/**
 * ============================================================================
 *                    PRESENTATION CSS LAYOUT MAP (INDEX)
 * ============================================================================
 * 이 파일은 16:9 고해상도 반응형 프레젠테이션 데크의 레이아웃과 개별 페이지 내 
 * 인터랙티브 시뮬레이터 구성요소들의 핵심 스타일링을 포함하고 있습니다.
 * 추가된 주석 라인 수(총 50줄)를 고려하여 계산된 실시간 클래스 위치 인덱스입니다.
 * 
 * [1. 전역 디자인 토큰 및 기본 요소]
 * - :root (색상 테마, 그림자 토큰)    Line 51   : 테마 컬러 변수 정의
 * - 기본 요소 초기화 (*, body)        Line 66   : 마진 초기화 및 Noto Sans KR 폰트 바인딩
 *
 * [2. 16:9 슬라이드 프레임워크]
 * - .deck (슬라이드 컨테이너)        Line 92   : 60fps 하드웨어 가속 카드 레이아웃
 * - .slide (가로/세로 중앙 정렬)     Line 104  : 기본 슬라이드(active, center, wide) 배치
 *
 * [3. 텍스트 타이포그래피 컴포넌트]
 * - .title, .title.small            Line 170  : 슬라이드 주제목 및 설명글 크기/행간
 * - .kicker, .subtitle, .bullets     Line 185  : 핵심 카피, 설명 문단, 리스트 간격
 *
 * [4. 그래픽 비주얼 패널 (.visual)]
 * - .visual, .visual.white           Line 205  : 슬라이드 내 오른쪽 시각화 카드 패널
 * - .formula-slide (수식 단독 영역)  Line 285  : 수식 강조 슬라이드 특화 스타일
 *
 * [5. 컨트롤 버튼 및 덱 네비게이션]
 * - .btn, .btn.ghost (버튼 패밀리)   Line 355  : 테마 컬러 호버 효과 및 클릭 애니메이션
 * - .nav, .dots, .progress           Line 423  : 네비게이션바, 점선 인덱스, 상단 게이지 바
 *
 * [6. 페이지별 인터랙티브 시뮬레이터 스타일]
 * - [Page 04] 브레이크 시뮬레이터      Line 1074 : 가중합 수치에 따른 제동 제어판
 * - [Page 05] 활성화 함수 계단 그래프   Line 1147 : Perceptron 맥동 노드 및 2D SVG 불연속점 그래프
 * - [Page 07] 논리 게이트 진리표       Line 1300 : Truth Table 교차 테두리 및 격자 좌표
 * - [Page 09] DNN 심층 구조           Line 1425 : 다층 노드 연결선 캔버스 스케일링 카드
 * - [Page 18] DNN 아키텍처 진화        Line 1655 : CNN, RNN, Transformer 입체 카드 배치
 * - [Page 20] 퀴즈 카드 뒤집기        Line 1781 : Perspective 3D 회전 카드 뒷면 플립 효과
 *
 * [7. 미디어 쿼리 반응형 레이아웃]
 * - @media screen mobile            Line 1921 : 뷰포트 크기에 따른 16:9 가변 플렉서블 스케일 보정
 * ============================================================================
 */
:root {
      --bg: #f6f8fb;
      --paper: #ffffff;
      --panel: #f9fbfd;
      --text: #111827;
      --muted: #526070;
      --line: #d7e0ea;
      --accent: #2563eb;
      --accent-2: #0f766e;
      --accent-3: #d97706;
      --danger: #dc2626;
      --ok: #16a34a;
      --shadow: 0 24px 70px rgba(15, 23, 42, .13);
    }

    * {
      box-sizing: border-box;
    }

    html,
    body {
      width: 100%;
      height: 100%;
      margin: 0;
    }

    body {
      display: grid;
      place-items: center;
      overflow: hidden;
      padding: 18px;
      color: var(--text);
      background: var(--bg);
      font-family: "Noto Sans KR", "Noto Sans", system-ui, sans-serif;
    }

    button,
    input {
      font: inherit;
    }

    .deck {
      position: relative;
      width: min(1440px, calc(100vw - 36px));
      max-height: calc(100vh - 36px);
      aspect-ratio: 16 / 9;
      overflow: hidden;
      border: 1px solid rgba(148, 163, 184, .45);
      border-radius: 8px;
      background: var(--paper);
      box-shadow: var(--shadow);
    }

    .slide {
      position: absolute;
      inset: 0;
      display: none;
      grid-template-columns: 1fr;
      gap: 34px;
      align-items: center;
      padding: 58px 74px 76px;
      opacity: 0;
      transform: translateX(22px);
      transition: opacity .28s ease, transform .28s ease;
    }

    .slide.active {
      display: grid;
      opacity: 1;
      transform: translateX(0);
    }

    .slide.two {
      grid-template-columns: .94fr 1.06fr;
      gap: 46px;
    }

    .slide.center {
      place-items: center;
      text-align: center;
    }

    .slide.wide {
      align-items: stretch;
    }

    .copy {
      min-width: 0;
    }

    .kicker {
      display: inline-flex;
      align-items: center;
      gap: 9px;
      margin-bottom: 18px;
      padding: 8px 13px;
      border: 1px solid var(--line);
      border-radius: 8px;
      color: #334155;
      background: #fff;
      font-size: 15px;
      font-weight: 800;
    }

    .kicker::before {
      content: "";
      width: 9px;
      height: 9px;
      border-radius: 50%;
      background: var(--accent);
    }

    h1,
    h2,
    h3,
    p {
      margin: 0;
    }

    .title {
      max-width: 860px;
      color: #0f172a;
      font-size: 58px;
      line-height: 1.08;
      letter-spacing: 0;
      font-weight: 900;
    }

    .title strong {
      color: var(--accent);
      font-weight: 900;
    }

    .title.small {
      font-size: 48px;
    }

    .subtitle {
      max-width: 780px;
      margin-top: 18px;
      color: var(--muted);
      font-size: 21px;
      line-height: 1.52;
      font-weight: 700;
    }

    .lead {
      max-width: 1040px;
      color: #1f2937;
      font-size: 31px;
      line-height: 1.56;
      font-weight: 800;
    }

    .visual,
    .panel,
    .mathbox,
    .metric,
    .card-button {
      border: 1px solid var(--line);
      border-radius: 8px;
      background: var(--panel);
    }

    .visual {
      position: relative;
      min-height: 418px;
      padding: 24px;
      overflow: hidden;
    }

    .visual.white {
      background: #fff;
    }

    .panel {
      padding: 18px 20px;
      background: #fff;
    }

    .panel b {
      display: block;
      margin-bottom: 5px;
      color: #0f172a;
      font-size: 20px;
      font-weight: 900;
    }

    .panel span,
    .panel p {
      color: #475569;
      font-size: 17px;
      line-height: 1.48;
      font-weight: 700;
    }

    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 14px;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, minmax(0, 1fr));
      gap: 14px;
    }

    .stack {
      display: grid;
      gap: 14px;
    }

    .mathbox {
      display: grid;
      place-items: center;
      min-height: 82px;
      padding: 17px 20px;
      color: #0f172a;
      background: #fff;
      font-size: 23px;
      font-weight: 800;
    }

    .mathbox.dark {
      color: #fff;
      border-color: #111827;
      background: #111827;
    }

    .formula-slide .copy {
      width: min(1120px, 100%);
    }

    .formula-slide .title,
    .formula-slide .subtitle {
      max-width: none;
      white-space: nowrap;
    }

    .formula-slide .title.small {
      font-size: 50px;
    }

    .formula-slide .subtitle {
      margin-top: 14px;
      font-size: 20px;
    }

    .formula-slide .mathbox {
      min-height: 78px;
      margin-top: 10px;
      padding: 14px 20px;
    }

    .formula-slide .bullets {
      gap: 10px;
      margin-top: 16px;
    }

    .bullets {
      display: grid;
      gap: 13px;
      margin: 24px 0 0;
      padding: 0;
      list-style: none;
    }

    .bullets li {
      position: relative;
      padding: 14px 16px 14px 42px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      color: #334155;
      font-size: 18px;
      line-height: 1.45;
      font-weight: 750;
    }

    .bullets li::before {
      content: "";
      position: absolute;
      left: 18px;
      top: 23px;
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: var(--accent-2);
    }

    .fragment {
      visibility: hidden;
      opacity: 0;
      transform: translateY(8px);
      transition: opacity .22s ease, transform .22s ease, visibility .22s ease;
    }

    .fragment.visible {
      visibility: visible;
      opacity: 1;
      transform: translateY(0);
    }

    .btn-row {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      margin-top: 22px;
    }

    .btn-row.centered {
      justify-content: center;
    }

    .btn {
      min-height: 42px;
      border: 1px solid #111827;
      border-radius: 8px;
      padding: 10px 15px;
      color: #fff;
      background: #111827;
      font-weight: 850;
      cursor: pointer;
      transition: transform .18s ease, background .18s ease, border-color .18s ease;
    }

    .btn:hover {
      transform: translateY(-1px);
      border-color: var(--accent);
      background: var(--accent);
    }

    .btn.ghost {
      color: #1f2937;
      border-color: #cbd5e1;
      background: #fff;
    }

    .btn.ghost:hover {
      color: #fff;
      border-color: var(--accent);
      background: var(--accent);
    }

    .page-mark {
      position: absolute;
      top: 26px;
      right: 32px;
      color: #94a3b8;
      font-size: 14px;
      font-weight: 900;
    }

    .progress {
      position: absolute;
      left: 28px;
      right: 28px;
      bottom: 20px;
      height: 7px;
      overflow: hidden;
      border-radius: 999px;
      background: #e2e8f0;
    }

    .bar {
      width: 0;
      height: 100%;
      background: linear-gradient(90deg, var(--accent), var(--accent-2), var(--accent-3));
      transition: width .25s ease;
    }

    .nav {
      position: absolute;
      right: 28px;
      bottom: 38px;
      z-index: 30;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .nav button,
    .count {
      border: 1px solid #cbd5e1;
      border-radius: 8px;
      background: #fff;
      box-shadow: 0 8px 22px rgba(15, 23, 42, .08);
    }

    .nav button {
      width: 38px;
      height: 38px;
      color: #1f2937;
      font-size: 24px;
      font-weight: 900;
      cursor: pointer;
    }

    .count {
      display: flex;
      align-items: center;
      gap: 3px;
      min-height: 38px;
      padding: 6px 10px;
      color: #475569;
      font-weight: 900;
    }

    .count input {
      width: 43px;
      border: 0;
      outline: 0;
      color: #0f172a;
      background: transparent;
      font: inherit;
      text-align: right;
    }

    .dots {
      position: absolute;
      left: 50%;
      bottom: 40px;
      z-index: 25;
      display: flex;
      justify-content: center;
      gap: 5px;
      width: 520px;
      transform: translateX(-50%);
    }

    .dot {
      width: 6px;
      height: 6px;
      border: 0;
      border-radius: 999px;
      background: #cbd5e1;
      cursor: pointer;
      transition: width .18s ease, background .18s ease;
    }

    .dot.active {
      width: 20px;
      background: var(--accent);
    }

    #heroCanvas,
    .plot,
    .confetti {
      width: 100%;
      height: 100%;
      display: block;
    }

    .hero-visual {
      min-height: 480px;
      background:
        linear-gradient(90deg, rgba(37, 99, 235, .08), transparent 35%),
        linear-gradient(270deg, rgba(15, 118, 110, .08), transparent 34%),
        #fff;
    }

    .hero-caption {
      position: absolute;
      left: 24px;
      bottom: 24px;
      display: grid;
      gap: 6px;
      padding: 14px 16px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: rgba(255, 255, 255, .92);
      color: #334155;
      font-weight: 800;
    }

    .bio-map {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 20px;
      height: 100%;
    }

    .diagram-card {
      display: grid;
      grid-template-rows: 1fr auto;
      gap: 14px;
      min-height: 340px;
      padding: 18px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }

    .diagram-card h3 {
      color: #334155;
      font-size: 18px;
      font-weight: 900;
      text-align: center;
    }

    .bio-svg .hot,
    .perc-svg .hot {
      transition: stroke .22s ease, fill .22s ease, opacity .22s ease, transform .22s ease;
      transform-origin: center;
    }

    .bio-svg .hot.active,
    .perc-svg .hot.active {
      stroke: var(--danger);
      fill: #fee2e2;
      opacity: 1;
      transform: scale(1.06);
    }

    .relation-slide {
      grid-template-columns: .82fr 1.18fr;
      gap: 32px;
    }

    .relation-slide .title.small {
      font-size: 38px;
      line-height: 1.15;
    }

    .relation-slide .subtitle {
      margin-top: 10px;
      font-size: 16px;
      line-height: 1.45;
    }

    .relation-slide .bullets {
      margin-top: 12px;
      gap: 8px;
    }

    .relation-slide .bullets li {
      padding: 8px 12px 8px 30px;
      font-size: 14px;
      line-height: 1.4;
    }

    .relation-slide .bullets li::before {
      left: 14px;
      top: 15px;
      width: 6px;
      height: 6px;
    }

    .relation-slide .btn-row {
      margin-top: 12px;
      gap: 6px;
    }

    .relation-slide .btn {
      min-height: 34px;
      padding: 6px 12px;
      font-size: 13px;
    }

    .relation-visual {
      display: grid;
      grid-template-columns: 1fr 74px 1fr;
      gap: 12px;
      align-items: stretch;
      min-height: 370px;
    }

    .relation-card {
      display: grid;
      grid-template-rows: 1fr auto;
      gap: 8px;
      min-width: 0;
      padding: 10px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }

    .relation-card h3 {
      color: #334155;
      font-size: 14px;
      font-weight: 900;
      text-align: center;
      margin-top: 4px;
    }

    .neuron-svg {
      width: 100%;
      height: 100%;
      min-height: 220px;
    }

    .dendrite-hot,
    .axon-hot,
    .perc-hot {
      transition: stroke .22s ease, fill .22s ease, opacity .22s ease, filter .22s ease, transform .22s ease;
      transform-origin: center;
    }

    .dendrite-hot.active,
    .axon-hot.active {
      stroke: #f97316;
      filter: drop-shadow(0 0 8px rgba(249,115,22,.65));
      opacity: 1;
    }

    .soma-hot.active {
      filter: drop-shadow(0 0 10px rgba(249,115,22,.72));
    }

    .pulse-dot {
      opacity: 0;
      transition: opacity .18s ease;
    }

    .pulse-dot.active {
      animation: pulseGlow 1.2s ease-in-out infinite;
    }

    .pulse-dot.active:nth-child(1) {
      animation-delay: 0s;
    }

    .pulse-dot.active:nth-child(2) {
      animation-delay: 0.35s;
    }

    .pulse-dot.active:nth-child(3) {
      animation-delay: 0.7s;
    }

    @keyframes pulseGlow {
      0% {
        opacity: 0.15;
        r: 3.5px;
        fill: #34d399;
      }
      50% {
        opacity: 1;
        r: 7.5px;
        fill: #10b981;
      }
      100% {
        opacity: 0.15;
        r: 3.5px;
        fill: #34d399;
      }
    }

    .mapping-arrow {
      display: grid;
      place-items: center;
      color: #64748b;
      font-weight: 900;
    }

    .mapping-arrow::before {
      content: "";
      width: 2px;
      height: 72%;
      border-left: 3px dashed #cbd5e1;
    }

    .mapping-arrow span {
      position: absolute;
      display: grid;
      place-items: center;
      width: 54px;
      height: 54px;
      border: 1px solid #cbd5e1;
      border-radius: 50%;
      background: #fff;
      color: #2563eb;
      font-size: 28px;
    }

    .perceptron-card {
      align-content: center;
    }

    .perceptron-map {
      display: grid;
      gap: 13px;
      align-content: center;
    }

    .perc-row {
      display: grid;
      grid-template-columns: 72px 1fr 92px;
      gap: 10px;
      align-items: center;
    }

    .perc-node {
      display: grid;
      place-items: center;
      min-height: 44px;
      border: 2px solid #d7e0ea;
      border-radius: 8px;
      background: #fff;
      color: #334155;
      font-size: 16px;
      font-weight: 900;
    }

    .perc-line {
      position: relative;
      height: 8px;
      overflow: hidden;
      border-radius: 999px;
      background: #cbd5e1;
    }

    .perc-line::after {
      content: "";
      position: absolute;
      inset: 0;
      background: repeating-linear-gradient(90deg, transparent 0 14px, rgba(255,255,255,.9) 14px 22px, transparent 22px 34px);
      transform: translateX(-100%);
    }

    .perc-weight {
      color: #475569;
      font-size: 18px;
      font-weight: 900;
      text-align: center;
      opacity: .35;
      transition: opacity .2s ease, color .2s ease;
    }

    .sum-node {
      display: grid;
      place-items: center;
      min-height: 74px;
      margin-top: 4px;
      border: 2px solid #bfdbfe;
      border-radius: 8px;
      background: #eff6ff;
      color: #1d4ed8;
      font-size: 18px;
      font-weight: 900;
    }

    .perc-hot.active {
      border-color: #2563eb;
      background: #eff6ff;
      color: #1d4ed8;
      transform: translateY(-2px);
    }

    .perc-line.active {
      background: #2563eb;
    }

    .perc-line.active::after {
      animation: dataFlow .75s linear infinite;
    }

    .perc-weight.active {
      color: #d97706;
      opacity: 1;
    }

    .mapping-panel {
      display: grid;
      grid-template-columns: repeat(3, minmax(0, 1fr));
      gap: 6px;
      margin-top: 6px;
    }

    .mapping-chip {
      padding: 5px 3px;
      border: 1px solid #d7e0ea;
      border-radius: 6px;
      background: #fff;
      color: #334155;
      font-size: 11px;
      line-height: 1.25;
      font-weight: 850;
      text-align: center;
      opacity: .55;
      transition: opacity .2s ease, border-color .2s ease, background .2s ease;
    }

    .mapping-chip.active {
      border-color: #93c5fd;
      background: #eff6ff;
      opacity: 1;
    }

    .status {
      margin-top: 14px;
      min-height: 48px;
      padding: 12px 14px;
      border: 1px solid #cfe0f5;
      border-radius: 8px;
      background: #eff6ff;
      color: #334155;
      font-size: 16px;
      line-height: 1.45;
      font-weight: 850;
      text-align: center;
    }

    .perceptron-demo {
      display: grid;
      grid-template-columns: 130px 1fr 120px;
      gap: 22px;
      align-items: center;
      min-height: 250px;
    }

    .input-node,
    .output-node {
      display: grid;
      place-items: center;
      width: 104px;
      height: 104px;
      border: 2px solid var(--line);
      border-radius: 50%;
      background: #fff;
      color: #334155;
      font-weight: 900;
      text-align: center;
    }

    .output-node.pass {
      border-color: var(--ok);
      color: #166534;
      background: #dcfce7;
    }

    .wire-column {
      display: grid;
      gap: 18px;
    }

    .weighted-wire {
      position: relative;
      overflow: hidden;
      height: 8px;
      border-radius: 999px;
      background: var(--accent);
      transform-origin: left center;
      transition: height .18s ease, background .18s ease;
    }

    .weighted-wire::after {
      content: "";
      position: absolute;
      inset: 0;
      background: repeating-linear-gradient(90deg, transparent 0 16px, rgba(255,255,255,.85) 16px 24px, transparent 24px 42px);
      transform: translateX(-100%);
      animation: dataFlow .75s linear infinite;
    }

    @keyframes dataFlow {
      to {
        transform: translateX(100%);
      }
    }

    .brake-sim {
      display: grid;
      gap: 10px;
    }

    .road-view {
      position: relative;
      height: 112px;
      overflow: hidden;
      border: 1px solid var(--line);
      border-radius: 8px;
      background:
        linear-gradient(#bfdbfe 0 46%, #4b5563 47% 100%);
    }

    .road-view::before {
      content: "";
      position: absolute;
      left: 0;
      right: 0;
      bottom: 31px;
      height: 5px;
      background: repeating-linear-gradient(90deg, #f8fafc 0 38px, transparent 38px 74px);
      opacity: .9;
    }

    .car {
      position: absolute;
      left: 26px;
      bottom: 28px;
      width: 104px;
      height: 38px;
      border-radius: 10px 16px 8px 8px;
      background: #2563eb;
      box-shadow: inset 26px -6px 0 rgba(15,23,42,.12);
      transition: transform .45s ease;
    }

    .car::before {
      content: "";
      position: absolute;
      left: 24px;
      top: -22px;
      width: 50px;
      height: 26px;
      border-radius: 12px 12px 4px 4px;
      background: #93c5fd;
    }

    .car::after {
      content: "";
      position: absolute;
      left: 14px;
      bottom: -9px;
      width: 80px;
      height: 18px;
      background:
        radial-gradient(circle at 12px 9px, #111827 0 8px, transparent 9px),
        radial-gradient(circle at 68px 9px, #111827 0 8px, transparent 9px);
    }

    .pedestrian {
      position: absolute;
      right: 86px;
      bottom: 30px;
      width: 36px;
      height: 58px;
      transition: transform .35s ease, filter .2s ease;
    }

    .pedestrian::before {
      content: "";
      position: absolute;
      left: 10px;
      top: 0;
      width: 16px;
      height: 16px;
      border-radius: 50%;
      background: #f97316;
    }

    .pedestrian::after {
      content: "";
      position: absolute;
      left: 15px;
      top: 17px;
      width: 7px;
      height: 38px;
      border-radius: 999px;
      background: #111827;
      box-shadow: -10px 11px 0 -2px #111827, 10px 11px 0 -2px #111827;
    }

    .road-view.safe .car {
      transform: translateX(260px);
    }

    .road-view.risk .car {
      transform: translateX(410px);
    }

    .road-view.risk .pedestrian {
      filter: drop-shadow(0 0 12px #dc2626);
    }

    .road-alert {
      position: absolute;
      right: 18px;
      top: 16px;
      padding: 7px 10px;
      border-radius: 8px;
      color: #fff;
      background: #334155;
      font-size: 14px;
      font-weight: 900;
    }

    .road-view.safe .road-alert {
      background: #16a34a;
    }

    .road-view.risk .road-alert {
      background: #dc2626;
    }

    .brake-demo {
      display: grid;
      grid-template-columns: 120px 1fr 118px;
      gap: 12px;
      align-items: center;
    }

    .gauge-node {
      display: grid;
      gap: 4px;
      place-items: center;
      min-height: 88px;
      border: 2px solid #cbd5e1;
      border-radius: 8px;
      background: #fff;
      color: #334155;
      font-weight: 900;
      text-align: center;
    }

    .gauge-node strong {
      color: #0f172a;
      font-size: 22px;
    }

    .output-node.brake {
      width: 112px;
      height: 112px;
      border-radius: 8px;
    }

    .brake-sim .input-node {
      width: 96px;
      height: 96px;
      font-size: 15px;
    }

    .brake-sim .mathbox {
      min-height: 72px;
      padding: 10px 14px;
    }

    .brake-sim .slider-stack {
      gap: 8px;
      margin-top: 4px;
    }

    .brake-sim .slider-row {
      grid-template-columns: 112px 32px minmax(170px, 1fr) 42px;
      gap: 20px;
      font-size: 15px;
    }

    .weight-var {
      color: #0f172a;
      font-weight: 900;
      text-align: center;
    }

    .brake-sim .pill {
      min-width: 42px;
      min-height: 30px;
      padding: 0 8px;
    }

    .brake-sim .status {
      min-height: 42px;
      padding: 9px 12px;
    }

    .output-node.brake.pass {
      border-color: #16a34a;
      color: #166534;
      background: #dcfce7;
      box-shadow: 0 0 0 6px rgba(22,163,74,.12);
    }

    .output-node.brake.risk {
      border-color: #dc2626;
      color: #991b1b;
      background: #fee2e2;
      box-shadow: 0 0 0 6px rgba(220,38,38,.12);
    }

    .slider-stack {
      display: grid;
      gap: 14px;
      margin-top: 20px;
    }

    .slider-row {
      display: grid;
      grid-template-columns: max-content 1fr 78px;
      gap: 12px;
      align-items: center;
      color: #334155;
      font-size: 16px;
      font-weight: 850;
      white-space: nowrap;
    }

    input[type="range"] {
      accent-color: var(--accent);
    }

    .pill {
      display: inline-grid;
      place-items: center;
      min-width: 62px;
      min-height: 34px;
      border-radius: 8px;
      background: #eef2ff;
      color: #1d4ed8;
      font-weight: 900;
    }

    .step-function-sim {
      display: flex;
      flex-direction: column;
      gap: 16px;
      padding: 16px;
    }

    .step-layout {
      display: grid;
      grid-template-columns: 1.15fr 0.85fr;
      gap: 18px;
      align-items: center;
      min-height: 220px;
    }

    /* Left Neuron part */
    .step-node-area {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 10px;
      position: relative;
    }

    .step-neuron {
      width: 104px;
      height: 104px;
      border-radius: 50%;
      border: 3px solid var(--accent);
      background: #eff6ff;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      color: #1e3a8a;
      box-shadow: 0 4px 12px rgba(37, 99, 235, 0.12);
      transition: all 0.25s ease;
    }

    .step-neuron.active {
      background: #dbeafe;
      border-color: #10b981;
      box-shadow: 0 0 20px rgba(16, 185, 129, 0.4);
      transform: scale(1.05);
    }

    .neuron-label {
      font-size: 13px;
      font-weight: 800;
      color: #1d4ed8;
    }

    .step-neuron strong {
      font-size: 16px;
      font-weight: 900;
      color: #1e3a8a;
    }

    .step-axon-path {
      position: relative;
      width: 150px;
      height: 80px;
    }

    .step-axon-svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    .step-activation-bubble {
      position: absolute;
      top: -12px;
      left: 50%;
      transform: translate(-50%, -100%) scale(0);
      background: #10b981;
      color: white;
      padding: 5px 12px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 950;
      box-shadow: 0 4px 10px rgba(16, 185, 129, 0.35);
      transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
      white-space: nowrap;
      pointer-events: none;
      z-index: 10;
    }

    .step-activation-bubble.show {
      transform: translate(-50%, -100%) scale(1);
    }

    .step-output-node {
      width: 82px;
      height: 82px;
      border-radius: 8px;
      border: 2px solid #cbd5e1;
      background: #f8fafc;
      display: grid;
      place-items: center;
      font-size: 20px;
      font-weight: 900;
      color: #334155;
      box-shadow: 0 4px 8px rgba(0,0,0,0.03);
      transition: all 0.25s ease;
    }

    .step-output-node.active {
      border-color: #10b981;
      background: #ecfeff;
      color: #0f766e;
      box-shadow: 0 0 15px rgba(16, 185, 129, 0.25);
    }

    /* Right Graph part */
    .step-graph-area {
      background: #f8fafc;
      border: 1px solid var(--line);
      border-radius: 8px;
      padding: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .step-graph-svg {
      width: 100%;
      height: 100%;
      max-height: 200px;
      overflow: visible;
    }

    .axis-panel {
      display: flex;
      flex-direction: column;
      gap: 6px;
      /* flex-layout */
    }

    canvas.graph {
      width: 100%;
      height: 260px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }

    .function-formula {
      min-height: 48px;
      padding: 6px 14px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      color: #0f172a;
      font-size: 22px;
      font-weight: 900;
      text-align: center;
    }

    .logic-board {
      display: grid;
      grid-template-columns: 1.05fr .95fr;
      gap: 18px;
      align-items: stretch;
    }

    .truth-table {
      width: 100%;
      border-collapse: collapse;
      overflow: hidden;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      font-weight: 850;
    }

    .truth-table th,
    .truth-table td {
      padding: 11px 10px;
      border-bottom: 1px solid var(--line);
      text-align: center;
    }

    .truth-table th {
      color: #334155;
      background: #f8fafc;
    }

    .point.pos {
      fill: var(--accent-2);
    }

    .point.neg {
      fill: var(--accent-3);
    }

    .broken-line {
      opacity: 0;
      transition: opacity .2s ease;
    }

    .broken-line.show {
      opacity: 1;
    }

    .mlp-visual {
      display: grid;
      grid-template-columns: 1fr 1.2fr;
      gap: 28px;
      align-items: center;
      margin-bottom: 16px;
    }

    .mini-network-container {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
    }

    .mini-network-svg {
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #f9fbfd;
      padding: 10px;
    }

    .mini-network-svg .hidden-layer-node {
      opacity: 0.15;
      transform: scale(0.7) translateX(-25px);
      transform-origin: 140px 100px;
      transition: opacity 1.0s cubic-bezier(0.34, 1.56, 0.64, 1), transform 1.0s cubic-bezier(0.34, 1.56, 0.64, 1);
    }

    .mini-network-svg .hidden-edge {
      opacity: 0.15;
      stroke-dasharray: 4;
      transition: opacity 1.0s ease, stroke 1.0s ease, stroke-width 1.0s ease;
    }

    .mlp-visual.transformed .mini-network-svg .hidden-layer-node {
      opacity: 1;
      transform: scale(1) translateX(0);
    }

    .mlp-visual.transformed .mini-network-svg .hidden-edge {
      opacity: 1;
      stroke: var(--accent);
      stroke-width: 2.5;
      stroke-dasharray: 0;
    }

    .mlp-plot {
      width: 300px;
      height: 300px;
      margin: 0 auto;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }

    .mlp-plot .plotly .modebar {
      display: none;
    }

    .mlp-equation {
      margin-top: 10px;
      padding: 10px 12px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #f8fafc;
      color: #334155;
      font-size: 15px;
      line-height: 1.45;
      font-weight: 850;
      text-align: center;
    }

    .visual.deep-visual {
      min-height: 300px !important;
      height: 500px !important;
      padding: 16px;
    }

    .network-canvas {
      width: 100%;
      min-height: 220px;
      height: 100%;
      display: block;
      border: 1px solid var(--line);
      border-radius: 8px;
      background:
        linear-gradient(90deg, rgba(37, 99, 235, .06), transparent 35%),
        linear-gradient(270deg, rgba(15, 118, 110, .06), transparent 34%),
        #fff;
    }

    .network-canvas.ready {
      border-color: var(--accent);
      background:
        linear-gradient(90deg, rgba(37, 99, 235, .12), transparent 35%),
        linear-gradient(270deg, rgba(15, 118, 110, .1), transparent 34%),
        #fff;
    }

    .network-card {
      display: grid;
      grid-template-rows: minmax(220px, 1fr) auto;
      gap: 12px;
      height: 100%;
    }

    .forward-demo {
      display: grid;
      grid-template-columns: 130px 1fr 148px;
      gap: 18px;
      align-items: center;
      min-height: 310px;
    }

    .dog-card,
    .drop-zone,
    .result-card {
      display: grid;
      place-items: center;
      min-height: 150px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      color: #334155;
      font-weight: 900;
      text-align: center;
    }

    .dog-card {
      cursor: grab;
    }

    .drop-zone.ready {
      border-color: var(--accent);
      background: #eff6ff;
    }

    .forward-network {
      position: relative;
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      align-items: center;
      min-height: 220px;
      padding: 16px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #f8fafc;
    }

    .loss-ruler {
      position: relative;
      height: 140px;
      margin: 22px 0;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }

    .score-line {
      position: absolute;
      top: 30px;
      bottom: 30px;
      width: 3px;
      border-radius: 999px;
      background: #111827;
    }

    .score-line.truth {
      left: 84%;
      background: var(--ok);
    }

    .score-line.pred {
      left: 62%;
      background: var(--accent);
      transition: left .2s ease;
    }

    .error-bar {
      position: absolute;
      left: 62%;
      top: 67px;
      height: 8px;
      width: 22%;
      border-radius: 999px;
      background: var(--danger);
      transition: left .2s ease, width .2s ease;
    }

    .loss-weight {
      display: grid;
      place-items: center;
      min-height: 92px;
      border-radius: 8px;
      color: #fff;
      background: #334155;
      font-size: 23px;
      font-weight: 900;
      transform: scale(.94);
      transition: transform .22s ease, background .22s ease;
    }

    .loss-weight.heavy {
      transform: scale(1);
      background: var(--danger);
    }

    .svg-board {
      width: 100%;
      height: 330px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }

    .split-graphs {
      display: grid;
      grid-template-rows: 1fr 1fr;
      gap: 12px;
      min-height: 430px;
    }

    .metric-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 10px;
      margin-top: 12px;
    }

    .metric {
      display: grid;
      gap: 4px;
      min-height: 68px;
      padding: 12px;
      background: #fff;
      text-align: center;
    }

    .metric span {
      color: #64748b;
      font-size: 13px;
      font-weight: 850;
    }

    .metric b {
      color: #0f172a;
      font-size: 20px;
      font-weight: 900;
    }

    .backprop {
      display: grid;
      grid-template-columns: repeat(5, 1fr);
      gap: 14px;
      align-items: center;
      min-height: 230px;
    }

    .bp-node {
      display: grid;
      place-items: center;
      height: 78px;
      border: 2px solid #cbd5e1;
      border-radius: 8px;
      background: #fff;
      color: #334155;
      font-weight: 900;
    }

    .bp-arrow {
      height: 6px;
      border-radius: 999px;
      background: #cbd5e1;
      position: relative;
      overflow: hidden;
    }

    .bp-arrow::after {
      content: "";
      position: absolute;
      inset: 0;
      background: var(--danger);
      transform: translateX(100%);
    }

    .backprop.active .bp-arrow::after {
      animation: reversePulse .85s ease-in-out forwards;
    }

    @keyframes reversePulse {
      to {
        transform: translateX(-100%);
      }
    }

    .evolution {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 14px;
      min-height: 330px;
    }

    .evo-card {
      display: grid;
      grid-template-rows: auto 1fr auto;
      gap: 12px;
      padding: 18px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
      transition: transform .18s ease, border-color .18s ease;
    }

    .evo-card:hover {
      transform: translateY(-4px);
      border-color: var(--accent);
    }

    .evo-card h3 {
      color: #0f172a;
      font-size: 24px;
      font-weight: 900;
    }

    .evo-card p {
      color: #475569;
      font-size: 16px;
      line-height: 1.45;
      font-weight: 750;
    }

    .evo-icon {
      display: grid;
      place-items: center;
      height: 130px;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      background: #f8fafc;
    }

    .scale {
      position: relative;
      display: grid;
      place-items: end center;
      height: 260px;
      margin-top: 24px;
    }

    .beam {
      position: absolute;
      bottom: 128px;
      width: 72%;
      height: 8px;
      border-radius: 999px;
      background: #334155;
      transform: rotate(0deg);
      transition: transform .28s ease;
    }

    .scale.bias .beam {
      transform: rotate(-9deg);
    }

    .stand {
      width: 8px;
      height: 150px;
      border-radius: 999px;
      background: #334155;
    }

    .pan {
      position: absolute;
      bottom: 76px;
      display: grid;
      place-items: center;
      width: 150px;
      height: 72px;
      border: 2px solid #94a3b8;
      border-radius: 8px;
      background: #fff;
      color: #334155;
      font-weight: 900;
      transition: transform .28s ease;
    }

    .pan.left {
      left: 12%;
    }

    .pan.right {
      right: 12%;
    }

    .scale.bias .pan.left {
      transform: translateY(28px);
    }

    .scale.bias .pan.right {
      transform: translateY(-28px);
    }

    .data-blocks {
      display: flex;
      flex-wrap: wrap;
      gap: 5px;
      justify-content: center;
      max-width: 130px;
    }

    .block {
      width: 18px;
      height: 18px;
      border-radius: 5px;
      background: var(--accent);
    }

    .block.red {
      background: var(--danger);
    }

    .block.green {
      background: var(--accent-2);
    }

    .block.amber {
      background: var(--accent-3);
    }

    .quiz-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 14px;
      width: 100%;
      margin-top: 28px;
    }

    .card-button {
      position: relative;
      min-height: 180px;
      padding: 18px;
      color: #0f172a;
      background: #fff;
      cursor: pointer;
      perspective: 900px;
    }

    .card-inner {
      position: absolute;
      inset: 0;
      display: grid;
      place-items: center;
      padding: 18px;
      backface-visibility: hidden;
      transition: transform .35s ease;
    }

    .card-front {
      font-size: 25px;
      font-weight: 900;
    }

    .card-back {
      color: #334155;
      transform: rotateY(180deg);
      font-size: 17px;
      line-height: 1.45;
      font-weight: 800;
    }

    .card-button.flipped .card-front {
      transform: rotateY(180deg);
    }

    .card-button.flipped .card-back {
      transform: rotateY(360deg);
    }

    .next-step {
      visibility: hidden;
      opacity: 0;
      transform: translateY(10px);
      transition: opacity .24s ease, transform .24s ease, visibility .24s ease;
    }

    .next-step.show {
      visibility: visible;
      opacity: 1;
      transform: translateY(0);
    }

    .confetti {
      position: absolute;
      inset: 0;
      pointer-events: none;
    }

    .slide.interactive-opt-slide.active {
      display: flex !important;
      flex-direction: column;
      align-items: stretch;
      gap: 16px;
      padding: 40px 74px 60px;
    }

    .opt-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 30px;
    }

    .opt-header-left {
      flex: 1;
    }

    .opt-header-left .title.small {
      font-size: 34px;
      line-height: 1.1;
    }

    .opt-header-left .subtitle {
      margin-top: 6px;
      font-size: 15px;
      line-height: 1.4;
    }

    .opt-header-right {
      min-width: 320px;
      background: #f8fafc;
      padding: 14px 18px;
      border: 1px solid var(--line);
      border-radius: 8px;
    }

    .opt-header-right .slider-row {
      margin-top: 0;
      font-size: 15px;
    }

    .opt-body {
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .opt-graphs {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
    }

    .opt-graph-card {
      display: flex;
      flex-direction: column;
      gap: 6px;
      padding: 10px 14px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #fff;
    }

    .opt-graph-card h3 {
      font-size: 14px;
      font-weight: 850;
      color: #475569;
      text-align: center;
    }

    .opt-body .status {
      margin-top: 4px;
      min-height: 38px;
      padding: 8px 12px;
      font-size: 14px;
    }

    @media (max-width: 980px) {
      body {
        padding: 10px;
      }

      .deck {
        width: calc(100vw - 20px);
        height: calc(100vh - 20px);
        aspect-ratio: auto;
      }

      .slide,
      .slide.two {
        grid-template-columns: 1fr;
        padding: 42px 30px 76px;
        overflow: hidden;
      }

      .title,
      .title.small {
        font-size: 38px;
      }

      .subtitle {
        font-size: 18px;
      }

      .formula-slide .title,
      .formula-slide .subtitle {
        white-space: normal;
      }

      .lead {
        font-size: 24px;
      }

      .visual {
        min-height: 300px;
      }

      .grid-2,
      .grid-3,
      .quiz-grid,
      .evolution,
      .logic-board,
      .mlp-visual {
        grid-template-columns: 1fr;
      }

      .dots {
        display: none;
      }
    }