:root {
      --bg: #f3ecdf;
      --paper: rgba(255, 250, 240, 0.9);
      --ink: #1d2b2f;
      --muted: #54656a;
      --accent: #0d6a74;
      --accent-strong: #0b4c53;
      --soft: #dbece8;
      --line: rgba(29, 43, 47, 0.14);
      --shadow: 0 20px 56px rgba(72, 54, 24, 0.12);
      --panel-pad: 18px;
      --section-gap: 10px;
      --viz-2col-size: min(100%, 40vh);
      --viz-3col-size: min(100%, 24vh);
    }

    * {
      box-sizing: border-box;
    }

    html,
    body {
      margin: 0;
      height: 100%;
      min-height: 100vh;
      font-family: "Trebuchet MS", "Gill Sans", sans-serif;
      color: var(--ink);
      background:
        radial-gradient(circle at top left, rgba(211, 154, 94, 0.18), transparent 30%),
        radial-gradient(circle at bottom right, rgba(45, 125, 138, 0.16), transparent 26%),
        linear-gradient(140deg, #f7f1e5, #eee2cb 48%, #e7efec);
    }

    body {
      overflow: hidden;
    }

    .deck {
      height: 100vh;
      height: 100dvh;
      display: grid;
      grid-template-rows: minmax(0, 1fr) auto;
    }

    .slides {
      min-height: 0;
    }

    .slide {
      display: none;
      height: 100%;
      min-height: 0;
      padding: 16px 20px 10px;
      overflow: hidden;
    }

    .slide.active {
      display: flex;
      justify-content: center;
      align-items: flex-start;
    }

    .panel {
      max-width: 1280px;
      width: min(1280px, 100%);
      height: 100%;
      margin: 0 auto;
      padding: var(--panel-pad);
      border-radius: 24px;
      background: var(--paper);
      border: 1px solid rgba(255, 255, 255, 0.64);
      box-shadow: var(--shadow);
      backdrop-filter: blur(8px);
      overflow: hidden;
      display: flex;
      flex-direction: column;
      gap: var(--section-gap);
    }

    .panel > :last-child {
      flex: 1;
      min-height: 0;
    }

    h1, h2, h3, h4 {
      margin: 0 0 8px;
      font-family: Georgia, "Times New Roman", serif;
      letter-spacing: -0.03em;
      line-height: 1.03;
    }

    h1 {
      font-size: clamp(2.1rem, 4vw, 3.8rem);
    }

    h2 {
      font-size: clamp(1.7rem, 3vw, 2.7rem);
    }

    h3 {
      font-size: 1.02rem;
    }

    h4 {
      font-size: 0.92rem;
    }

    .title-with-count {
      display: flex;
      align-items: baseline;
      gap: 10px;
      flex-wrap: wrap;
    }

    .title-count {
      color: var(--accent-strong);
      font-family: "Trebuchet MS", "Gill Sans", sans-serif;
      font-size: 0.48em;
      font-weight: 700;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      white-space: nowrap;
    }

    p {
      margin: 0 0 8px;
      color: var(--muted);
      line-height: 1.38;
      font-size: 0.9rem;
    }

    .lead {
      max-width: 100ch;
      color: var(--ink);
      font-size: 0.98rem;
      margin-bottom: 0;
    }

    .layout-2 {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 14px;
      align-items: stretch;
      min-height: 0;
    }

    .layout-3 {
      display: grid;
      grid-template-columns: repeat(3, minmax(0, 1fr));
      gap: 12px;
      align-items: stretch;
      min-height: 0;
    }

    .panel > .layout-2,
    .panel > .layout-3,
    .panel > .card {
      margin-top: 0 !important;
    }

    .card {
      padding: 14px;
      border-radius: 18px;
      background: rgba(255, 255, 255, 0.72);
      border: 1px solid var(--line);
      min-height: 0;
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .card.soft {
      background: rgba(219, 236, 232, 0.45);
    }

    .code {
      font-family: Consolas, "Courier New", monospace;
      color: var(--accent-strong);
      font-size: 0.86rem;
    }

    .viz-shell {
      position: relative;
      padding: 12px;
      border-radius: 18px;
      background: rgba(255, 255, 255, 0.76);
      border: 1px solid var(--line);
      min-height: 0;
      display: flex;
      flex-direction: column;
    }

    .svg-frame {
      border-radius: 18px;
      overflow: hidden;
      border: 1px solid rgba(13, 106, 116, 0.12);
      background:
        linear-gradient(180deg, rgba(219, 236, 232, 0.5), rgba(255, 255, 255, 0.92));
      aspect-ratio: 1 / 1;
      width: 100%;
      min-height: 0;
    }

    .svg-stage {
      width: 100%;
      min-height: 0;
      flex: 1;
      display: flex;
      align-items: stretch;
      justify-content: stretch;
    }

    .svg-stage > svg {
      width: 100%;
      height: 100%;
    }

    .layout-2 > .card .svg-frame,
    .layout-2 > .viz-shell .svg-frame,
    .layout-2 > .column-stack .svg-frame {
      max-width: var(--viz-2col-size);
      margin: 0 auto;
    }

    .layout-3 .svg-frame {
      max-width: var(--viz-3col-size);
      margin: 0 auto;
    }

    .slide:nth-of-type(4) .layout-3,
    .slide:nth-of-type(5) .layout-3,
    .slide:nth-of-type(6) .layout-3,
    .slide:nth-of-type(7) .layout-3 {
      align-items: stretch;
    }

    .slide:nth-of-type(4) .card .svg-frame,
    .slide:nth-of-type(5) .card .svg-frame,
    .slide:nth-of-type(6) .card .svg-frame,
    .slide:nth-of-type(7) .card .svg-frame,
    .slide:nth-of-type(8) .card .svg-frame,
    .slide:nth-of-type(9) .card .svg-frame {
      max-width: none;
      width: 100%;
      flex: 1;
      margin: 0;
      border: 0;
      border-radius: 0;
      background: transparent;
    }

    .slide:nth-of-type(4) .card > .svg-frame,
    .slide:nth-of-type(5) .card > .svg-frame,
    .slide:nth-of-type(6) .card > .svg-frame,
    .slide:nth-of-type(7) .card > .svg-frame,
    .slide:nth-of-type(8) .card > .svg-frame,
    .slide:nth-of-type(9) .card > .svg-frame {
      min-height: 0;
    }

    .slide:nth-of-type(4) .card > .svg-frame > svg,
    .slide:nth-of-type(5) .card > .svg-frame > svg,
    .slide:nth-of-type(6) .card > .svg-frame > svg,
    .slide:nth-of-type(7) .card > .svg-frame > svg,
    .slide:nth-of-type(8) .card > .svg-frame > svg,
    .slide:nth-of-type(9) .card > .svg-frame > svg {
      width: 100%;
      height: 100%;
    }

    svg {
      display: block;
      width: 100%;
      height: auto;
    }

    .legend {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-top: 8px;
      color: var(--muted);
      font-size: 0.78rem;
    }

    .legend-bar {
      flex: 1;
      height: 14px;
      border-radius: 999px;
      border: 1px solid rgba(29, 43, 47, 0.1);
      background: linear-gradient(90deg, #2b6172, #f7f1e5, #c8753a);
    }

    .control-row {
      display: flex;
      gap: 8px;
      align-items: center;
      flex-wrap: wrap;
    }

    .seed-input {
      min-width: 180px;
      padding: 8px 10px;
      border-radius: 999px;
      border: 1px solid var(--line);
      background: rgba(255, 255, 255, 0.82);
      color: var(--ink);
      font: inherit;
    }

    button {
      border: 0;
      border-radius: 999px;
      background: var(--accent);
      color: white;
      padding: 9px 15px;
      font: inherit;
      cursor: pointer;
      transition: transform 120ms ease, background 120ms ease;
    }

    button:hover {
      transform: translateY(-1px);
      background: var(--accent-strong);
    }

    button.secondary {
      background: rgba(255, 255, 255, 0.78);
      color: var(--ink);
      border: 1px solid var(--line);
    }

    button.secondary.active {
      background: var(--soft);
      color: var(--accent-strong);
      border-color: rgba(13, 106, 116, 0.18);
    }

    .info-grid {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 10px;
      margin-top: 10px;
    }

    .metric {
      padding: 10px 12px;
      border-radius: 14px;
      background: rgba(247, 241, 229, 0.9);
      border: 1px solid rgba(29, 43, 47, 0.08);
    }

    .metric .label {
      color: var(--muted);
      font-size: 0.84rem;
      margin-bottom: 4px;
    }

    .metric .value {
      font-family: Consolas, "Courier New", monospace;
      font-size: 0.98rem;
      color: var(--ink);
    }

    .formula-box {
      min-height: 150px;
    }

    .slide2-breakdown-card {
      flex: 1;
      min-height: 0;
    }

    .slide2-breakdown-layout {
      display: grid;
      grid-template-columns: minmax(180px, 0.95fr) minmax(0, 1fr);
      gap: 14px;
      align-items: stretch;
      margin-top: 8px;
      flex: 1;
      min-height: 0;
    }

    .slide2-detail-frame {
      max-width: none !important;
      width: 100%;
      height: 100%;
      margin: 0 !important;
      align-self: stretch;
    }

    .slide2-detail-frame > svg {
      width: 100%;
      height: 100%;
    }

    .slide2-formula-box {
      min-height: 0;
      align-self: center;
    }

    .hover-tooltip {
      position: absolute;
      left: 0;
      top: 0;
      z-index: 4;
      width: min(340px, calc(100% - 24px));
      padding: 12px 14px;
      border-radius: 16px;
      background: rgba(255, 250, 240, 0.96);
      border: 1px solid rgba(29, 43, 47, 0.14);
      box-shadow: 0 14px 28px rgba(29, 43, 47, 0.14);
      pointer-events: none;
      opacity: 0;
      transform: translate(14px, 14px);
      transition: opacity 120ms ease;
    }

    .hover-tooltip.visible {
      opacity: 1;
    }

    .mini-curve {
      margin: 8px 0 10px;
      padding: 8px 10px;
      border-radius: 14px;
      background: rgba(219, 236, 232, 0.35);
      border: 1px solid rgba(13, 106, 116, 0.1);
    }

    .mini-curve svg {
      width: 100%;
      max-width: 240px;
    }

    .formula-line {
      margin: 6px 0;
      font-family: Consolas, "Courier New", monospace;
      color: var(--ink);
      font-size: 0.84rem;
      line-height: 1.4;
      word-break: break-word;
      white-space: pre-line;
    }

    .hover-note {
      margin-top: 6px;
      color: var(--muted);
      font-size: 0.8rem;
    }

    .mini-grid-wrap {
      display: grid;
      gap: 8px;
    }

    .mini-grid {
      display: grid;
      grid-template-columns: repeat(5, minmax(0, 1fr));
      gap: 6px;
    }

    .cell {
      min-height: 48px;
      padding: 4px;
      border-radius: 12px;
      border: 1px solid rgba(255, 255, 255, 0.35);
      display: grid;
      place-items: center;
      text-align: center;
      line-height: 1.08;
      font-family: Consolas, "Courier New", monospace;
      font-size: 0.74rem;
      box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.22);
    }

    .cell .tiny {
      display: block;
      margin-top: 2px;
      font-size: 0.65rem;
      opacity: 0.82;
    }

    .column-stack {
      display: grid;
      gap: 10px;
      min-height: 0;
    }

    .slide1-compare-card {
      padding: 12px;
    }

    .slide1-compare-grid {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 12px;
      min-height: 0;
      flex: 1;
    }

    .slide1-preview {
      min-width: 0;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .slide1-preview > svg {
      width: 100%;
      aspect-ratio: 1 / 1;
      min-height: 0;
      border-radius: 18px;
      border: 1px solid rgba(13, 106, 116, 0.12);
      background: linear-gradient(180deg, rgba(219, 236, 232, 0.5), rgba(255, 255, 255, 0.92));
      overflow: hidden;
    }

    .stacked-viz {
      display: grid;
      gap: 10px;
    }

    .caption {
      color: var(--muted);
      font-size: 0.8rem;
      margin-top: 8px;
    }

    #slide2-dot-shell {
      justify-content: flex-start;
      gap: 10px;
    }

    #slide2-dot-shell .svg-stage {
      flex: 1;
    }

    #slide2-dot-shell #interpolation-grid-svg {
      display: block;
      width: 100%;
      height: 100%;
      min-height: 0;
    }

    #slide3-sync-shell {
      align-items: stretch;
      grid-template-columns: repeat(4, minmax(0, 1fr));
    }

    #slide3-sync-shell .card {
      gap: 4px;
    }

    #slide3-sync-shell .svg-frame {
      max-width: none;
      width: 100%;
      flex: 1;
      margin: 0;
      border: 0;
      border-radius: 0;
      background: transparent;
    }

    #slide3-sync-shell .svg-frame > svg {
      width: 100%;
      height: 100%;
    }

    .slide3-inspector {
      justify-content: flex-start;
      background: rgba(255, 250, 240, 0.96);
      border: 1px solid rgba(29, 43, 47, 0.14);
      box-shadow: 0 14px 28px rgba(29, 43, 47, 0.08);
    }

    .slide3-inspector-copy {
      margin-bottom: 4px;
      font-size: 0.84rem;
    }

    .slide3-inspector-controls {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      margin-bottom: 6px;
    }

    .slide3-inspector-controls button {
      padding: 7px 12px;
    }

    .slide3-inspector .mini-curve {
      margin-top: 0;
    }

    #slide4-sync-shell {
      align-items: stretch;
      grid-template-columns: repeat(4, minmax(0, 1fr));
    }

    #slide4-sync-shell .card {
      gap: 4px;
    }

    #slide4-sync-shell .svg-frame {
      max-width: none;
      width: 100%;
      flex: 1;
      margin: 0;
      border: 0;
      border-radius: 0;
      background: transparent;
    }

    #slide4-sync-shell .svg-frame > svg {
      width: 100%;
      height: 100%;
    }

    .slide4-inspector {
      justify-content: flex-start;
      background: rgba(255, 250, 240, 0.96);
      border: 1px solid rgba(29, 43, 47, 0.14);
      box-shadow: 0 14px 28px rgba(29, 43, 47, 0.08);
    }

    .slide4-inspector .mini-curve {
      margin-top: 0;
    }

    #slide4-x1-svg,
    #slide4-x2-svg,
    #slide4-final-svg,
    #freq1-svg,
    #freq2-svg,
    #freq4-svg,
    #fbm3-svg,
    #fbm5-svg,
    #fbm6-svg,
    #decay-exp-svg,
    #decay-linear-svg,
    #decay-none-svg {
      max-height: 100%;
    }

    .nav {
      position: sticky;
      bottom: 0;
      z-index: 2;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 14px;
      padding: 10px 16px 14px;
    }

    .dots {
      display: flex;
      gap: 10px;
    }

    .dot {
      width: 11px;
      height: 11px;
      border-radius: 50%;
      background: rgba(29, 43, 47, 0.18);
    }

    .dot.active {
      background: var(--accent);
      transform: scale(1.24);
    }

    @media (max-width: 1080px) {
      .layout-2,
      .layout-3 {
        grid-template-columns: 1fr;
      }

      #slide3-sync-shell,
      #slide4-sync-shell {
        grid-template-columns: repeat(2, minmax(0, 1fr));
      }
    }

    @media (max-width: 760px) {
      body {
        overflow: auto;
      }

      .deck {
        height: auto;
        min-height: 100%;
      }

      .slides {
        min-height: auto;
      }

      .slide {
        height: auto;
        min-height: auto;
        padding: 18px;
        overflow: visible;
      }

      .panel {
        height: auto;
        padding: 20px;
        overflow: visible;
      }

      .panel > :last-child {
        flex: 0 0 auto;
      }

      .info-grid {
        grid-template-columns: 1fr;
      }

      .mini-grid {
        grid-template-columns: repeat(5, minmax(44px, 1fr));
      }

      .cell {
        min-height: 48px;
      }

      .slide2-breakdown-layout {
        grid-template-columns: 1fr;
      }

      .slide1-compare-grid {
        grid-template-columns: 1fr;
      }

      #slide3-sync-shell,
      #slide4-sync-shell {
        grid-template-columns: 1fr;
      }
    }