/* FieldLog Register: paper surfaces, ruled sections, Bitter headings. */
html[data-skin="register"] {
    color-scheme: light;
    --font-family-display: 'Bitter', Georgia, serif;
    --color-primary: #526b59;
    --color-primary-dark: #3f5848;
    --color-primary-accent: #3f5848;
    --color-primary-on: #faf8f3;
    --color-accent-dark: #0e3a5d;
    --bg-primary: #faf8f3;
    --bg-secondary: #f3f0e7;
    --bg-tertiary: #eae6d9;
    --surface-raised: #fffdf8;
    --text-primary: #232b23;
    --text-secondary: #4d574c;
    --text-muted: #5e6f56;
    --border-color: #d9d3c2;
    --border-color-light: #e7e2d3;
    --border-color-strong: #b9b29c;
    --radius-sm: .25rem;
    --radius-md: .375rem;
    --radius-lg: .5rem;
    --radius-xl: .75rem;
    --shadow-sm: none;
    --shadow-md: none;
}
html[data-skin="register"][data-theme="dark"] {
    color-scheme: dark;
    --color-primary-accent: #a9c0ae;
    --bg-primary: #10151c;
    --bg-secondary: #161d26;
    --bg-tertiary: #1d2631;
    --surface-raised: #1a222c;
    --text-primary: #e9e6da;
    --text-secondary: #b7bcae;
    --text-muted: #8b9184;
    --border-color: #29323f;
    --border-color-light: #202834;
    --border-color-strong: #485465;
    --on-tint-brand: #a9c0ae;
    --on-tint-accent: #83b8d8;
}
html { scrollbar-color: var(--border-color-strong) var(--bg-primary); }
::selection { background: var(--color-primary); color: var(--color-primary-on); }
a { color: var(--color-primary-accent); text-underline-offset: .2em; }
a:focus-visible, summary:focus-visible { outline: 2px solid var(--color-primary-accent); outline-offset: 4px; }
.app-header { backdrop-filter: none; }
.header-container, .container, .footer-content { max-width: 1120px; }
.brand { font-family: var(--font-family-display); }
.theme-toggle { min-width: 44px; min-height: 44px; justify-content: center; }
.page-header { display: flex; align-items: center; justify-content: space-between; gap: var(--space-8); margin-bottom: var(--space-8); }
.page-heading { max-width: 70ch; }
.page-title { font-family: var(--font-family-display); font-size: clamp(2.25rem, 5vw, 3rem); line-height: 1.1; letter-spacing: -.015em; }
.page-subtitle { margin-bottom: 0; margin-top: var(--space-3); line-height: 1.6; max-width: 60ch; }
.tabs { gap: 0; border-top: 1px solid var(--border-color); }
.tab-btn { min-height: 44px; }
.tab-btn.active { background: var(--bg-secondary); }
.card { border: 0; border-top: 1px solid var(--border-color); border-radius: 0; padding: var(--space-6) 0; margin-bottom: var(--space-4); box-shadow: none; }
.card:hover { box-shadow: none; }
.card h2, .card h3, .modal__title { font-family: var(--font-family-display); letter-spacing: -.01em; }
.card h2 { font-size: var(--font-size-2xl); }
.card h3 { font-size: var(--font-size-lg); margin-bottom: var(--space-3); }
.setup-prompt { display: flex; flex-direction: row; align-items: center; justify-content: space-between; gap: var(--space-6); text-align: left; }
.setup-prompt__text { max-width: 68ch; margin-bottom: 0; }
.setup-prompt .btn { flex-shrink: 0; }
.mode-description-panel { border-radius: 0; padding: var(--space-4); }
.form-control { background: var(--surface-raised); border-color: var(--border-color-strong); caret-color: var(--color-primary-accent); }
.form-control::placeholder { color: var(--text-muted); opacity: 1; }
.form-control:focus { box-shadow: none; outline: 2px solid var(--color-primary-accent); outline-offset: 2px; }
input[type="number"], .unit, .stat-value, .level-value, .threshold-value, .matching-table td:nth-child(2), .matching-table td:nth-child(3) { font-family: var(--font-family-mono); font-variant-numeric: tabular-nums; }
.btn { min-height: 44px; text-decoration: none; }
.btn-primary:hover:not(:disabled), .btn-success:hover:not(:disabled), .btn-danger:hover:not(:disabled) { transform: none; box-shadow: none; }
.stats-grid { gap: 0; border-block: 1px solid var(--border-color); }
.stat-card { border: 0; border-right: 1px solid var(--border-color); border-radius: 0; background: transparent; box-shadow: none; }
.stat-card:last-child { border-right: 0; }
.mic-list, .pair-card, .results-box, .db-mic-panel { border-radius: var(--radius-sm); }
.mic-item { border-left-width: 1px; }
.pair-card { box-shadow: none; }
.pair-card:hover { transform: none; box-shadow: none; }
.tab-content.active, .mode-desc.active { animation: none; }
#tab-about .card { max-width: 78ch; }
#tab-about p { margin-bottom: var(--space-4); line-height: 1.7; }
#tab-about h3 { margin-top: var(--space-8); }
.technical-details summary { cursor: pointer; padding-block: var(--space-3); font-weight: 600; }
.technical-details p { margin-top: var(--space-3); }
.threshold-input-group { flex-wrap: wrap; min-width: 0; }
.threshold-hint { white-space: normal; }
.advanced-toggle-btn { text-transform: none; letter-spacing: normal; }
.piston-level-btn__unit { text-transform: none; }
.app-footer { background: var(--bg-secondary); }
.footer-content { margin-inline: auto; }
@media (max-width: 768px) {
    .page-header { align-items: flex-start; flex-direction: column; gap: var(--space-4); }
    .setup-prompt { align-items: flex-start; flex-direction: column; gap: var(--space-4); }
    .setup-prompt .btn { width: 100%; }
    .tabs > .tab-btn { flex: 1 0 auto; padding-inline: var(--space-3); }
    .card { padding-block: var(--space-5); }
    .stats-grid { grid-template-columns: 1fr; }
    .stat-card { border-right: 0; border-bottom: 1px solid var(--border-color); }
    .stat-card:last-child { border-bottom: 0; }
}


/* Shared FieldLog footer badges. */
.footer-content { display: flex; align-items: center; justify-content: center; flex-wrap: wrap; gap: 1.25rem; padding-inline: 1rem; }
.footer-brand { font-family: var(--font-family-display); font-weight: 600; text-decoration: none; }
.footer-social { display: flex; align-items: center; gap: .35rem; }
.footer-social a { width: 38px; height: 38px; display: grid; place-items: center; border: 1px solid var(--border-color); border-radius: 50%; color: var(--text-secondary); text-decoration: none; }
.footer-social a:hover, .footer-social a:focus-visible { background: var(--surface-raised); border-color: var(--color-primary-accent); color: var(--color-primary-accent); }
.footer-meta { margin-top: 0; }
@media (max-width: 640px) {
    .footer-social { order: 3; width: 100%; justify-content: center; }
    .footer-social a { width: 44px; height: 44px; }
    .footer-meta { order: 4; width: 100%; text-align: center; }
}