/* ─────────────────────────────────────────────────
   Signal — High-contrast industrial, bold red-blue
   ───────────────────────────────────────────────── */

:root[data-ui-theme="signal"] {
    --bg: #eeebe4;
    --bg-accent: rgba(196, 48, 36, 0.05);
    --text: #121212;
    --sidebar-bg: #e6e2da;
    --sidebar-strong: #f6f3ec;
    --border: rgba(18, 18, 18, 0.1);
    --panel-border: rgba(18, 18, 18, 0.84);
    --panel-bg: #f0ece4;
    --panel-elevated: #f9f6f0;
    --editor-surface: #fbf9f4;
    --muted: #5a544c;
    --input-border: rgba(18, 18, 18, 0.24);
    --button-bg: #121212;
    --button-text: #f9f6f0;
    --link-text: #121212;
    --active-bg: #c43024;
    --active-text: #ffffff;
    --placeholder: #928b82;
    --modal-bg: #f9f6f0;
    --modal-muted: #5a544c;
    --backdrop: rgba(18, 18, 18, 0.44);
    --shadow-soft: 0 16px 40px rgba(18, 18, 18, 0.08), 0 2px 6px rgba(18, 18, 18, 0.04);
    --shadow-panel: 0 4px 14px rgba(18, 18, 18, 0.05);
    --focus-ring: 0 0 0 3px rgba(196, 48, 36, 0.18);
    --accent-red: #c43024;
    --accent-blue: #1c4f96;
    --accent-yellow: #cc9a22;
    --font-ui: "Inter Tight", "Helvetica Neue", Arial, sans-serif;
    --font-display: "Inter Tight", "Helvetica Neue", Arial, sans-serif;
    --font-body: "Space Grotesk", "Helvetica Neue", Arial, sans-serif;
    --font-mono: "JetBrains Mono", "SFMono-Regular", Consolas, monospace;
    --ui-letter-spacing: -0.01em;
    --radius-panel: 16px;
    --radius-card: 12px;
    --radius-input: 10px;
    --radius-note: 12px;
    --radius-button: 10px;
    --radius-icon: 10px;
    --radius-editor: 18px 18px 6px 18px;
    --radius-status: 14px 14px 0 0;
    --label-letter-spacing: 0.16em;
    --label-transform: uppercase;
    --button-letter-spacing: 0.12em;
    --button-transform: uppercase;
    --button-weight: 800;
    --title-letter-spacing: -0.04em;
    --title-transform: uppercase;
    --title-max-width: none;
    --display-letter-spacing: -0.05em;
    --display-transform: uppercase;
    --display-max-width: 10ch;
    --editor-font-size: 1rem;
    --editor-line-height: 1.76;
}

:root[data-ui-theme="signal"] body {
    background:
        linear-gradient(90deg, rgba(18, 18, 18, 0.03) 1px, transparent 1px),
        var(--bg);
    background-size: 48px 48px, auto;
}

:root[data-ui-theme="signal"] .sidebar {
    box-shadow: inset -1px 0 0 rgba(255, 255, 255, 0.3);
}

:root[data-ui-theme="signal"] .title-row h1 {
    font-size: 2.2rem;
    font-weight: 800;
}

:root[data-ui-theme="signal"] .icon-button {
    background: rgba(18, 18, 18, 0.04);
    border-width: 1.5px;
}

:root[data-ui-theme="signal"] .sidebar-count {
    background: var(--accent-red);
    border-radius: 8px;
}

:root[data-ui-theme="signal"] #notes li {
    border-color: rgba(18, 18, 18, 0.09);
}

:root[data-ui-theme="signal"] #notes li:hover {
    border-color: rgba(18, 18, 18, 0.2);
}

:root[data-ui-theme="signal"] #notes li.active {
    background: var(--accent-red);
    box-shadow: 6px 6px 0 rgba(28, 79, 150, 0.2);
}

:root[data-ui-theme="signal"] .welcome-badge {
    background: rgba(196, 48, 36, 0.1);
    border-color: rgba(196, 48, 36, 0.22);
}

:root[data-ui-theme="signal"] .welcome-hero {
    border-color: var(--panel-border);
}

:root[data-ui-theme="signal"] .editor-body {
    box-shadow: var(--shadow-soft);
}

:root[data-ui-theme="signal"] .modal-card {
    box-shadow: 0 12px 40px rgba(18, 18, 18, 0.14);
}