/* ───── reset additions ───── */
  body { background: var(--paper); color: var(--ink); overflow-x: hidden; }
  a { color: inherit; text-decoration: none; }
  button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }

  /* ───── layout ───── */
  .wrap { max-width: 1240px; margin: 0 auto; padding: 0 32px; }
  @media (max-width: 720px) { .wrap { padding: 0 20px; } }

  /* ───── nav ───── */
  nav.top {
    position: sticky; top: 0; z-index: 50;
    background: color-mix(in oklch, var(--paper) 88%, transparent);
    backdrop-filter: saturate(140%) blur(14px);
    -webkit-backdrop-filter: saturate(140%) blur(14px);
    border-bottom: 1px solid color-mix(in oklch, var(--hairline) 60%, transparent);
  }
  nav.top .inner {
    display: flex; align-items: center; justify-content: space-between;
    height: 64px;
  }
  .brand {
    display: flex; align-items: center; gap: 12px;
    font: 600 17px/1 var(--font-serif); letter-spacing: -0.01em;
  }
  .brand .mark {
    width: 28px; height: 28px; display: grid; place-items: center;
    background: var(--ink); color: var(--paper); border-radius: 7px;
  }
  .brand em { font-style: italic; color: var(--accent); font-weight: 500; }
  nav.top ul {
    list-style: none; display: flex; gap: 28px; padding: 0; margin: 0;
    font: 500 14px/1 var(--font-ui); color: var(--ink-2);
  }
  nav.top ul a:hover { color: var(--ink); }
  nav.top .right { display: flex; align-items: center; gap: 20px; }
  .langtog {
    display: inline-flex; align-items: center;
    font: 500 11px/1 var(--font-mono); color: var(--ink-3);
    letter-spacing: 0.04em;
    border: 1px solid var(--hairline);
    border-radius: 999px;
    padding: 5px 10px;
    transition: border-color var(--m-fast) var(--ease);
  }
  .langtog:hover { border-color: var(--rule); }
  .langtog .sep { color: var(--ink-4); margin: 0 6px; }
  .langtog .on { color: var(--ink); }
  @media (max-width: 800px) {
    nav.top ul { display: none; }
  }

  /* ───── hero ───── */
  .hero {
    padding: 96px 0 80px;
    display: grid;
    grid-template-columns: 1.05fr 1fr;
    gap: 80px;
    align-items: center;
  }
  @media (max-width: 1000px) {
    .hero { grid-template-columns: 1fr; gap: 56px; padding: 64px 0 40px; }
  }
  .hero .eyebrow {
    font: 600 12px/1 var(--font-ui); text-transform: uppercase;
    letter-spacing: 0.16em; color: var(--accent);
    display: inline-flex; align-items: center; gap: 10px;
    margin-bottom: 28px;
  }
  .hero .eyebrow .dash { width: 28px; height: 1px; background: var(--accent); display: inline-block; }
  .hero h1 {
    font: 600 clamp(48px, 7.2vw, 96px) / 0.96 var(--font-serif);
    letter-spacing: -0.028em;
    margin: 0 0 28px;
    color: var(--ink);
  }
  .hero h1 em {
    font-style: italic;
    color: var(--accent);
    font-weight: 500;
  }
  .hero .lead {
    font: 400 21px/1.55 var(--font-serif);
    color: var(--ink-2);
    margin: 0 0 36px;
    max-width: 520px;
    letter-spacing: -0.005em;
  }
  .hero .lead strong { color: var(--ink); font-weight: 600; }
  .ctas { display: flex; gap: 14px; flex-wrap: wrap; align-items: center; }
  .btn-primary {
    display: inline-flex; align-items: center; gap: 10px;
    padding: 14px 22px;
    background: var(--ink); color: var(--paper);
    border-radius: 999px;
    font: 600 15px/1 var(--font-ui);
    letter-spacing: -0.005em;
    transition: transform var(--m-fast) var(--ease), background var(--m-base) var(--ease);
  }
  .btn-primary:hover { transform: translateY(-1px); background: var(--accent-deep); }
  .btn-primary svg { width: 16px; height: 16px; }
  .btn-ghost {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 13px 18px;
    font: 500 14px/1 var(--font-ui);
    color: var(--ink-2);
    border: 1px solid var(--hairline);
    border-radius: 999px;
    transition: border-color var(--m-fast) var(--ease), color var(--m-fast) var(--ease);
  }
  .btn-ghost:hover { border-color: var(--rule); color: var(--ink); }
  .btn-ghost .play {
    width: 18px; height: 18px; border-radius: 999px;
    background: var(--accent); color: var(--paper);
    display: grid; place-items: center; font-size: 8px;
  }

  .hero-aside {
    position: relative;
    display: flex; align-items: center; justify-content: center;
  }

  /* ───── sudoku board (shared) ───── */
  .board {
    --cell: clamp(36px, 5.2vw, 54px);
    display: grid;
    grid-template-columns: repeat(9, var(--cell));
    grid-template-rows: repeat(9, var(--cell));
    background: var(--card);
    border-radius: var(--r-md);
    box-shadow: var(--shadow-2);
    padding: 14px;
    gap: 0;
    position: relative;
  }
  .board.compact { --cell: clamp(28px, 3.4vw, 36px); padding: 10px; border-radius: var(--r-sm); }
  .board.mini    { --cell: 24px; padding: 7px; border-radius: var(--r-sm); }

  .cell {
    position: relative;
    display: grid; place-items: center;
    font: 500 var(--t-digit)/1 var(--font-round);
    color: var(--given-text);
    border-right: 1px solid var(--grid-line);
    border-bottom: 1px solid var(--grid-line);
    transition: background var(--m-fast) var(--ease), color var(--m-fast) var(--ease);
    user-select: none;
  }
  .board.compact .cell { font-size: 17px; }
  .board.mini    .cell { font-size: 12px; font-weight: 500; }
  .cell.col2, .cell.col5 { border-right: 1.5px solid var(--grid-box); }
  .cell.row2, .cell.row5 { border-bottom: 1.5px solid var(--grid-box); }
  .cell.col8 { border-right: 0; }
  .cell.row8 { border-bottom: 0; }
  .cell.user { color: var(--user-text); }
  .cell.selected { background: var(--accent-soft); color: var(--accent-deep); }
  .cell.peer { background: var(--accent-softer); }
  .cell.same-val { background: var(--accent-medium); }
  .cell.coach { background: var(--coach-soft); box-shadow: inset 0 0 0 2px var(--coach); border-radius: 6px; z-index: 2; }
  .cell.mistake { color: var(--mistake-text); animation: shake 0.32s var(--ease); }
  .cell.placed { animation: cellPop 0.32s var(--ease); }
  .cell .pencil {
    position: absolute; inset: 4px;
    display: grid; grid-template-columns: repeat(3, 1fr); grid-template-rows: repeat(3, 1fr);
    font: 500 9px/1 var(--font-round); color: var(--pencil-text);
  }
  .cell .pencil span { display: grid; place-items: center; }

  @keyframes cellPop {
    0% { transform: scale(0.6); opacity: 0; }
    60% { transform: scale(1.08); opacity: 1; }
    100% { transform: scale(1); opacity: 1; }
  }
  @keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-3px); }
    50% { transform: translateX(3px); }
    75% { transform: translateX(-2px); }
  }

  /* hero board frame */
  .hero-frame {
    position: relative;
    padding: 16px;
    background: linear-gradient(180deg, var(--paper-2), var(--paper));
    border-radius: 28px;
    box-shadow: var(--shadow-2);
    border: 1px solid var(--hairline);
  }
  .hero-frame::before {
    content: "";
    position: absolute; inset: -120px -120px auto auto;
    width: 360px; height: 360px;
    background: radial-gradient(circle at center, oklch(0.620 0.105 72 / 0.18), transparent 60%);
    z-index: -1; pointer-events: none;
    border-radius: 50%;
    filter: blur(40px);
  }
  .hero-frame .meta {
    display: flex; justify-content: space-between; align-items: center;
    padding: 0 6px 12px;
    font: 500 11px/1 var(--font-mono); letter-spacing: 0.06em;
    color: var(--ink-3); text-transform: uppercase;
  }
  .hero-frame .meta .dot {
    display: inline-block; width: 6px; height: 6px; border-radius: 50%;
    background: var(--success); margin-right: 6px;
    animation: pulse 2s ease-in-out infinite;
  }
  @keyframes pulse {
    0%, 100% { opacity: 0.6; }
    50% { opacity: 1; }
  }
  .hero-frame .timer { color: var(--ink); font-variant-numeric: tabular-nums; }

  /* ───── stat strip ───── */
  .stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0;
    border-top: 1px solid var(--hairline);
    border-bottom: 1px solid var(--hairline);
    margin: 32px 0 96px;
  }
  @media (max-width: 720px) { .stats { grid-template-columns: repeat(2, 1fr); } }
  .stats .stat {
    padding: 28px 24px;
    border-right: 1px solid var(--hairline);
  }
  .stats .stat:last-child { border-right: 0; }
  @media (max-width: 720px) {
    .stats .stat:nth-child(2n) { border-right: 0; }
    .stats .stat:nth-child(-n+2) { border-bottom: 1px solid var(--hairline); }
  }
  .stats .stat .num {
    font: 600 36px/1 var(--font-serif); letter-spacing: -0.02em;
    color: var(--ink);
    display: block; margin-bottom: 8px;
  }
  .stats .stat .num em { color: var(--accent); font-style: italic; font-weight: 500; }
  .stats .stat .lbl {
    font: 500 12px/1.3 var(--font-ui); color: var(--ink-3);
    text-transform: uppercase; letter-spacing: 0.1em;
  }

  /* ───── section header ───── */
  .sect-head {
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 24px;
    align-items: baseline;
    margin-bottom: 56px;
  }
  .sect-head .num {
    font: 500 12px/1 var(--font-mono); color: var(--ink-3);
    letter-spacing: 0.08em;
  }
  .sect-head h2 {
    font: 600 clamp(32px, 4vw, 48px) / 1.05 var(--font-serif);
    letter-spacing: -0.022em;
    color: var(--ink);
    margin: 0;
  }
  .sect-head h2 em { font-style: italic; color: var(--accent); font-weight: 500; }
  .sect-head .aside {
    font: 400 16px/1.5 var(--font-serif);
    color: var(--ink-2);
    max-width: 360px;
    text-align: right;
    letter-spacing: -0.005em;
  }
  @media (max-width: 720px) {
    .sect-head { grid-template-columns: 1fr; gap: 12px; }
    .sect-head .aside { text-align: left; }
  }

  section { padding: 80px 0; }
  section.tight { padding: 56px 0; }

  /* ───── pillars ───── */
  .pillars {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1px;
    background: var(--hairline);
    border: 1px solid var(--hairline);
    border-radius: var(--r-lg);
    overflow: hidden;
  }
  @media (max-width: 720px) { .pillars { grid-template-columns: 1fr; } }
  .pillar {
    background: var(--paper);
    padding: 40px;
    position: relative;
    transition: background var(--m-base) var(--ease);
  }
  .pillar:hover { background: var(--paper-2); }
  .pillar .ico {
    width: 56px; height: 56px;
    display: grid; place-items: center;
    background: var(--ink);
    color: var(--paper);
    border-radius: 14px;
    margin-bottom: 24px;
    transition: background var(--m-base) var(--ease), color var(--m-base) var(--ease);
  }
  .pillar:hover .ico { background: var(--accent); }
  .pillar h3 {
    font: 600 22px/1.25 var(--font-serif);
    letter-spacing: -0.012em;
    margin: 0 0 10px;
  }
  .pillar p {
    font: 400 15px/1.55 var(--font-ui);
    color: var(--ink-2);
    margin: 0 0 24px;
    max-width: 380px;
  }
  .pillar .demo {
    margin-top: 16px;
    height: 130px;
    display: flex; align-items: center; justify-content: center;
    background: var(--paper-2);
    border-radius: var(--r-sm);
    border: 1px solid var(--hairline);
    overflow: hidden;
    position: relative;
  }
  .pillar:hover .demo { background: var(--card); }

  /* technique chip (for "solver that teaches") */
  .technique-chip {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 6px 12px;
    background: var(--coach-soft);
    color: var(--coach);
    border-radius: 999px;
    font: 500 12px/1 var(--font-mono);
    letter-spacing: 0.02em;
    border: 1px solid color-mix(in oklch, var(--coach) 30%, transparent);
  }
  .technique-chip .bullet {
    width: 5px; height: 5px; border-radius: 50%;
    background: var(--coach);
  }

  /* ───── variants ───── */
  .variants {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
  }
  @media (max-width: 1000px) { .variants { grid-template-columns: repeat(2, 1fr); } }
  @media (max-width: 600px)  { .variants { grid-template-columns: 1fr; } }
  .variant {
    background: var(--card);
    border: 1px solid var(--hairline);
    border-radius: var(--r-lg);
    padding: 28px;
    transition: transform var(--m-base) var(--ease), box-shadow var(--m-base) var(--ease), border-color var(--m-base) var(--ease);
    cursor: pointer;
    position: relative;
  }
  .variant:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-2);
    border-color: var(--rule);
  }
  .variant .preview {
    height: 200px;
    background: var(--paper-2);
    border-radius: var(--r-sm);
    border: 1px solid var(--hairline);
    display: grid; place-items: center;
    margin-bottom: 24px;
    position: relative;
    overflow: hidden;
  }
  .variant .topline {
    display: flex; justify-content: space-between; align-items: center;
    margin-bottom: 12px;
  }
  .variant .name {
    font: 600 19px/1.25 var(--font-serif);
    letter-spacing: -0.012em;
  }
  .variant .badge-classic {
    font: 500 11px/1 var(--font-mono);
    color: var(--ink-3);
    letter-spacing: 0.08em;
    text-transform: uppercase;
  }
  .variant .badge-premium {
    display: inline-flex; align-items: center; gap: 5px;
    font: 500 11px/1 var(--font-mono);
    color: var(--gold-deep);
    letter-spacing: 0.08em;
    text-transform: uppercase;
  }
  .variant .badge-premium::before {
    content: ""; width: 6px; height: 6px; border-radius: 50%;
    background: var(--gold);
  }
  .variant p {
    font: 400 14px/1.55 var(--font-ui);
    color: var(--ink-2);
    margin: 0;
  }

  /* mini board styling per variant */
  .vboard {
    display: grid;
    grid-template-columns: repeat(9, 14px);
    grid-template-rows: repeat(9, 14px);
    background: var(--card);
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
    border-radius: 4px;
    padding: 6px;
  }
  .vcell {
    border-right: 0.5px solid var(--grid-line);
    border-bottom: 0.5px solid var(--grid-line);
    display: grid; place-items: center;
    font: 500 9px/1 var(--font-round);
    color: var(--given-text);
    position: relative;
  }
  .vcell.vcol2, .vcell.vcol5 { border-right: 1px solid var(--grid-box); }
  .vcell.vrow2, .vcell.vrow5 { border-bottom: 1px solid var(--grid-box); }
  .vcell.vcol8 { border-right: 0; }
  .vcell.vrow8 { border-bottom: 0; }
  .vcell.user-v { color: var(--user-text); }

  /* X-Sudoku diagonal shading */
  .vboard.x-sudoku .vcell.diag { background: color-mix(in oklch, var(--accent-softer) 70%, transparent); }
  /* Hyper extra boxes */
  .vboard.hyper .vcell.hyperbox { background: color-mix(in oklch, var(--gold-soft) 60%, transparent); }
  /* Killer cage indicators */
  .vboard.killer .vcell.cage-tl::before {
    content: attr(data-sum);
    position: absolute; top: 1px; left: 2px;
    font: 500 6px/1 var(--font-mono); color: var(--ink-3);
  }
  .vboard.killer .vcell.cage { background: color-mix(in oklch, var(--paper-2) 50%, transparent); }

  /* Sandwich outer clues */
  .sandwich-wrap {
    display: grid;
    grid-template-columns: 14px auto;
    gap: 2px;
    align-items: center;
  }
  .sandwich-col-clues {
    grid-column: 2; display: grid; grid-template-columns: repeat(9, 14px);
    padding-left: 6px;
    font: 500 8px/1 var(--font-mono); color: var(--gold-deep);
    margin-bottom: 2px;
  }
  .sandwich-col-clues span, .sandwich-row-clues span { display: grid; place-items: center; }
  .sandwich-row-clues {
    grid-row: 2; grid-column: 1;
    display: grid; grid-template-rows: repeat(9, 14px);
    padding-top: 6px;
    font: 500 8px/1 var(--font-mono); color: var(--gold-deep);
    margin-right: 2px;
  }

  /* ───── live playable ───── */
  .live-wrap {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 64px;
    align-items: center;
  }
  @media (max-width: 1000px) {
    .live-wrap { grid-template-columns: 1fr; gap: 40px; }
  }
  .live-side {
    max-width: 440px;
  }
  .live-side .kicker {
    font: 500 12px/1 var(--font-mono); color: var(--accent);
    text-transform: uppercase; letter-spacing: 0.12em;
    margin-bottom: 20px;
  }
  .live-side h3 {
    font: 600 36px/1.05 var(--font-serif);
    letter-spacing: -0.022em;
    margin: 0 0 18px;
  }
  .live-side p { font: 400 17px/1.55 var(--font-serif); color: var(--ink-2); margin: 0 0 28px; letter-spacing: -0.003em; }
  .live-controls { display: flex; flex-direction: column; gap: 16px; }
  .live-coach {
    background: var(--coach-soft);
    border: 1px solid color-mix(in oklch, var(--coach) 40%, transparent);
    padding: 18px 20px;
    border-radius: var(--r-md);
    min-height: 92px;
    position: relative;
  }
  .live-coach .head {
    display: flex; align-items: center; gap: 10px;
    font: 600 11px/1 var(--font-mono); color: var(--coach);
    text-transform: uppercase; letter-spacing: 0.08em;
    margin-bottom: 10px;
  }
  .live-coach .head::before {
    content: ""; width: 6px; height: 6px; border-radius: 50%;
    background: var(--coach);
  }
  .live-coach .body {
    font: 400 15px/1.5 var(--font-serif);
    color: var(--ink);
    letter-spacing: -0.003em;
  }
  .live-coach .body em { color: var(--coach); font-style: italic; font-weight: 500; }
  .live-coach.idle .body { color: var(--ink-3); font-style: italic; }
  .live-coach .loading { display: inline-flex; gap: 4px; }
  .live-coach .loading span {
    width: 5px; height: 5px; border-radius: 50%;
    background: var(--coach);
    animation: dot 1.4s infinite ease-in-out;
  }
  .live-coach .loading span:nth-child(2) { animation-delay: 0.16s; }
  .live-coach .loading span:nth-child(3) { animation-delay: 0.32s; }
  @keyframes dot {
    0%, 80%, 100% { opacity: 0.3; transform: scale(0.8); }
    40% { opacity: 1; transform: scale(1.1); }
  }
  .live-actions { display: flex; gap: 10px; flex-wrap: wrap; }
  .pill-btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 11px 16px;
    border: 1px solid var(--hairline);
    border-radius: 999px;
    font: 500 14px/1 var(--font-ui);
    background: var(--card);
    color: var(--ink);
    transition: border-color var(--m-fast) var(--ease), background var(--m-fast) var(--ease);
  }
  .pill-btn:hover { border-color: var(--rule); background: var(--paper-2); }
  .pill-btn.primary { background: var(--accent); color: var(--on-accent); border-color: var(--accent); }
  .pill-btn.primary:hover { background: var(--accent-deep); border-color: var(--accent-deep); }

  /* number pad below board */
  .live-stack { display: flex; flex-direction: column; gap: 18px; align-items: center; }
  .numpad {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    gap: 6px;
    width: 100%;
    max-width: 540px;
  }
  .numpad button {
    aspect-ratio: 1;
    border-radius: var(--r-sm);
    background: var(--card);
    border: 1px solid var(--hairline);
    font: 500 22px/1 var(--font-round);
    color: var(--ink);
    transition: all var(--m-fast) var(--ease);
  }
  .numpad button:hover { background: var(--accent-soft); border-color: var(--accent); color: var(--accent-deep); }
  .numpad button.exhausted { opacity: 0.3; pointer-events: none; }

  /* ───── race ───── */
  .race {
    background: var(--ink);
    color: var(--paper);
    border-radius: var(--r-xl);
    padding: 64px 56px;
    position: relative;
    overflow: hidden;
  }
  @media (max-width: 720px) { .race { padding: 40px 24px; } }
  .race::before {
    content: "";
    position: absolute; inset: 0;
    background:
      radial-gradient(circle at 20% 30%, oklch(0.700 0.075 185 / 0.15), transparent 50%),
      radial-gradient(circle at 80% 70%, oklch(0.620 0.105 72 / 0.10), transparent 50%);
    pointer-events: none;
  }
  .race h3 {
    font: 600 42px/1.05 var(--font-serif);
    letter-spacing: -0.02em;
    margin: 0 0 18px;
    color: var(--paper);
    max-width: 560px;
  }
  .race h3 em { color: oklch(0.700 0.075 185); font-style: italic; font-weight: 500; }
  .race .lead {
    font: 400 17px/1.55 var(--font-serif);
    color: oklch(0.800 0.008 85);
    max-width: 540px;
    margin: 0 0 56px;
    letter-spacing: -0.003em;
  }
  .race-arena {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 56px;
    align-items: center;
    position: relative;
  }
  @media (max-width: 760px) { .race-arena { grid-template-columns: 1fr; gap: 32px; } }
  .racer { text-align: center; }
  .racer .who {
    display: flex; align-items: center; justify-content: center; gap: 12px;
    margin-bottom: 18px;
  }
  .racer .avatar {
    width: 28px; height: 28px;
    border-radius: 50%;
    display: grid; place-items: center;
    font: 600 12px/1 var(--font-ui);
    color: var(--paper);
  }
  .racer.you .avatar  { background: oklch(0.700 0.075 185); color: var(--ink); }
  .racer.them .avatar { background: oklch(0.620 0.105 72); color: var(--ink); }
  .racer .name { font: 500 14px/1 var(--font-ui); color: oklch(0.800 0.008 85); }
  .racer .time { font: 500 12px/1 var(--font-mono); color: oklch(0.620 0.010 85); margin-left: auto; }

  .racer .mini-board-wrap {
    display: inline-block;
    background: var(--paper);
    color: var(--ink);
    padding: 12px;
    border-radius: var(--r-md);
    box-shadow: 0 8px 24px rgba(0,0,0,0.4);
  }
  .racer .progress {
    margin-top: 18px;
    height: 4px; background: oklch(0.300 0.010 250);
    border-radius: 2px; overflow: hidden;
    max-width: 240px; margin-left: auto; margin-right: auto;
  }
  .racer .progress .bar {
    height: 100%;
    transition: width 0.6s var(--ease);
  }
  .racer.you  .progress .bar { background: oklch(0.700 0.075 185); }
  .racer.them .progress .bar { background: oklch(0.620 0.105 72); }
  .racer .meta-row {
    display: flex; justify-content: space-between;
    max-width: 240px; margin: 10px auto 0;
    font: 500 11px/1 var(--font-mono); color: var(--ink-3);
  }
  .vs {
    position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%);
    width: 56px; height: 56px;
    background: var(--paper);
    color: var(--ink);
    border-radius: 50%;
    display: grid; place-items: center;
    font: 600 14px/1 var(--font-serif); font-style: italic;
    box-shadow: 0 4px 12px rgba(0,0,0,0.5);
    z-index: 3;
  }
  @media (max-width: 760px) { .vs { display: none; } }

  /* mini board used in race (smaller; 9x9 stylized) */
  .mboard {
    display: grid;
    grid-template-columns: repeat(9, 20px);
    grid-template-rows: repeat(9, 20px);
    background: var(--card);
    padding: 0;
  }
  .mcell {
    border-right: 0.5px solid var(--grid-line);
    border-bottom: 0.5px solid var(--grid-line);
    display: grid; place-items: center;
    font: 500 11px/1 var(--font-round);
    color: var(--given-text);
  }
  .mcell.mcol2, .mcell.mcol5 { border-right: 1.2px solid var(--grid-box); }
  .mcell.mrow2, .mcell.mrow5 { border-bottom: 1.2px solid var(--grid-box); }
  .mcell.mcol8 { border-right: 0; }
  .mcell.mrow8 { border-bottom: 0; }
  .mcell.user-m { color: var(--user-text); }
  .mcell.fresh { animation: cellPop 0.35s var(--ease); }

  /* ───── themes ───── */
  .themes {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 64px;
    align-items: center;
  }
  @media (max-width: 1000px) { .themes { grid-template-columns: 1fr; } }
  .theme-side h3 {
    font: 600 36px/1.05 var(--font-serif);
    letter-spacing: -0.022em;
    margin: 0 0 18px;
  }
  .theme-side p {
    font: 400 17px/1.55 var(--font-serif);
    color: var(--ink-2);
    margin: 0 0 32px;
    max-width: 420px;
  }
  .theme-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    max-width: 380px;
  }
  .theme-chip {
    display: flex; align-items: center; gap: 14px;
    padding: 14px 16px;
    border: 1px solid var(--hairline);
    border-radius: var(--r-sm);
    text-align: left;
    transition: border-color var(--m-fast) var(--ease), background var(--m-fast) var(--ease);
    cursor: pointer;
    background: var(--card);
  }
  .theme-chip:hover { border-color: var(--rule); }
  .theme-chip.active {
    border-color: var(--accent);
    background: var(--accent-softer);
  }
  .theme-chip .sw {
    width: 28px; height: 28px;
    border-radius: var(--r-sm);
    flex-shrink: 0;
    border: 1px solid color-mix(in oklch, var(--ink) 15%, transparent);
    position: relative; overflow: hidden;
  }
  .theme-chip .sw .a {
    position: absolute; bottom: 0; right: 0; width: 55%; height: 55%;
  }
  .theme-chip .label {
    font: 500 14px/1.2 var(--font-ui);
    color: var(--ink);
  }
  .theme-chip .label .sub {
    display: block; font-size: 11px; color: var(--ink-3);
    margin-top: 2px; font-family: var(--font-mono);
    text-transform: uppercase; letter-spacing: 0.05em;
  }

  .theme-preview {
    display: grid; place-items: center;
    padding: 40px;
    background: var(--paper-2);
    border-radius: var(--r-xl);
    border: 1px solid var(--hairline);
    transition: background var(--m-base) var(--ease), border-color var(--m-base) var(--ease);
  }
  /* preview cell smaller so it fits */
  .theme-preview .board {
    --cell: clamp(28px, 3.4vw, 38px);
    padding: 12px;
  }
  .theme-preview .board .cell { font-size: 16px; }

  .dark-toggle {
    display: flex; align-items: center; gap: 12px;
    margin-top: 20px;
    font: 500 13px/1 var(--font-ui); color: var(--ink-2);
  }
  .dark-toggle button {
    width: 44px; height: 24px;
    border-radius: 999px;
    background: var(--hairline);
    position: relative;
    transition: background var(--m-base) var(--ease);
  }
  .dark-toggle button::after {
    content: "";
    position: absolute; top: 3px; left: 3px;
    width: 18px; height: 18px;
    background: var(--card);
    border-radius: 50%;
    transition: transform var(--m-base) var(--ease);
    box-shadow: 0 1px 2px rgba(0,0,0,0.2);
  }
  .dark-toggle button.on { background: var(--accent); }
  .dark-toggle button.on::after { transform: translateX(20px); }

  /* ───── privacy band ───── */
  .privacy {
    text-align: center;
    padding: 120px 0;
    border-top: 1px solid var(--hairline);
    border-bottom: 1px solid var(--hairline);
  }
  .privacy .big {
    font: 600 clamp(80px, 14vw, 200px) / 0.85 var(--font-serif);
    letter-spacing: -0.04em;
    color: var(--ink);
    margin: 0 0 24px;
  }
  .privacy .big em { color: var(--accent); font-style: italic; font-weight: 500; }
  .privacy .sub {
    font: 400 21px/1.5 var(--font-serif);
    color: var(--ink-2);
    max-width: 540px;
    margin: 0 auto 36px;
    letter-spacing: -0.005em;
  }
  .privacy .breakdown {
    display: flex; justify-content: center; gap: 56px; flex-wrap: wrap;
    font: 500 12px/1.4 var(--font-mono); color: var(--ink-3);
    letter-spacing: 0.06em; text-transform: uppercase;
  }
  .privacy .breakdown div { display: flex; align-items: center; gap: 8px; }
  .privacy .breakdown div::before {
    content: ""; width: 14px; height: 1.5px; background: var(--accent);
  }

  /* ───── final CTA ───── */
  .final {
    padding: 120px 0;
    text-align: center;
  }
  .final h2 {
    font: 600 clamp(48px, 7vw, 88px) / 0.98 var(--font-serif);
    letter-spacing: -0.025em;
    margin: 0 0 24px;
  }
  .final h2 em { color: var(--accent); font-style: italic; font-weight: 500; }
  .final p {
    font: 400 19px/1.55 var(--font-serif);
    color: var(--ink-2);
    max-width: 460px;
    margin: 0 auto 36px;
  }

  /* ───── footer ───── */
  footer.site {
    border-top: 1px solid var(--hairline);
    padding: 56px 0 40px;
  }
  footer.site .row1 {
    display: grid; grid-template-columns: 1fr auto; gap: 32px;
    align-items: start; margin-bottom: 40px;
  }
  @media (max-width: 720px) { footer.site .row1 { grid-template-columns: 1fr; } }
  footer.site .col-links {
    display: grid; grid-template-columns: repeat(3, auto); gap: 56px;
    font: 500 13px/1.8 var(--font-ui);
  }
  @media (max-width: 720px) { footer.site .col-links { grid-template-columns: 1fr 1fr; gap: 24px; } }
  footer.site .col-links h4 {
    font: 600 11px/1.4 var(--font-mono);
    text-transform: uppercase; letter-spacing: 0.1em;
    color: var(--ink-3); margin: 0 0 12px;
  }
  footer.site .col-links a {
    color: var(--ink-2); display: block;
    transition: color var(--m-fast) var(--ease);
  }
  footer.site .col-links a:hover { color: var(--accent); }
  footer.site .colophon {
    border-top: 1px solid var(--hairline);
    padding-top: 24px;
    display: flex; justify-content: space-between; align-items: center;
    font: 500 12px/1.4 var(--font-mono);
    color: var(--ink-3);
    letter-spacing: 0.04em;
  }
  @media (max-width: 720px) { footer.site .colophon { flex-direction: column; gap: 12px; align-items: flex-start; } }

  /* ───── general utility ───── */
  .fade-in { opacity: 0; transform: translateY(16px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
  .fade-in.on { opacity: 1; transform: translateY(0); }