer;
    letter-spacing: 1px;
    transition: all 0.15s;
  }

  .format-tab.active {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(0,212,255,0.08);
  }

  .format-tab:hover:not(.active) {
    border-color: var(--border2);
    color: var(--text2);
  }

  /* file preview mode */
  .io-textarea.preview-mode {
    color: #7aafc8;
    cursor: default;
    user-select: text;
  }

  .preview-type-badge {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 2px 8px;
    font-family: var(--mono);
    font-size: 9px;
    letter-spacing: 1px;
    border-radius: 2px;
    border: 1px solid var(--border2);
    color: var(--text3);
    background: var(--surface3);
  }

  .preview-type-badge.text { color: var(--accent2); border-color: rgba(0,255,157,0.25); }
  .preview-type-badge.binary { color: var(--accent); border-color: rgba(0,212,255,0.25); }

  /* file badge */
  .file-badge {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 4px 10px;
    background: rgba(0,212,255,0.08);
    border: 1px solid rgba(0,212,255,0.25);
    border-radius: 2px;
    font-family: var(--mono);
    font-size: 10px;
    color: var(--accent);
    max-width: 200px;
  }

  .file-badge-name {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .file-badge-clear {
    cursor: pointer;
    color: var(--text3);
    flex-shrink: 0;
    background: none;
    border: none;
    font-size: 11px;
    padding: 0;
    line-height: 1;
    transition: color 0.15s;
  }

  .file-badge-clear:hover { color: var(--accent3); }

  /* ── Action row ── */
  .action-row {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
    align-items: stretch;
  }

  .primary-btn {
    flex: 1;
    padding: 16px 28px;
    border: 1px solid;
    border-radius: 3px;
    font-family: var(--mono);
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 2px;
    text-transform: uppercase;
    cursor: pointer;
    transition: all 0.25s;
    position: relative;
    overflow: hidden;
    background: rgba(0,212,255,0.08);
    border-color: var(--accent);
    color: var(--accent);
  }

  .primary-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(0,212,255,0.1), transparent);
    opacity: 0;
    transition: opacity 0.25s;
  }

  .primary-btn:hover::before { opacity: 1; }
  .primary-btn:hover {
    box-shadow: 0 0 30px rgba(0,212,255,0.2), inset 0 0 30px rgba(0,212,255,0.05);
    transform: translateY(-1px);
  }

  .primary-btn:active { transform: translateY(0); }

  .clear-btn {
    padding: 16px 22px;
    border: 1px dashed var(--border2);
    border-radius: 3px;
    background: transparent;
    color: var(--text3);
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 1px;
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
  }

  .clear-btn:hover {
    border-color: var(--accent3);
    color: var(--accent3);
    background: rgba(255,107,53,0.05);
  }

  /* ── Status bar ── */
  .status-bar {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 3px;
    padding: 12px 18px;
    display: flex;
    align-items: center;
    gap: 12px;
    min-height: 46px;
    font-family: var(--mono);
    font-size: 12px;
    margin-bottom: 24px;
    transition: all 0.3s;
  }

  .status-bar.success {
    border-color: rgba(0,255,157,0.3);
    background: rgba(0,255,157,0.04);
  }

  .status-bar.error {
    border-color: rgba(255,100,100,0.3);
    background: rgba(255,100,100,0.04);
  }

  .status-indicator {
    width: 8px; height: 8px;
    border-radius: 50%;
    background: var(--text3);
    flex-shrink: 0;
    transition: all 0.3s;
  }

  .status-bar.success .status-indicator {
    background: var(--accent2);
    box-shadow: 0 0 10px var(--accent2);
  }

  .status-bar.error .status-indicator {
    background: #ff6464;
    box-shadow: 0 0 10px #ff6464;
  }

  .status-text { color: #a0c8e0; flex: 1; }
  .status-bar.success .status-text { color: var(--accent2); }
  .status-bar.error   .status-text { color: #ff6464; }

  .status-time { color: #6a9ab8; font-size: 10px; }

  @keyframes statusShake {
    0%,100% { transform: translateX(0); }
    15%     { transform: translateX(-6px); }
    30%     { transform: translateX(6px); }
    45%     { transform: translateX(-4px); }
    60%     { transform: translateX(4px); }
    75%     { transform: translateX(-2px); }
    90%     { transform: translateX(2px); }
  }

  .status-bar.shake { animation: statusShake 0.45s ease; }

  /* error message link inside status bar */
  .status-link {
    color: inherit;
    text-decoration: none;
    border-bottom: 1px dashed rgba(255,100,100,0.5);
    transition: border-color 0.15s, opacity 0.15s;
  }
  .status-link:hover { opacity: 0.75; border-color: #ff6464; }

  /* disabled encoding tabs when file is loaded */
  .format-tab:disabled,
  .format-tab.tab-disabled {
    opacity: 0.28;
    cursor: not-allowed;
    pointer-events: none;
  }

  /* ── Results layout ── */
  .result-primary {
    background: var(--surface3);
    border: 1px solid var(--accent);
    border-radius: 4px;
    padding: 22px 24px 16px;
    margin-bottom: 12px;
    position: relative;
    box-shadow: 0 0 24px rgba(0,212,255,0.08);
  }

  .result-primary::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent), transparent);
    border-radius: 4px 4px 0 0;
  }

  .result-primary-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: 14px;
  }

  .result-primary-meta {
    display: flex;
    flex-direction: column;
    gap: 4px;
  }

  .result-primary-name {
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--accent);
  }

  .result-primary-desc {
    font-family: var(--mono);
    font-size: 10px;
    color: #4a6e8a;
    letter-spacing: 0.3px;
  }

  .result-copy-primary {
    background: rgba(0,212,255,0.08) !important;
    border-color: var(--accent) !important;
    color: var(--accent) !important;
    padding: 4px 14px !important;
    font-size: 10px !important;
  }

  .result-copy-primary:hover {
    background: rgba(0,212,255,0.18) !important;
    box-shadow: 0 0 12px rgba(0,212,255,0.2);
  }

  .result-primary-value {
    font-family: var(--mono);
    font-size: 28px;
    font-weight: 700;
    color: var(--accent);
    letter-spacing: 1px;
    margin-bottom: 14px;
    min-height: 38px;
    word-break: break-all;
    text-shadow: 0 0 20px rgba(0,212,255,0.3);
  }

  .result-primary-value.empty {
    color: #3a5a72;
    font-size: 22px;
    font-weight: 400;
    text-shadow: none;
  }

  .result-primary-fmts {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    padding-top: 12px;
    border-top: 1px solid var(--border);
  }

  /* secondary row */
  .result-secondary-row {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
  }

  .result-secondary {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 3px;
    padding: 10px 12px;
    opacity: 0.55;
    transition: opacity 0.2s, border-color 0.2s;
    cursor: pointer;
  }

  .result-secondary:hover { opacity: 0.8; }

  .result-secondary.is-active {
    opacity: 1;
    border-color: var(--accent);
    box-shadow: 0 0 10px rgba(0,212,255,0.08);
  }

  .result-secondary-label {
    font-family: var(--mono);
    font-size: 9px;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: #4a6e8a;
    margin-bottom: 5px;
  }

  .result-secondary-val {
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 700;
    color: var(--text2);
    word-break: break-all;
  }

  .result-secondary-val.empty { color: #2e4258; }

  .result-copy-btn {
    background: transparent;
    border: 1px solid var(--border2);
    color: #7aaccb;
    padding: 3px 10px;
    border-radius: 2px;
    cursor: pointer;
    font-family: var(--mono);
    font-size: 9px;
    letter-spacing: 1px;
    transition: all 0.2s;
    white-space: nowrap;
  }

  .result-copy-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(0,212,255,0.05);
  }

  .result-copy-btn.copied {
    border-color: var(--accent2);
    color: var(--accent2);
    background: rgba(0,255,157,0.06);
  }

  .result-value {
    padding: 14px 14px;
    font-family: var(--mono);
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 0.5px;
    color: var(--accent);
    min-height: 50px;
    display: flex;
    align-items: center;
    word-break: break-all;
    line-height: 1.5;
  }

  .result-value.empty {
    color: #3a5a72;
    font-weight: 400;
    font-size: 12px;
  }

  .result-formats {
    padding: 0 14px 12px;
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
  }

  .fmt-pill {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 3px 8px;
    border-radius: 2px;
    font-family: var(--mono);
    font-size: 10px;
    background: var(--surface3);
    border: 1px solid var(--border);
    color: var(--text3);
    cursor: pointer;
    transition: all 0.15s;
    white-space: nowrap;
  }

  .fmt-pill:hover {
    border-color: var(--accent);
    color: var(--accent);
  }

  .fmt-pill .fmt-label { color: #4a6e8a; }

  /* ── Verify section ── */
  .verify-row {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 12px;
    align-items: flex-end;
  }

  .verify-result {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 18px;
    border-radius: 3px;
    font-family: var(--mono);
    font-size: 12px;
    margin-top: 12px;
    border: 1px solid var(--border);
    background: var(--surface2);
    transition: all 0.3s;
    min-height: 42px;
  }

  .verify-result.match {
    border-color: rgba(0,255,157,0.35);
    background: rgba(0,255,157,0.05);
    color: var(--accent2);
  }

  .verify-result.mismatch {
    border-color: rgba(255,100,100,0.35);
    background: rgba(255,100,100,0.05);
    color: #ff6464;
  }

  .verify-btn {
    padding: 10px 20px;
    background: rgba(200,123,255,0.08);
    border: 1px solid var(--accent4);
    border-radius: 3px;
    color: var(--accent4);
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 1.5px;
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
    text-transform: uppercase;
    height: 42px;
  }

  .verify-btn:hover {
    background: rgba(200,123,255,0.15);
    box-shadow: 0 0 20px rgba(200,123,255,0.15);
  }

  /* ── Info strip ── */
  .info-strip {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-top: 24px;
  }

  .info-cell {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 3px;
    padding: 14px 16px;
    display: flex;
    flex-direction: column;
    gap: 6px;
  }

  .info-cell-label {
    font-family: var(--mono);
    font-size: 9px;
    color: var(--text3);
    letter-spacing: 1.5px;
    text-transform: uppercase;
  }

  .info-cell-value {
    font-family: var(--mono);
    font-size: 16px;
    font-weight: 700;
    color: var(--accent);
  }

  /* ── Explain section ── */
  .explain-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
    margin-top: 0;
  }

  .explain-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 20px 22px;
    position: relative;
    overflow: hidden;
  }

  .explain-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 1px;
    background: linear-gradient(90deg, transparent, rgba(0,212,255,0.2), transparent);
    transition: background 0.3s;
  }

  .explain-card--lit {
    border-color: var(--accent) !important;
    box-shadow: 0 0 0 1px var(--accent), 0 0 28px rgba(0,212,255,0.14);
    transition: border-color 0.2s, box-shadow 0.2s;
  }

  .explain-card--lit::before {
    background: linear-gradient(90deg, transparent, var(--accent), transparent) !important;
    opacity: 0.7;
  }

  @keyframes cardLitFade {
    0%   { box-shadow: 0 0 0 1px var(--accent), 0 0 36px rgba(0,212,255,0.22); }
    100% { box-shadow: none; border-color: var(--border); }
  }

  .explain-card-title {
    font-size: 12px;
    font-weight: 700;
    color: #c8e0f0;
    letter-spacing: 0.3px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .explain-card-title .etag {
    font-family: var(--mono);
    font-size: 9px;
    padding: 2px 7px;
    border: 1px solid var(--border2);
    border-radius: 2px;
    color: var(--accent);
    letter-spacing: 1px;
  }

  .explain-card-text {
    font-family: var(--mono);
    font-size: 11px;
    line-height: 1.9;
    color: #8ab5d0;
  }

  /* ── Toast ── */
  .toast {
    position: fixed;
    bottom: 32px;
    right: 32px;
    z-index: 999;
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 11px 20px;
    background: var(--surface3);
    border: 1px solid var(--border2);
    border-radius: 4px;
    font-family: var(--mono);
    font-size: 12px;
    color: var(--text2);
    box-shadow: 0 8px 32px rgba(0,0,0,0.5);
    opacity: 0;
    transform: translateY(12px);
    transition: all 0.25s ease;
    pointer-events: none;
  }

  .toast.show {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
  }

  .toast.success { border-color: rgba(0,255,157,0.3); color: var(--accent2); }
  .toast.error   { border-color: rgba(255,100,100,0.3); color: #ff8080; }

  /* ── Drop zone ── */
  .drop-zone {
    position: absolute;
    inset: 0;
    border: 2px dashed var(--accent);
    border-radius: 4px;
    background: rgba(0,212,255,0.06);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    z-index: 10;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s;
  }

  .drop-zone.active { opacity: 1; pointer-events: all; }

  .drop-zone-text {
    font-family: var(--mono);
    font-size: 12px;
    color: var(--accent);
    letter-spacing: 1px;
  }

  /* ── Flash animations ── */
  @keyframes flashRed {
    0%   { box-shadow: none; border-color: var(--border); }
    20%  { box-shadow: 0 0 0 3px rgba(255,80,80,0.5); border-color: #ff5050; }
    100% { box-shadow: none; border-color: var(--border); }
  }

  .field-error { animation: flashRed 0.7s ease forwards; }

  @keyframes resultFlash {
    0%   { background: rgba(0,212,255,0.15); }
    100% { background: transparent; }
  }

  .result-flash { animation: resultFlash 0.5s ease forwards; }

  /* ── Label anchor links ── */
  .field-label-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  .label-link {
    font-family: var(--mono);
    font-size: 9px;
    color: var(--text3);
    text-decoration: none;
    letter-spacing: 1px;
    border-bottom: 1px dashed #2e4258;
    transition: color 0.15s, border-color 0.15s;
    display: inline-flex;
    align-items: center;
    gap: 3px;
  }

  .label-link:hover {
    color: var(--accent);
    border-color: var(--accent);
  }

  /* ── Explain section anchors & highlight ── */
  .explain-section-wrap {
    scroll-margin-top: 24px;
    border-radius: 4px;
    transition: box-shadow 0.4s, border-color 0.4s;
  }

  .explain-section-wrap.highlighted {
    box-shadow: 0 0 0 1px var(--accent), 0 0 28px rgba(0,212,255,0.12);
  }

  .explain-section-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 24px;
    margin-bottom: 8px;
  }

  .explain-section-tag {
    font-family: var(--mono);
    font-size: 11px;
    color: #4a6e8a;
    letter-spacing: 2px;
    text-transform: uppercase;
  }

  .explain-section-badge {
    font-family: var(--mono);
    font-size: 9px;
    padding: 2px 8px;
    border: 1px solid var(--border2);
    border-radius: 2px;
    color: var(--accent);
    background: rgba(0,212,255,0.04);
    letter-spacing: 1px;
  }

  /* Variant param table inside explain card */
  .param-table {
    margin-top: 10px;
    width: 100%;
    border-collapse: collapse;
    font-family: var(--mono);
    font-size: 10px;
  }

  .param-table td {
    padding: 4px 8px;
    border: 1px solid var(--border);
    color: #8ab5d0;
    vertical-align: top;
  }

  .param-table td:first-child {
    color: #4a6e8a;
    white-space: nowrap;
    background: var(--surface3);
    width: 90px;
  }

  .param-table td code {
    color: var(--accent);
    font-family: var(--mono);
  }

  /* ── Responsive ── */
  @media (max-width: 760px) {
    .config-grid { grid-template-columns: 1fr 1fr; }
    .results-grid { grid-template-columns: 1fr; }
    .info-strip { grid-template-columns: repeat(2, 1fr); }
    .explain-grid { grid-template-columns: 1fr; }
    header { flex-direction: column; align-items: flex-start; gap: 16px; }
    .logo-title { font-size: 28px; }
    .action-row { flex-direction: column; }
  }