@font-face {
            font-family: 'JetBrains Mono';
            src: url('fonts/JetBrainsMono-Regular.woff2') format('woff2');
            font-weight: 400;
            font-style: normal;
            font-display: swap;
        }

        :root {
            /* Page background */
            --color-bg:           #0f172a;
            /* Card & surfaces */
            --color-surface:      #1e293b;
            --color-surface-alt:  #111827;
            --color-border:       #334155;
            /* Text */
            --color-text:         #e2e8f0;
            --color-text-heading: #f8fafc;
            --color-text-muted:   #64748b;
            --color-text-subtle:  #94a3b8;
            --color-text-faint:   #475569;
            /* Inputs — separate from page bg so each can be themed independently */
            --color-input-bg:     #0f172a;
            --color-input-text:   #f1f5f9;
            /* Accents */
            --color-accent:       #3b82f6;
            --color-accent-hover: #2563eb;
            --color-accent-light: #38bdf8;
            --color-green:        #4ade80;
            /* Error */
            --color-error-bg:     #450a0a;
            --color-error-border: #7f1d1d;
            --color-error-text:   #fca5a5;
            /* Button text */
            --color-btn-text:     #fff;
        }

        html[data-theme="light"] {
            --color-bg:           #fff;
            --color-surface:      #fff;
            --color-surface-alt:  #f8fafc;
            --color-border:       #cbd5e1;
            --color-text:         #1e293b;
            --color-text-heading: #0f172a;
            --color-text-muted:   #4b5563;
            --color-text-subtle:  #475569;
            --color-text-faint:   #6b7280;
            --color-input-bg:     #fff;
            --color-input-text:   #0f172a;
            --color-accent:       #3b82f6;
            --color-accent-hover: #2563eb;
            --color-accent-light: #1d4ed8;
            --color-green:        #16a34a;
            --color-error-bg:     #fef2f2;
            --color-error-border: #fca5a5;
            --color-error-text:   #dc2626;
            --color-btn-text:     #fff;
        }

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

        body {
            font-family: system-ui, -apple-system, sans-serif;
            background: var(--color-bg);
            color: var(--color-text);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 2rem 1rem;
        }

        .skip-link {
            position: absolute;
            top: -100%;
            left: 1rem;
            padding: 0.5rem 1rem;
            background: var(--color-accent);
            color: var(--color-btn-text);
            border-radius: 0 0 6px 6px;
            font-weight: 600;
            font-size: 0.875rem;
            text-decoration: none;
            z-index: 1000;
            transition: top 0.1s;
        }
        .skip-link:focus { top: 0; }

        .card {
            background: var(--color-surface);
            border: 1px solid var(--color-border);
            border-radius: 12px;
            padding: 2rem;
            width: 100%;
            max-width: 560px;
        }

        .title-row {
            display: flex;
            align-items: center;
            gap: 0.6rem;
            margin-bottom: 1.25rem;
        }

        .logo { width: 48px; height: 48px; flex-shrink: 0; }

        h1 { font-size: 1.5rem; font-weight: 700; color: var(--color-text-heading); }

        .version {
            font-size: 0.7rem;
            font-weight: 600;
            color: var(--color-text-faint);
            background: var(--color-surface);
            border: 1px solid var(--color-border);
            border-radius: 4px;
            padding: 0.15rem 0.4rem;
            letter-spacing: 0.04em;
        }

        /* Tabs */
        .tabs {
            display: flex;
            border-bottom: 1px solid var(--color-border);
            margin-bottom: 1.5rem;
        }

        .tab-btn {
            background: none;
            border: none;
            border-bottom: 2px solid transparent;
            border-radius: 0;
            color: var(--color-text-muted);
            cursor: pointer;
            flex: 0;
            font-size: 0.875rem;
            font-weight: 600;
            margin-bottom: -1px;
            padding: 0.5rem 1.25rem;
            transition: color 0.15s, border-color 0.15s;
            width: auto;
        }

        .tab-btn:hover { background: none; color: var(--color-text); }
        .tab-btn.active { border-bottom-color: var(--color-accent); color: var(--color-accent-light); }

        .panel { display: none; }
        .panel.active { display: block; }

        /* Form */
        .form-row {
            display: flex;
            gap: 0.75rem;
            margin-bottom: 1rem;
        }

        .form-group { display: flex; flex-direction: column; flex: 1; }

        label {
            font-size: 0.75rem;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 0.05em;
            color: var(--color-text-subtle);
            margin-bottom: 0.4rem;
        }

        input[type="text"] {
            background: var(--color-input-bg);
            border: 1px solid var(--color-border);
            border-radius: 6px;
            color: var(--color-input-text);
            font-family: 'JetBrains Mono', 'Courier New', monospace;
            font-size: 1rem;
            padding: 0.55rem 0.75rem;
            transition: border-color 0.15s;
            width: 100%;
        }

        input[type="number"] { font-size: 1rem; }

        input[type="text"]:focus-visible,
        input[type="number"]:focus-visible,
        textarea:focus-visible {
            outline: 2px solid var(--color-accent);
            outline-offset: 1px;
            border-color: var(--color-accent);
        }
        input[type="text"]::placeholder { color: var(--color-text-faint); }

        .btn-row { display: flex; gap: 0.75rem; margin-top: 0.25rem; }

        button[type="submit"] {
            flex: 1;
            background: var(--color-accent);
            border: none;
            border-radius: 6px;
            color: var(--color-btn-text);
            cursor: pointer;
            font-size: 0.95rem;
            font-weight: 600;
            padding: 0.65rem 1rem;
            transition: background 0.15s;
        }

        button[type="submit"]:hover { background: var(--color-accent-hover); }

        a.btn.reset {
            flex: 1;
            background: var(--color-input-bg);
            border: 1px solid var(--color-border);
            border-radius: 6px;
            color: var(--color-text-subtle);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 0.95rem;
            font-weight: 600;
            padding: 0.65rem 1rem;
            text-decoration: none;
            transition: background 0.15s, color 0.15s;
        }

        a.btn.reset:hover { background: var(--color-border); color: var(--color-text); }

        /* Error */
        .error {
            background: var(--color-error-bg);
            border: 1px solid var(--color-error-border);
            border-radius: 6px;
            color: var(--color-error-text);
            font-size: 0.875rem;
            margin-top: 1.25rem;
            padding: 0.65rem 0.85rem;
        }

        /* Results */
        .results {
            margin-top: 1.5rem;
            border: 1px solid var(--color-border);
            border-radius: 8px;
            overflow: hidden;
        }

        .results-header {
            background: var(--color-input-bg);
            color: var(--color-text-muted);
            font-size: 0.7rem;
            font-weight: 700;
            letter-spacing: 0.08em;
            padding: 0.6rem 1rem;
            text-transform: uppercase;
        }

        .result-row {
            align-items: center;
            background: var(--color-input-bg);
            border-top: 1px solid var(--color-surface);
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            padding: 0.65rem 1rem;
            transition: background 0.1s;
        }

        .result-row:nth-child(odd) { background: var(--color-surface-alt); }
        .result-row:hover { background: var(--color-border) !important; }

        .result-label { color: var(--color-text-subtle); font-size: 0.8rem; }

        .result-value {
            color: var(--color-accent-light);
            font-family: 'JetBrains Mono', 'Courier New', monospace;
            font-size: 0.9rem;
            font-weight: 600;
        }

        .result-value::after {
            content: ' \29d8';
            color: transparent;
            font-size: 0.8em;
            transition: color 0.15s;
        }

        .result-row:hover .result-value::after { color: var(--color-text-faint); }

        .hosts-row .result-value { color: var(--color-green); }

        /* Address type badge */
        .badge {
            border-radius: 4px;
            font-size: 0.72rem;
            font-weight: 600;
            padding: 0.15rem 0.45rem;
        }
        .badge-private   { background: rgb(245 158 11 / 15%); color: #f59e0b; }
        .badge-public    { background: rgb(74 222 128 / 15%); color: #4ade80; }
        .badge-loopback  { background: rgb(167 139 250 / 15%); color: #a78bfa; }
        .badge-link-local{ background: rgb(251 191 36 / 15%); color: #fbbf24; }
        .badge-multicast { background: rgb(248 113 113 / 15%); color: #f87171; }
        .badge-doc       { background: rgb(96 165 250 / 15%); color: #60a5fa; }
        .badge-ula       { background: rgb(148 163 184 / 15%); color: var(--color-text-subtle); }
        .badge-other     { background: rgb(148 163 184 / 15%); color: var(--color-text-subtle); }

        html[data-theme="light"] .badge-private   { color: #92400e; }
        html[data-theme="light"] .badge-public    { color: #14532d; }
        html[data-theme="light"] .badge-loopback  { color: #4c1d95; }
        html[data-theme="light"] .badge-link-local{ color: #78350f; }
        html[data-theme="light"] .badge-multicast { color: #991b1b; }
        html[data-theme="light"] .badge-doc       { color: #1e3a5f; }

        /* Theme toggle */
        .theme-toggle {
            background: none;
            border: 1px solid var(--color-border);
            border-radius: 6px;
            color: var(--color-text-subtle);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-left: auto;
            padding: 0.3rem 0.4rem;
            transition: background 0.15s, color 0.15s;
        }
        .theme-toggle:hover { background: var(--color-border); color: var(--color-text); }
        .icon-moon { display: none; }
        html[data-theme="light"] .icon-moon { display: block; }
        html[data-theme="light"] .icon-sun  { display: none; }

        /* Honeypot — always hidden regardless of CSS cascade */
        .sc-honeypot { display: none !important; }

        /* Turnstile container */
        .cf-turnstile { margin-top: 0.75rem; }

        footer {
            margin-top: 1.25rem;
            text-align: center;
        }

        footer a {
            color: var(--color-text-faint);
            font-size: 0.75rem;
            text-decoration: none;
            transition: color 0.15s;
        }

        footer a:hover { color: var(--color-text-subtle); }

        /* Share bar */
        .share-bar {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            margin-top: 0.75rem;
            background: var(--color-surface-alt);
            border: 1px solid var(--color-border);
            border-radius: 6px;
            padding: 0.5rem 0.75rem;
        }

        .share-label {
            color: var(--color-text-faint);
            font-size: 0.7rem;
            font-weight: 600;
            flex-shrink: 0;
            text-transform: uppercase;
            letter-spacing: 0.05em;
        }

        .share-url {
            color: var(--color-text-subtle);
            font-family: 'JetBrains Mono', 'Courier New', monospace;
            font-size: 0.75rem;
            flex: 1;
            word-break: break-all;
            overflow-wrap: anywhere;
            user-select: all;
        }

        .share-copy {
            background: none;
            border: 1px solid var(--color-border);
            border-radius: 4px;
            color: var(--color-text-subtle);
            cursor: pointer;
            font-size: 0.7rem;
            font-weight: 600;
            padding: 0.2rem 0.5rem;
            flex-shrink: 0;
            transition: background 0.15s, color 0.15s;
        }

        .share-copy:hover { background: var(--color-border); color: var(--color-text); }

        /* Toast */
        .toast {
            position: fixed;
            bottom: 1.5rem;
            left: 50%;
            transform: translateX(-50%) translateY(0.5rem);
            background: var(--color-surface);
            border: 1px solid var(--color-border);
            border-radius: 6px;
            color: var(--color-text);
            font-size: 0.8rem;
            font-weight: 600;
            opacity: 0%;
            padding: 0.5rem 1rem;
            pointer-events: none;
            transition: opacity 0.2s, transform 0.2s;
            z-index: 100;
        }

        .toast.show {
            opacity: 100%;
            transform: translateX(-50%) translateY(0);
        }

        /* Binary representation */
        .binary-details {
            margin-top: 0.75rem;
            border: 1px solid var(--color-border);
            border-radius: 6px;
            padding: 0 0.75rem;
        }

        .binary-details summary {
            cursor: pointer;
            font-size: 0.78rem;
            color: var(--color-text-faint);
            padding: 0.45rem 0;
            user-select: none;
        }

        .binary-details summary:hover { color: var(--color-text); }

        .binary-details[open] summary { border-bottom: 1px solid var(--color-border); margin-bottom: 0.5rem; }

        .binary-grid {
            display: grid;
            grid-template-columns: max-content 1fr;
            gap: 0.25rem 0.75rem;
            align-items: center;
            margin-bottom: 0.4rem;
        }

        .bin-label {
            font-size: 0.72rem;
            color: var(--color-text-faint);
        }

        .bin-value {
            font-family: 'JetBrains Mono', 'Courier New', monospace;
            font-size: 0.75rem;
            letter-spacing: 0.02em;
            word-break: break-all;
        }

        .bin-net  { color: var(--color-accent-light); }
        .bin-host { color: var(--color-text-faint); }

        .bin-v6 { font-size: 0.65rem; letter-spacing: 0; }

        .bin-boundary {
            font-size: 0.72rem;
            color: var(--color-text-faint);
            text-align: center;
            padding-bottom: 0.5rem;
        }

        /* Subnet splitter */
        .splitter {
            margin-top: 1rem;
            border: 1px solid var(--color-border);
            border-radius: 8px;
            overflow: hidden;
        }

        .splitter-title {
            background: var(--color-input-bg);
            color: var(--color-text-muted);
            font-size: 0.7rem;
            font-weight: 700;
            letter-spacing: 0.08em;
            padding: 0.6rem 1rem;
            text-transform: uppercase;
        }

        .splitter-form {
            padding: 0.75rem 1rem;
            border-top: 1px solid var(--color-border);
            background: var(--color-surface-alt);
        }

        .splitter-row {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            flex-wrap: wrap;
        }

        .splitter-label {
            color: var(--color-text-subtle);
            font-size: 0.8rem;
            flex-shrink: 0;
        }

        .splitter-input {
            width: 80px !important;
        }

        .splitter-btn {
            background: var(--color-surface);
            border: 1px solid var(--color-border);
            border-radius: 6px;
            color: var(--color-text-subtle);
            cursor: pointer;
            font-size: 0.85rem;
            font-weight: 600;
            padding: 0.45rem 0.75rem;
            transition: background 0.15s, color 0.15s;
            white-space: nowrap;
        }

        .splitter-btn:hover { background: var(--color-border); color: var(--color-text); }
        .splitter .error { margin: 0.75rem 1rem; }
        .form-group-narrow { max-width: 120px; }

        .split-list {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 0.4rem;
            padding: 0.75rem 1rem;
            border-top: 1px solid var(--color-border);
            background: var(--color-surface-alt);
        }

        .split-item {
            align-items: center;
            background: var(--color-surface);
            border: 1px solid var(--color-border);
            border-radius: 4px;
            color: var(--color-accent-light);
            cursor: pointer;
            display: flex;
            font-family: 'JetBrains Mono', 'Courier New', monospace;
            font-size: 0.78rem;
            justify-content: space-between;
            padding: 0.3rem 0.4rem 0.3rem 0.5rem;
            transition: background 0.1s;
        }

        .split-subnet-text { flex: 1; text-align: center; }

        .subnet-copy {
            background: none;
            border: none;
            color: var(--color-text-faint);
            cursor: pointer;
            display: flex;
            align-items: center;
            padding: 0 0 0 0.3rem;
            opacity: 50%;
            transition: opacity 0.15s, color 0.15s;
        }

        .split-item:hover .subnet-copy,
        .subnet-copy:focus-visible { opacity: 100%; color: var(--color-accent); }

        .subnet-copy:focus-visible { outline: 2px solid var(--color-accent); outline-offset: 1px; border-radius: 2px; }

        .split-item:hover { background: var(--color-border); }

        .result-row:focus-visible {
            outline: 2px solid var(--color-accent);
            outline-offset: -2px;
            background: var(--color-border) !important;
        }

        .split-item:focus-visible {
            outline: 2px solid var(--color-accent);
            outline-offset: -1px;
        }

        .split-more {
            color: var(--color-text-faint);
            font-size: 0.75rem;
            grid-column: 1 / -1;
            text-align: center;
            padding: 0.15rem 0;
        }

        button:focus-visible,
        a.btn:focus-visible {
            outline: 2px solid var(--color-accent);
            outline-offset: 2px;
        }

        /* VLSM planner */
        .vlsm-form { margin-bottom: 0.75rem; }

        .vlsm-reqs { margin-bottom: 0.5rem; }

        .vlsm-reqs-header {
            display: flex;
            gap: 0.5rem;
            font-size: 0.72rem;
            color: var(--color-text-faint);
            padding: 0 2rem 0.2rem 0;
        }

        .vlsm-col-name  { flex: 1.5; }
        .vlsm-col-hosts { flex: 1; }

        .vlsm-req-row {
            display: flex;
            gap: 0.5rem;
            align-items: center;
            margin-bottom: 0.35rem;
        }

        .vlsm-name-input  { flex: 1.5; }
        .vlsm-hosts-input { flex: 1; }

        .vlsm-remove-row {
            background: none;
            border: none;
            color: var(--color-text-faint);
            cursor: pointer;
            font-size: 1.1rem;
            padding: 0 0.2rem;
            line-height: 1;
        }

        .vlsm-remove-row:hover { color: var(--color-text); }

        .vlsm-actions {
            display: flex;
            gap: 0.5rem;
            align-items: center;
        }

        .vlsm-add-row {
            background: none;
            border: 1px solid var(--color-border);
            border-radius: 4px;
            color: var(--color-accent);
            cursor: pointer;
            font-size: 0.78rem;
            padding: 0.3rem 0.65rem;
            transition: background 0.1s;
        }

        .vlsm-add-row:hover { background: var(--color-border); }

        .vlsm-results { margin-top: 0.75rem; overflow-x: auto; }

        .vlsm-sort-note {
            font-size: 0.75rem;
            color: var(--color-text-faint);
            margin-bottom: 0.4rem;
        }

        .vlsm-table {
            border-collapse: collapse;
            width: 100%;
            font-size: 0.8rem;
        }

        .vlsm-table th {
            text-align: left;
            padding: 0.3rem 0.5rem;
            border-bottom: 1px solid var(--color-border);
            color: var(--color-text-faint);
            font-weight: 500;
            white-space: nowrap;
        }

        .vlsm-table td {
            padding: 0.3rem 0.5rem;
            border-bottom: 1px solid var(--color-border);
        }

        .vlsm-subnet-cell {
            cursor: pointer;
            font-family: 'JetBrains Mono', 'Courier New', monospace;
        }

        .vlsm-subnet-cell:hover { background: var(--color-border); }

        .vlsm-waste { color: var(--color-text-faint); }

        .copy-all-btn {
            background: none;
            border: 1px solid var(--color-border);
            border-radius: 4px;
            color: var(--color-text-subtle);
            cursor: pointer;
            font-size: 0.72rem;
            font-weight: 600;
            padding: 0.2rem 0.5rem;
            margin: 0.3rem 0;
            grid-column: 1 / -1;
            transition: background 0.15s, color 0.15s;
        }
        .copy-all-btn:hover { background: var(--color-border); color: var(--color-text); }

        .vlsm-summary {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem 1rem;
            margin-top: 0.5rem;
            font-size: 0.78rem;
            color: var(--color-text-subtle);
        }
        .vlsm-summary strong { color: var(--color-accent-light); }

        .export-btn-group {
            display: flex;
            flex-wrap: wrap;
            gap: 0.35rem;
            margin-top: 0.4rem;
        }
        .export-btn-group button {
            background: none;
            border: 1px solid var(--color-border);
            border-radius: 4px;
            color: var(--color-text-subtle);
            cursor: pointer;
            font-size: 0.72rem;
            font-weight: 600;
            padding: 0.2rem 0.5rem;
            transition: background 0.15s, color 0.15s;
        }
        .export-btn-group button:hover { background: var(--color-border); color: var(--color-text); }

        .vlsm-inline-error {
            color: var(--color-error-text, #e05252);
            font-size: 0.72rem;
            display: block;
            margin-top: 0.15rem;
        }

        /* Overlap checker */
        .overlap-panel {
            margin-top: 1rem;
            border: 1px solid var(--color-border);
            border-radius: 6px;
            padding: 0.65rem 0.75rem;
        }

        .overlap-title {
            font-size: 0.78rem;
            font-weight: 600;
            color: var(--color-text-faint);
            margin-bottom: 0.5rem;
            text-transform: uppercase;
            letter-spacing: 0.04em;
        }

        .session-ttl-notice { font-size: 0.8rem; color: var(--color-text-muted); margin: 0.25rem 0 0.5rem; }

        .session-forms { display: flex; flex-direction: column; gap: 1rem; }

        /* ── Help bubbles ─────────────────────────────────────────────────── */
        .help-bubble { position: relative; display: inline-flex; align-items: center; }
        .help-bubble-icon {
            display: inline-flex; align-items: center; justify-content: center;
            width: 18px; height: 18px; border-radius: 50%;
            background: var(--color-border); color: var(--color-text-subtle);
            font-size: 0.7rem; font-weight: 700; line-height: 1;
            cursor: help; margin-left: 0.3rem; flex-shrink: 0;
            padding: 3px;
        }
        .help-bubble-text {
            position: absolute; bottom: calc(100% + 6px); left: 50%;
            transform: translateX(-50%);
            width: 260px; max-width: min(260px, calc(100vw - 2rem));
            background: var(--color-surface-alt); border: 1px solid var(--color-border);
            border-radius: 6px; padding: 0.45rem 0.6rem;
            font-size: 0.76rem; line-height: 1.45; z-index: 200;
            color: var(--color-text);      /* #205: don't inherit badge/label colours */
            text-transform: none;          /* #205: don't inherit label uppercase */
            font-weight: normal;           /* #205: don't inherit label bold */
            letter-spacing: normal;        /* #205: don't inherit label letter-spacing */
            visibility: hidden; opacity: 0%; transition: opacity 0.15s;
            pointer-events: none;
        }
        .help-bubble:hover .help-bubble-text,
        .help-bubble:focus-within .help-bubble-text { visibility: visible; opacity: 100%; }

        /* #205: right-edge overflow fix — flip alignment when near viewport edge */
        .bubble-right-edge .help-bubble-text {
            left: auto;
            right: 0;
            transform: none;
        }

        /* #205: label bubbles appear below the label so they don't overlap
           the card title / tabs above the form */
        label .help-bubble-text {
            bottom: auto;
            top: calc(100% + 6px);
        }

        /* #205: section-header bubbles appear below the trigger so they don't
           overlap the card/content immediately above the panel title */
        .overlap-title .help-bubble-text {
            bottom: auto;
            top: calc(100% + 6px);
        }

        /* ── CSP fix: classes replacing inline style= attributes (#206) ─────── */

        /* Supernet action row (Find Supernet + Summarise buttons) */
        .supernet-action-row { margin-top: 0.5rem; }

        /* Generic top margin for result split-lists */
        .split-list--mt { margin-top: 0.5rem; }

        /* Tree: form group bottom margin */
        .tree-form-group { margin-bottom: 0.5rem; }

        /* Tree: parent CIDR label (smaller, muted colour) */
        .tree-parent-label { font-size: 0.8rem; color: var(--color-text-faint); }

        /* Tree: submit button wrapper */
        .tree-action-row { margin-top: 0.5rem; }

        /* Tree: result view */
        .tree-view { margin-top: 0.5rem; }

        /* Tree: individual node row */
        .tree-node { font-size: 0.85rem; margin: 0.15rem 0; }

        /* Tree: unallocated gap node */
        .tree-gap { color: var(--color-text-faint); font-style: italic; }

        /* Tree: "(free)" annotation inside gap nodes */
        .tree-free-label { font-size: 0.75rem; }

        /* ULA: form row (align button to baseline of input) */
        .ula-form-row { align-items: flex-end; gap: 0.5rem; }

        /* ULA: footnote text inside a label (optional global ID hint) */
        .label-footnote { font-weight: normal; font-size: 0.85em; }

        /* ULA: generate button wrapper (small bottom offset) */
        .ula-generate-wrap { padding-bottom: 0.1rem; }

        /* Session: saved-link bar bottom margin */
        .session-saved-bar { margin-bottom: 0.5rem; }

        .overlap-inputs {
            display: flex;
            align-items: center;
            gap: 0.4rem;
            flex-wrap: wrap;
        }

        .overlap-inputs input { flex: 1; min-width: 8rem; }

        .overlap-vs {
            font-size: 0.78rem;
            color: var(--color-text-faint);
            white-space: nowrap;
        }

        .overlap-result {
            margin-top: 0.5rem;
            font-size: 0.82rem;
            padding: 0.3rem 0.5rem;
            border-radius: 4px;
        }

        .overlap-none     { color: var(--color-text-faint); }
        .overlap-identical { color: var(--color-accent); font-weight: 600; }
        .overlap-contains { color: #e5a23a; font-weight: 600; }

        .multi-overlap-panel { margin-top: 0.75rem; }

        .multi-overlap-input {
            width: 100%;
            background: var(--color-input-bg);
            border: 1px solid var(--color-border);
            border-radius: 6px;
            color: var(--color-input-text);
            font-family: 'JetBrains Mono', 'Courier New', monospace;
            font-size: 0.85rem;
            padding: 0.5rem 0.75rem;
            resize: vertical;
            margin-bottom: 0.5rem;
            display: block;
        }

        .multi-overlap-list {
            list-style: none;
            margin-top: 0.5rem;
            padding: 0;
            font-size: 0.82rem;
        }
        .multi-overlap-list li {
            padding: 0.25rem 0;
            border-bottom: 1px solid var(--color-border);
        }
        .multi-overlap-list li:last-child { border-bottom: none; }

        .ula-meta {
            margin-top: 0.35rem;
            font-size: 0.82rem;
            display: flex;
            gap: 1rem;
            flex-wrap: wrap;
            color: var(--color-text-faint);
        }
        .ula-meta code { font-family: 'JetBrains Mono', 'Courier New', monospace; color: var(--color-text); }

        @media (width <= 480px) {
            .form-row { flex-direction: column; }
            .split-list { grid-template-columns: 1fr; }
        }

        @media (481px <= width <= 767px) {
            .card { padding: 1.5rem 1.25rem; }
        }

        @media (width >= 900px) {
            .card { max-width: 800px; }
        }

        /* Scroll affordance: right-edge gradient fade on narrow viewports */
        @media (width <= 767px) {
            .vlsm-results,
            .split-list-scroll {
                position: relative;
            }
            .vlsm-results::after,
            .split-list-scroll::after {
                content: '';
                position: absolute;
                top: 0;
                right: 0;
                width: 2.5rem;
                height: 100%;
                background: linear-gradient(to right, transparent, var(--color-surface));
                pointer-events: none;
                border-radius: 0 6px 6px 0;
            }
        }

        @media print {
            * { -webkit-print-color-adjust: exact; print-color-adjust: exact; }
            html, body, .card {
                background: #fff !important;
                color: #000 !important;
                box-shadow: none !important;
                border: none !important;
            }
            body { min-height: 0; }
            .tabs, .btn-row, .share-bar, .splitter-form,
            .theme-toggle, .version, footer, .toast { display: none !important; }
            .panel.active { display: block !important; }
            .card { padding: 0; max-width: 100%; }
            .result-row { border-bottom: 1px solid #ccc; }
            .badge { border: 1px solid #999; }
            .split-list { columns: 2; display: block; }

            /* #193: VLSM table — full width with repeating headers on page breaks */
            .vlsm-results { overflow-x: visible; }
            .vlsm-table { width: 100%; table-layout: fixed; overflow-wrap: anywhere; }
            .vlsm-table thead { display: table-header-group; }
            .vlsm-summary { break-inside: avoid; }

            /* #193: hide export/copy/share controls */
            .export-btn-group,
            .copy-all-btn,
            .ascii-export-btn { display: none !important; }
        }

        @media (prefers-reduced-motion: reduce) {
            *, *::before, *::after {
                animation-duration: 0.01ms !important;
                animation-iteration-count: 1 !important;
                transition-duration: 0.01ms !important;
                scroll-behavior: auto !important;
            }
        }

        html.in-iframe,
        html.in-iframe body {
            margin: 0;
            padding: 0;
            overflow: hidden;
        }
        html.in-iframe body {
            min-height: 0;
            align-items: flex-start;
        }