body {
    min-height: 100vh;
    margin: 0;
    flex-direction: column;
    justify-content: center;
    display: flex;
    /* 기존 space-between 제거 */
    align-items: center;
    font-family: 'Noto Sans KR', sans-serif;
    background-color: #f0f0f0;
    color: #0F172A;
    text-align: center;
  }

  body.game-active {
    justify-content: flex-start;
    align-items: flex-start;
  }

html, body {
  overflow-y: auto;
  /* allow horizontal scrolling when content exceeds viewport width */
  overflow-x: auto;
}
  #controls, #blockPanel {
    margin: 15px;
  }


  #blockPanel {
    width: 100px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
  }

  #gameScreen {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    margin: 0;
    /* 혹시 기본 마진 있으면 제거 */
    overflow-x: auto;
    width: 100%;
  }

  #gameLayout {
    flex: 1;
    /* 상단 h1과 하단 메뉴바 사이를 쭉 채움 */
    display: flex;
    justify-content: center;
    /* 좌우 중앙 */
    align-items: center;
    /* 상하 중앙 */
    gap: 2rem;
    margin: 0 auto;
    /* inline style로 준 margin-top 제거 */
    padding-bottom: 60px;
    /* 메뉴바 높이에 맞춰 조정 */
    box-sizing: border-box;
    width: max-content;
  }

  #mainScreen {
    padding: 50px;
  }

  .rightPanel {
    max-width: 600px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    flex-shrink: 0;
  }

  #problem-screen .rightPanel {
    overflow-x: auto;
  }

  #problem-screen #testcaseContainer {
    max-width: 90vw;
    max-height: 60vh;
    overflow: auto;
  }

  #problem-screen #testcaseTable {
    width: max-content;
  }

  #mainScreen button {
    margin: 10px;
    padding: 12px 20px;
    font-size: 1.2rem;
  }

  /* 모듈 기능 보류에 따라 메인화면의 모듈 관리 버튼 숨김 */
  #manageModulesBtn {
    display: none;
  }

  #guestbookArea button {
    margin: 10px;
    padding: 12px 20px;
    font-size: 1.2rem;
  }


  #guestbookList {
    max-height: 200px;
    /* 원하는 최대 높이로 조정 */
    overflow-y: auto;
    /* y축 스크롤 허용 */
    padding-right: 0.5rem;
    /* 스크롤바와 내용이 붙지 않도록 여유 */
  }

  #menuBar {
    width: 100%;
    background-color: #ddd;
    padding: 10px;
    text-align: center;
    position: fixed;
    bottom: 0;
    left: 0;
  }

  #menuBar button {
    margin: 0 5px;
    padding: 6px 10px;
  }


  #grid {
    display: grid;
    gap: 2px;
    border: 2px solid black;
    grid-template-columns: repeat(var(--grid-cols, 6), 50px);
    /* 기존 */
    grid-template-rows: repeat(var(--grid-rows, 6), 50px);
    touch-action: none;
    /* 추가 */
  }
  #gridContainer {
    flex-shrink: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 60px;
    /* 메뉴바 높이에 맞춰 조정 */
    box-sizing: border-box;
  }


  .toggle-key {
    display: block;
    margin: 6px 0;
    text-align: center;
    padding: 6px 8px;
    border: 1px solid #999;
    border-radius: 4px;
    background: #fafafa;
    cursor: pointer;
  }

  .toggle-key.active {
    background: #666;
    color: #fff;
  }

  .toggle-key {
    display: block;
    margin: 6px 0;
    text-align: center;
    padding: 6px 8px;
    border: 1px solid #999;
    border-radius: 4px;
    background: #fafafa;
    cursor: pointer;
  }

  .toggle-key.active {
    background: #666;
    color: #fff;
  }

  .cell {
    border: 1px solid #ccc;
    box-sizing: border-box;
    position: relative;
    background-color: white;
    width: 50px;
    height: 50px;
  }

  .cell.block {
    background-color: #e0e0ff;
    color: #003366;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .cell.wire {
    position: relative;
    background-color: #ffe;
  }

  /* ── 수직선 (│) 은 ::before 에만 그리기 ── */
  .cell.wire.wire-up::before,
  .cell.wire.wire-down::before {
    content: '';
    position: absolute;
    left: 50%;
    background-color: black;
    transform: translateX(-50%);
  }

  .cell.wire.wire-up::before {
    top: 0;
    height: 50%;
  }

  .cell.wire.wire-down::before {
    bottom: 0;
    height: 50%;
  }

  /* ── 수평선 (─) 은 ::after 에만 그리기 ── */
  .cell.wire.wire-left::after,
  .cell.wire.wire-right::after {
    content: '';
    position: absolute;
    top: 50%;
    background-color: black;
    transform: translateY(-50%);
  }

  .cell.wire.wire-left::after {
    left: 0;
    width: 50%;
  }

  .cell.wire.wire-right::after {
    right: 0;
    width: 50%;
  }

  /* ── 두 방향이 동시에 있을 땐 전체 길이로 ── */
  /* 세로 전체 (│) */
  .cell.wire.wire-up.wire-down::before {
    top: 0;
    height: 100%;
  }

  /* 가로 전체 (─) */
  .cell.wire.wire-left.wire-right::after {
    left: 0;
    width: 100%;
  }

  /* ── 배선 미리보기 강조 ── */
  .cell.wire-preview {
    background: #ffeca0;
  }

  /* ── 블록 아이콘 스타일 ── */
  .blockIcon {
    width: 60px;
    height: 30px;
    background-color: #e0e0ff;
    border: 1px solid #666;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    cursor: grab;
  }

  /* ── 휴지통 ── */
  #trash {
    width: 200px;
    height: 50px;
    margin: 20px auto;
    border: 2px dashed #F87171;
    background-color: #FEE2E2;
    color: #7F1D1D;
    font-weight: bold;
    display: flex;
    justify-content: center;
    align-items: center;
  }

  /* ── 4가지 코너 모양(ㄱ, ┐, └, ┘) 강제 반쪽 길이 ── */
  /* 세로선(│) – width만 4 ➜ 2 로 */
  /* 세로선(│) – 굵기만 2 px */
  .cell.wire.wire-up::before,
  .cell.wire.wire-down::before {
    width: 2px;
    /* ▽ 세로 점선 + 애니메이션 */
    background-image: repeating-linear-gradient(0deg, #000 0 26px, transparent 26px var(--unit));
    background-size: 100% var(--unit);
    animation: dash-down 1s linear infinite;
  }

  /* 가로선(─) – 굵기를 height 로만 통일 */
  .cell.wire.wire-left::after,
  .cell.wire.wire-right::after {
    height: 2px;
    /* ▽ 가로 점선 + 애니메이션 */
    background-image: repeating-linear-gradient(90deg, #000 0 26px, transparent 26px var(--unit));
    background-size: var(--unit) 100%;
    animation: dash-right 1s linear infinite;
  }

  /* ① 수평 흐름용 --------------------------------------------------- */

  /* 셀 크기 변수(선택) */
  :root {
    --unit: 52px;
    /* 셀 한 칸 간격 */
    /* 아래 네 값만 바꿔가며 테스트하세요 */
    --phase-right: 26px;
    /* →  흐름 */
    --phase-left: 0px;
    /* ←  흐름 (반 주기 만큼 밀어 예시) */
    --phase-down: 0px;
    /* ↓  흐름 */
    --phase-up: 26px;
    /* ↑  흐름 */
    /* shape: down+right (┌) */
    --corner-offset-dr-right: 0px;
    --corner-offset-dr-down: 0px;

    /* shape: down+left  (┐) */
    --corner-offset-dl-left: 26px;
    --corner-offset-dl-down: 26px;

    /* shape: up+right   (└) */
    --corner-offset-ur-right: 26px;
    --corner-offset-ur-up: 26px;

    /* shape: up+left    (┘) */
    --corner-offset-ul-left: 0px;
    --corner-offset-ul-up: 0px;

    /* fallback */
    --corner-offset: 0px;
    --half-unit: calc(var(--unit) / 2);
  }

  /* ── 가로 기본선(h) ───────────────────────── */
  .cell.wire.h:not(.corner)::after {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 100%;
    height: 2px;

    /* 검정 26px → 투명 26px = 총 52px */
    background-image: repeating-linear-gradient(90deg, #000 0 26px, transparent 26px var(--unit));
    background-size: var(--unit) 100%;
    /* 열 번호(col)만큼 -52px씩 당겨 패턴 이어붙이기 */
    background-position:
      calc(-1 * var(--unit) * var(--col) + var(--phase-right)) 0;
  }

  /* ── 세로 기본선(v) ───────────────────────── */
  .cell.wire.v:not(.corner)::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 100%;

    background-image: repeating-linear-gradient(0deg, #000 0 26px, transparent 26px var(--unit));
    background-size: 100% var(--unit);
    /* 행 번호(row)만큼 -52px씩 당겨 패턴 이어붙이기 */
    background-position:
      0 calc(-1 * var(--unit) * var(--row) + var(--phase-down));
  }




  @keyframes dash-right {
    from {
      background-position: calc(-1 * var(--unit) * var(--col) + var(--phase-right)) 0;
    }

    to {
      background-position: calc(-1 * var(--unit) * var(--col) + var(--phase-right) + var(--unit)) 0;
    }
  }

  @keyframes dash-left {
    from {
      background-position: calc(-1 * var(--unit) * var(--col) + var(--phase-left)) 0;
    }

    to {
      background-position: calc(-1 * var(--unit) * var(--col) + var(--phase-left) - var(--unit)) 0;
    }
  }

  @keyframes dash-down {
    from {
      background-position: 0 calc(-1 * var(--unit) * var(--row) + var(--phase-down));
    }

    to {
      background-position: 0 calc(-1 * var(--unit) * var(--row) + var(--phase-down) + var(--unit));
    }
  }

  @keyframes dash-up {
    from {
      background-position: 0 calc(-1 * var(--unit) * var(--row) + var(--phase-up));
    }

    to {
      background-position: 0 calc(-1 * var(--unit) * var(--row) + var(--phase-up) - var(--unit));
    }
  }





  /* 1) 애니메이션이 적용될 직선 셀은 배경색을 투명으로 */
  .cell.wire.h::after,
  .cell.wire.v::before {
    background-color: transparent;
    /* ≤ 점선 배경만 보이게 */
  }

  /* 2) 흐름 방향(flow-*)이 붙은 셀도 동일 */
  /* 코너엔 투명 처리하지 않는다 */
  .cell.wire.flow-right:not(.corner)::after,
  .cell.wire.flow-left:not(.corner)::after,
  .cell.wire.flow-down:not(.corner)::before,
  .cell.wire.flow-up:not(.corner)::before {
    background-color: transparent;
  }


  .cell.wire.h::after,
  .cell.wire.v::before {
    background-color: transparent;
  }

  .cell.wire.wire-up::before,
  .cell.wire.wire-down::before,
  .cell.wire.wire-left::after,
  .cell.wire.wire-right::after {
    background-color: transparent;
  }

  /* → 흐름 */
  .cell.wire.flow-right::after {
    /* 기존 */
    animation: dash-right 1s linear infinite;
    /* 위상 */
    background-position:
      calc(-1 * var(--unit) * var(--col) + var(--phase-right)) 0;
  }

  /* ← 흐름 */
  .cell.wire.flow-left::after {
    animation: dash-left 1s linear infinite;
    background-position:
      calc(-1 * var(--unit) * var(--col) + var(--phase-left)) 0;
  }

  /* ↓ 흐름 */
  .cell.wire.flow-down::before {
    animation: dash-down 1s linear infinite;
    background-position:
      0 calc(-1 * var(--unit) * var(--row) + var(--phase-down));
  }

  /* ↑ 흐름 */
  .cell.wire.flow-up::before {
    animation: dash-up 1s linear infinite;
    background-position:
      0 calc(-1 * var(--unit) * var(--row) + var(--phase-up));
  }

  .cell.wire.wire-up::before {
    background-position:
      0 calc(-1 * var(--unit) * var(--row) + var(--phase-up));
  }

  .cell.wire.wire-down::before {
    background-position:
      0 calc(-1 * var(--unit) * var(--row) + var(--phase-down));
  }

  .cell.wire.wire-left::after {
    background-position:
      calc(-1 * var(--unit) * var(--col) + var(--phase-left)) 0;
  }

  .cell.wire.wire-right::after {
    background-position:
      calc(-1 * var(--unit) * var(--col) + var(--phase-right)) 0;
  }

  /* ── 드래그된 state 에 따라 corner-offset 덮어쓰기 ── */
  /* shape down+right (┌) + flow-right */
  .cell.wire.corner.wire-down.wire-right.flow-right {
    --corner-offset: var(--corner-offset-dr-right);
  }

  /* shape down+right (┌) + flow-down */
  .cell.wire.corner.wire-down.wire-right.flow-down {
    --corner-offset: var(--corner-offset-dr-down);
  }

  /* shape down+left (┐) + flow-left */
  .cell.wire.corner.wire-down.wire-left.flow-left {
    --corner-offset: var(--corner-offset-dl-left);
  }

  /* shape down+left (┐) + flow-down */
  .cell.wire.corner.wire-down.wire-left.flow-down {
    --corner-offset: var(--corner-offset-dl-down);
  }

  /* shape up+right (└) + flow-right */
  .cell.wire.corner.wire-up.wire-right.flow-right {
    --corner-offset: var(--corner-offset-ur-right);
  }

  /* shape up+right (└) + flow-up */
  .cell.wire.corner.wire-up.wire-right.flow-up {
    --corner-offset: var(--corner-offset-ur-up);
  }

  /* shape up+left (┘) + flow-left */
  .cell.wire.corner.wire-up.wire-left.flow-left {
    --corner-offset: var(--corner-offset-ul-left);
  }

  /* shape up+left (┘) + flow-up */
  .cell.wire.corner.wire-up.wire-left.flow-up {
    --corner-offset: var(--corner-offset-ul-up);
  }

  /* ── 코너 셀 전용 keyframes ── */
  @keyframes dash-right-corner {
    from {
      background-position:
        calc(-1 * var(--unit) * var(--col) + var(--phase-right) - var(--corner-offset)) 0;
    }

    to {
      background-position:
        calc(-1 * var(--unit) * var(--col) + var(--phase-right) - var(--corner-offset) + var(--unit)) 0;
    }
  }

  @keyframes dash-left-corner {
    from {
      background-position:
        calc(-1 * var(--unit) * var(--col) + var(--phase-left) - var(--corner-offset)) 0;
    }

    to {
      background-position:
        calc(-1 * var(--unit) * var(--col) + var(--phase-left) - var(--corner-offset) - var(--unit)) 0;
    }
  }

  @keyframes dash-down-corner {
    from {
      background-position:
        0 calc(-1 * var(--unit) * var(--row) + var(--phase-down) - var(--corner-offset));
    }

    to {
      background-position:
        0 calc(-1 * var(--unit) * var(--row) + var(--phase-down) - var(--corner-offset) + var(--unit));
    }
  }

  @keyframes dash-up-corner {
    from {
      background-position:
        0 calc(-1 * var(--unit) * var(--row) + var(--phase-up) - var(--corner-offset));
    }

    to {
      background-position:
        0 calc(-1 * var(--unit) * var(--row) + var(--phase-up) - var(--corner-offset) - var(--unit));
    }
  }

  /* ── override: corner 에 새 keyframes 와 함께 animation 재정의 ── */

  /* ── 코너 셀 전용 override (흐름+모양 모두 체크) ── */
  /* → 흐름이면서 오른쪽 분기 코너 */
  .cell.wire.flow-right.corner.wire-right::after {
    animation: dash-right-corner 1s linear infinite;
    background-position:
      calc(-1 * var(--unit) * var(--col) + var(--phase-right) - var(--corner-offset)) 0;
  }

  /* ← 흐름이면서 왼쪽 분기 코너 */
  .cell.wire.flow-left.corner.wire-left::after {
    animation: dash-left-corner 1s linear infinite;
    background-position:
      calc(-1 * var(--unit) * var(--col) + var(--phase-left) - var(--corner-offset)) 0;
  }

  /* ↓ 흐름이면서 아래 분기 코너 */
  .cell.wire.flow-down.corner.wire-down::before {
    animation: dash-down-corner 1s linear infinite;
    background-position:
      0 calc(-1 * var(--unit) * var(--row) + var(--phase-down) - var(--corner-offset));
  }

  /* ↑ 흐름이면서 위 분기 코너 */
  .cell.wire.flow-up.corner.wire-up::before {
    animation: dash-up-corner 1s linear infinite;
    background-position:
      0 calc(-1 * var(--unit) * var(--row) + var(--phase-up) - var(--corner-offset));
  }

  #simulateButton {
    margin: 10px;
    padding: 8px 12px;
    border: none;
    border-radius: 4px;
    background-color: #4CAF50;
    color: white;
    font-size: 1rem;
    cursor: pointer;
  }

  #simulateButton:hover {
    background-color: #45a049;
  }

  /* INPUT 블록 클릭 시 포인터 표시 */
  .cell.block[data-type="INPUT"] {
    cursor: pointer;
  }

  /* OUTPUT 블록 강조 (결과 표시) */
  .cell.block[data-type="OUTPUT"] {
    font-weight: bold;
  }

  /* 활성(1) 상태 표시 (색각 이상 고려해 테두리 점선) */
  .cell.block.active {
    outline: 2px dashed currentColor;
    outline-offset: -2px;
  }

  #gradingTable {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
  }

  #gradingTable th,
  #gradingTable td {
    border: 1px solid #ccc;
    padding: 8px 12px;
    text-align: center;
  }

  #gradingTable th {
    background-color: #f9f9f9;
  }

  #gradingTable tr.correct td {
    background-color: #eaffea;
  }

  #gradingTable tr.wrong td {
    background-color: #ffeaea;
  }

  #gradingArea {
    width: 100%;
    max-width: 600px;
    background: #ffffff;
    border-top: 2px solid #ccc;
    margin-top: 20px;
    padding: 1.5rem;
    font-family: 'Noto Sans KR', sans-serif;
    font-size: 1rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    border-radius: 12px;
    text-align: left;
  }

  .gradeRow {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 6px 0;
    border-bottom: 1px solid #eee;
  }

  .gradeRow.correct::after {
    content: "✔️ 정답";
    color: green;
    font-weight: bold;
  }

  .gradeRow.wrong::after {
    content: "❌ 오답";
    color: red;
    font-weight: bold;
  }

  #gradeResultSummary {
    margin-top: 1rem;
    font-size: 1.2rem;
    font-weight: bold;
    text-align: center;
    color: #333;
  }

  #returnToEditBtn {
    margin-top: 1.5rem;
    padding: 10px 16px;
    background: #555;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
  }

  #returnToEditBtn:hover {
    background: #333;
  }

  #guestbookArea {
    margin-top: 2rem;
    padding: 1rem;
    background: #fffbe6;
    border: 1px solid #ccc;
    border-radius: 12px;
    max-width: 600px;
  }

  #guestbookArea textarea,
  #guestbookArea input {
    width: 100%;
    margin: 4px 0;
    padding: 8px;
    box-sizing: border-box;
  }

  .modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: white;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 999;
  }

  .modal-content {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
  }

  /* Chapter & Stage Screen */
  #chapterStageContainer {
    display: flex;
    gap: 1rem;
  }

  .chapter-list {
    width: 200px;
    border-right: 1px solid #ccc;
  }

  #stagePanel {
    flex: 1;
  }

  .chapterItem {
    padding: 0.5rem;
    cursor: pointer;
  }

  .chapterItem.selected {
    background: #e0e0ff;
    font-weight: bold;
  }

  .chapterItem.locked {
    color: #999;
    cursor: default;
  }

  .stage-list {
    flex: 1;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
  }

  .stageCard {
    position: relative;
    box-sizing: border-box;
    width: 200px;
    height: 125px;
    padding: 1rem;
    border: 1px solid #666;
    border-radius: 8px;
    background: #f5f5ff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    transition: transform 0.2s, box-shadow 0.2s;
  }

  .stageCard:not(.locked):hover {
    transform: scale(1.05);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
  }

  .stageCard.cleared {
    border-color: green;
  }

  .stageCard.cleared::after {
    content: '✓';
    position: absolute;
    top: 8px;
    right: 8px;
    color: green;
  }

  .stageCard.locked {
    opacity: 0.5;
    cursor: not-allowed;
  }

  .stageCard.locked::after {
    content: '🔒';
    position: absolute;
    top: 8px;
    right: 8px;
  }

  .btn-toggle {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    margin-left: 0.5rem;
  }

  .hidden {
    display: none;
  }

  .cell.block[data-type="JUNCTION"] {
    background-color: #ddd;
    font-weight: bold;
    color: #333;
  }

  .cell[data-type="JUNCTION"].error {
    border: 2px solid red;
    box-shadow: 0 0 6px red;
  }

  .modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100dvh;
    background-color: rgba(0, 0, 0, 0.4);
    /* ✅ 반투명 배경 */
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
  }

  .modal-content {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    max-width: 600px;
    width: 90%;
    text-align: center;
  }

  .modal-content h3 {
    margin-top: 0;
  }

  #shareText {
    font-family: monospace;
    resize: none;
  }

  #copyShareBtn, #closeShareBtn {
    margin-left: 0.5rem;
    padding: 0.5rem 1rem;
    font-size: 1rem;
  }

  /* style.css 맨 아래에 추가 */

  /* 튜토리얼 모달 배경을 살짝 더 어둡게 */
.tutorial-modal {
  background-color: rgba(0, 0, 0, 0.7);
  overflow-y: auto;
  padding: 1rem;
}

.tutorial-modal .tutorial-content {
  width: 100%;
  max-width: 600px;
  box-shadow: none;
  border-radius: 0;
  padding: 2rem;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: stretch;
  max-height: calc(100vh - 2rem);
  overflow-y: auto;
}

.tutorial-modal .tut-controls {
  margin-top: auto;
  display: flex;
  justify-content: center;
  gap: 0.5rem;
}

  /* 버튼 스타일 강조 */
  .tutorial-modal .tut-controls button {
    padding: 0.6rem 1.2rem;
    border-radius: 6px;
    font-weight: 500;
    transition: transform 0.1s ease;
  }

  .tutorial-modal .tut-controls button:hover {
    transform: scale(1.05);
  }

  .tutorial-img {
    width: 100%;
    max-height: 400px;
    object-fit: contain;
    margin: 1rem 0;
    border-radius: 4px;
  }

/* Ensure stage-specific tutorial modal is scrollable on small screens */
#stageTutorialModal {
  overflow-y: auto;
  padding: 1rem;
}

#stageTutorialModal .modal-content {
  max-height: calc(100vh - 2rem);
  overflow-y: auto;
}

#gifModal {
  overflow-y: auto;
  padding: 1rem;
}

#gifModal .modal-content {
  max-height: calc(100vh - 2rem);
  overflow-y: auto;
}

  /* ── ① 공통: 페이지 전체 배경 (비게임·게임 모두) ── */
  html, body {
    height: 100%;
    margin: 0;
  }

  body {
    /* assets/background.png 파일을 프로젝트 루트 기준으로 불러옵니다 */
    font-family: 'Noto Sans KR', sans-serif;
    text-align: center;
  }

  body:not(.game-active) {
    background: url('assets/background.png') center center / cover no-repeat fixed;
  }

  /* ── ② 비게임 화면에만 “흰 배경 + 블러” 오버레이 적용 ── */
  /* ── 비게임 화면에만 오버레이 적용 ── */
  body:not(.game-active) #mainScreen,
  body:not(.game-active) #chapterStageScreen {
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(8px);
    border-radius: 12px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
    padding: 2rem;
    margin: 2rem auto;
    box-sizing: border-box;
  }

  /* ── 게임 화면에서는 오버레이 완전 해제 ── */
  body.game-active #gameScreen {
    background: none !important;
    backdrop-filter: none !important;
    box-shadow: none !important;
    margin: 0 !important;
    padding: 0 !important;
    background-image: none !important;
    background-color: #f0f0f0 !important;
  }

  .container {
    display: flex;
    gap: 5rem;
  }

  .item {
    width: 100px;
    height: 100px;
    background-color: lightblue;
    margin: 5px;
  }

  #gridContainer {
    position: relative;
    /* 중복되어도 무방 */
  }

  #gridOverlay {
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.6);
    z-index: 1000;
    cursor: not-allowed;
  }

  #problemGridOverlay {
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.6);
    z-index: 1000;
    cursor: not-allowed;
  }

  .blockIcon {
    position: relative;
  }

  /* hover 시에만 ::after 가 나타나서 내용 표시 */
  #blockPanel .blockIcon:hover::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: #333;
    color: #fff;
    padding: 4px 8px;
    z-index: 1001;
    border-radius: 4px;
    font-size: 12px;
    white-space: nowrap;
    pointer-events: none;
  }

  /* 랭킹 모달 전용 중앙정렬 오버라이드 */
  #rankingModal {
    position: fixed !important;
    /* 뷰포트 기준 */
    top: 0 !important;
    left: 0 !important;
    width: 100vw !important;
    height: 100dvh !important;
    display: none;
    /* flex로 중앙 배치 */
    justify-content: center !important;
    align-items: center !important;
    background-color: rgba(0, 0, 0, 0.4) !important;
    /* 반투명 오버레이 */
    z-index: 10000 !important;
    /* 전역 모달보다 위에 */
  }

  #rankingModal .modal-content {
    /* 내용 크기에 맞춰 자동 조절 */
    display: inline-block !important;
    margin: auto !important;
    /* 뷰포트 기준 최대 폭/높이 설정 */
    max-width: 90vw !important;
    max-height: 80vh !important;
    width: auto !important;
    padding: 1.5rem !important;
    box-sizing: border-box !important;
    /* 세로 overflow 시 스크롤 */
    overflow-y: auto !important;
  }

  /* ── Username Modal: input & button 디자인 개선 ── */
  #usernameModal .modal-content input#usernameInput {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 1px solid #ccc;
    border-radius: 8px;
    margin: 0.5rem 0 1rem;
    box-sizing: border-box;
    transition: border-color 0.2s ease;
  }

  #usernameModal .modal-content input#usernameInput:focus {
    outline: none;
    border-color: #6b8cff;
  }

  /* 확인 버튼 */
  #usernameModal .modal-content button#usernameSubmit {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    color: #fff;
    background: linear-gradient(135deg, #6B8CFF 0%, #88E0EF 100%);
    border: none;
    border-radius: 8px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: transform 0.1s ease, box-shadow 0.2s ease;
  }

  #usernameModal .modal-content button#usernameSubmit:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
  }

  #usernameModal .modal-content button#usernameSubmit:active {
    transform: translateY(0);
    box-shadow: 0 3px 6px rgba(0, 0, 0, 0.1);
  }

  #usernameModal .modal-content button#usernameSubmit:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(107, 140, 255, 0.5);
  }

  #usernameModal .modal-content .info-text {
    margin: 0.25rem 0;
    font-size: 0.9rem;
    color: #555;
  }

  /* ── 랭킹 테이블 스타일 ── */
  #rankingList table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
    font-size: 0.95rem;
  }

  #rankingList th,
  #rankingList td {
    padding: 0.75rem 0.5rem;
    border-bottom: 1px solid #ddd;
    text-align: center;
  }

  #rankingList thead th {
    background-color: #C6C9ED;
    color: #0F172A;
    font-weight: 600;
  }

  .rankingTableWrapper {
    max-height: 400px;
    overflow-y: auto;
    margin-bottom: 1rem;
  }

  .rankingTable {
    width: 100%;
    border-collapse: collapse;
  }

  .rankingTable th,
  .rankingTable td {
    padding: 6px 12px;
    border: 1px solid #ccc;
    text-align: center;
  }

  /* 랭킹 모달 콘텐츠 개선 */
  #rankingModal .modal-content {
    padding: 1.5rem;
    max-width: 700px;
    width: 95%;
    border-radius: 12px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
  }

  #rankingModal .modal-content h2 {
    margin-top: 0;
    font-size: 1.6rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  /* 버튼 그룹 */
  #rankingModal .modal-buttons {
    margin-top: 1rem;
    text-align: right;
  }

  #rankingModal .modal-buttons button {
    padding: 0.5rem 1rem;
    font-size: 0.95rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: transform 0.1s ease, box-shadow 0.2s ease;
  }

  #rankingModal .modal-buttons button#refreshRankingBtn {
    background: #eef6ff;
    color: #3366cc;
  }

  #rankingModal .modal-buttons button#closeRankingBtn {
    background: #ddd;
    color: #333;
  }

  #rankingModal .modal-buttons button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  }

  #rankingModal .modal-buttons button:active {
    transform: translateY(0);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  }

  .modal.active {
    display: flex !important;
  }

  .cell[data-type="OUTPUT"].error {
    border: 2px solid red;
    box-shadow: 0 0 6px red;
  }

  #overallRankingArea {
    width: 350px;
    background-color: #fff;
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    text-align: left;
    max-height: 600px;
    /* 원하는 최대 높이로 조정 */
    display: flex;
    flex-direction: column;
  }

  #overallRankingArea h3 {
    margin-bottom: 0.5rem;
  }

  #overallRankingList {
    margin-top: 1rem;
    flex: 1;
    /* 남은 공간 전부 사용 */
    overflow-y: auto;
    /* 세로 스크롤 */
  }

  #overallRankingList table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
  }

  #overallRankingList th,
  #overallRankingList td {
    padding: 0.5rem;
    border-bottom: 1px solid #ddd;
    text-align: center;
  }

  #overallRankingList thead th {
    background-color: #C6C9ED;
    color: #0F172A;
  }

  #firstScreen {
    /* 이전: .container { display:flex; gap:5rem; } 에서만 정의되어 있었음 */
    min-height: 100vh;
    justify-content: center;
    /* 가로 중앙 정렬 */
    align-items: flex-start;
    /* 세 카드의 상단을 같은 높이에 맞춤 */
  }

  #chapterStageScreen {
    min-height: auto;
    overflow-y: auto;
  }

  #module-editor-screen {
    min-height: 100vh;
  }

  /* ② 메인 카드(#mainScreen) 가 가진 margin:auto 를 수직 여백만 남기도록 변경 */
  #firstScreen>#mainScreen {
    /* 이전: body:not(.game-active) #mainScreen { margin: 2rem auto; } */
    margin: 2rem 0;
    /* 위아래 2rem, 좌우 0 */
  }

  /* ③ 전체 랭킹 카드도 위쪽 여백을 주어 높이를 맞춰 줌 */
  #firstScreen>#overallRankingArea {
    /* 이전: margin-top 이 전혀 없었음 */
    margin-top: 2rem;
  }

  #clearedModal .rankingTable tr.highlight {
    background-color: #ffffcc;
    /* 연노란색 배경 */
  }

  #clearedModal .rankingTableWrapper {
    max-height: 60vh;
    overflow-y: auto;
    margin-bottom: 1rem;
  }

  #clearedModal .modal-content #clearedRanking {
    max-height: 60vh;
    /* 화면 높이의 60%를 최대 높이로 설정 */
    overflow-y: auto;
    /* 세로 스크롤 허용 */
    padding-right: 0.5rem;
    /* 스크롤바와 내용 사이 여유 */
    box-sizing: border-box;
  }

  /* modal 하단의 이전/다음 스테이지 버튼 디자인 개선 */
  .modal-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
  }

  .modal-buttons button {
    background-color: #007bff;
    /* 기본 파란색 배경 */
    color: #fff;
    /* 흰 글씨 */
    border: none;
    padding: 0.6rem 1.2rem;
    /* 버튼 크기 조정 */
    border-radius: 4px;
    /* 둥근 모서리 */
    font-size: 1rem;
    cursor: pointer;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    transition: background-color 0.2s, transform 0.1s;
  }

  .modal-buttons button:hover {
    background-color: #0056b3;
    /* 호버 시 진해지는 파랑 */
  }

  .modal-buttons button:active {
    transform: translateY(1px);
    /* 클릭 시 살짝 눌린 느낌 */
  }

  .modal-buttons button:disabled {
    background-color: #cccccc;
    /* 비활성화 상태 */
    cursor: not-allowed;
  }

  #clearedModal .modal-content {
    position: relative;
    /* closeBtn 절대 위치를 위해 추가 */
  }

  #clearedModal .closeBtn {
    position: absolute;
    top: 0.75rem;
    /* 모달 상단에서 */
    right: 0.75rem;
    /* 모달 우측에서 */
    background: transparent;
    border: none;
    font-size: 1.5rem;
    /* 버튼 크기 */
    line-height: 1;
    width: 2.5rem;
    /* 버튼 크기 조정 (가로) */
    height: 2.5rem;
    /* 버튼 크기 조정 (세로) */
    padding: 0.25rem;
    cursor: pointer;
    border-radius: 50%;
    /* 둥근 버튼 */
    transition: background 0.2s, transform 0.1s, color 0.2s;
  }

  #clearedModal .closeBtn:hover {
    background: rgba(0, 0, 0, 0.1);
    /* 호버 시 살짝 배경 */
  }

  #clearedModal .closeBtn:active {
    transform: scale(0.9);
    /* 클릭 시 눌린 느낌 */
  }

  #clearedModal .closeBtn:focus {
    outline: none;
    /* 포커스 아웃라인 제거 */
  }

  #module-editor-screen {
  display: none;
  padding: 2rem;
  background-color: #fff;
  border: 2px solid #666;
  max-width: 600px;
  margin: 2rem auto;
}

#moduleGrid,
#problemGrid {
  display: grid;
  gap: 2px;
  border: 2px solid black;
  grid-template-columns: repeat(var(--grid-cols, 6), 50px);
  grid-template-rows: repeat(var(--grid-rows, 6), 50px);
  touch-action: none;
}

/* 공통: 게임 모드 · 모듈 모드 블록 패널 모두에 적용 */
#blockPanel,
#moduleBlockPanel,
#problemBlockPanel {
  display: flex;               /* 세로 정렬을 위해 flex 사용 */
  flex-direction: column;      /* 수직 방향으로 블록 나열 */
  align-items: stretch;        /* 폭을 부모에 맞춤 */
  gap: 0.75rem;                /* 블록 간격: 원하시는 px/em 단위로 조정 가능 */
  padding: 0.5rem 0;           /* 상하 여백(옵션) */
}

/* 블록 아이콘 크기·정렬 (필요시 조정) */
#blockPanel .blockIcon,
#moduleBlockPanel .blockIcon,
#problemBlockPanel .blockIcon {
  width: 100%;                 /* 패널 폭에 꽉 차도록 */
  text-align: center;          /* 텍스트 중앙 정렬 */
}

/* ── 화면(.screen) 공통 ── */
.screen {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  min-height: 100vh;
  background: rgba(255,255,255,0.95);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 2rem;
  overflow-y: auto;
  box-sizing: border-box;
  font-family: 'Noto Sans KR', sans-serif;
}

/* 뒤로가기 버튼 */
.btn-back {
  align-self: flex-start;
  margin-bottom: 1rem;
  padding: 0.5rem 1rem;
  border: 1px solid #999;
  background: #fafafa;
  cursor: pointer;
}

/* 화면 제목 */
.module-management-screen .screen-title {
  margin: 0;
  font-size: 1.5rem;
  font-weight: bold;
  margin-bottom: 1.5rem;
}

/* 모듈 목록 */
.module-list {
  list-style: none;
  padding: 0;
  margin: 0;
  width: 100%;
  max-width: 360px;
  border: 1px solid #ddd;
  border-radius: 4px;
  overflow: hidden;
}

.module-list .module-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid #eee;
}

.module-list .module-item:last-child {
  border-bottom: none;
}

/* 사용자 문제 목록 */
.problem-list {
  list-style: none;
  padding: 0;
  margin: 0 auto;
  width: 100%;
  max-width: 600px;
  border: 1px solid #ddd;
  border-radius: 4px;
  overflow: hidden;
}

.problem-list .problem-item {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid #eee;
  cursor: pointer;
}

.problem-list .problem-item:last-child {
  border-bottom: none;
}

.module-item .module-name {
  font-size: 1rem;
  color: #333;
  word-break: break-all;
}

/* 불러오기 버튼 */
.btn-load {
  padding: 0.4rem 0.8rem;
  border: 1px solid #008cba;
  background: #00aaff;
  color: white;
  border-radius: 3px;
  cursor: pointer;
  font-size: 0.9rem;
}

.btn-load:hover {
  background: #008cba;
}

/* 새 모듈 만들기 버튼 */
.btn-primary {
  margin-top: 1.5rem;
  padding: 0.75rem 1.5rem;
  border: none;
  background: #28a745;
  color: white;
  border-radius: 4px;
  font-size: 1rem;
  cursor: pointer;
}

.btn-primary:hover {
  background: #218838;
}

/* ────────────────────────────────
   Modal (모달) 기본 스타일
──────────────────────────────── */

/* 모달 전체 컨테이너 */
.modal {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  display: none;             /* 처음엔 숨김 */
  align-items: center;       /* 세로 중앙 정렬 */
  justify-content: center;   /* 가로 중앙 정렬 */
  z-index: 1000;             /* 다른 요소들 위에 */
}

/* 백드롭: 반투명 검정 */
.modal-backdrop {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0, 0, 0, 0.5);
}

/* 다이얼로그 박스 */
.modal-dialog {
  position: relative;
  background: #fff;
  padding: 1.5rem;
  width: 260px;
  max-width: 90%;
  border-radius: 6px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
  z-index: 1001; /* backdrop 위에 */
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

/* 제목 */
.modal-dialog h3 {
  margin: 0;
  font-size: 1.2rem;
  text-align: center;
}

/* 입력창 스타일 */
.modal-input,
.modal-textarea {
  width: 100%;
  padding: 0.5rem;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 0.95rem;
  box-sizing: border-box;
}

/* 버튼 그룹 (가로 정렬) */
.modal-buttons {
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

/* primary 버튼 (저장) */
.btn-primary {
  padding: 0.5rem 1rem;
  border: none;
  background: #28a745;
  color: #fff;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.95rem;
}

.btn-primary:hover {
  background: #218838;
}

/* secondary 버튼 (취소) */
.btn-secondary {
  padding: 0.5rem 1rem;
  border: 1px solid #999;
  background: #f5f5f5;
  color: #333;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.95rem;
}

.btn-secondary:hover {
  background: #e0e0e0;
}

/* 삭제 버튼 */
.deleteProbBtn {
  padding: 0.4rem 0.8rem;
  border: 1px solid #dc3545;
  background: #f8d7da;
  color: #dc3545;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.9rem;
}

.deleteProbBtn:hover {
  background: #f1b0b7;
}

/* ------------------------------------------------------------------
   🔧 GRID 시각 개선
------------------------------------------------------------------ */


/* ------------------------------------------------------------------
   📐 각 셀의 모서리를 둥글게 만들기
------------------------------------------------------------------ */

/* ── 1) 기본 셀 ── */
.cell {
  width: 50px;
  height: 50px;
  background-color: #ffffff;
  border-radius: 3px;             /* 🎯 핵심 – 4~6px 권장 */
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.4);
  overflow: hidden;               /* 내부 요소가 모서리 밖으로 튀지 않도록 */
}


/* ── 3) 외곽 테두리도 통일 ── */
#grid {
  border-radius: 5px;            /* 그리드 바깥도 살짝 더 둥글게 */
}

/* ------------------------------------------------------------------
   🪄 타일 입체감 & 호버 리프트
------------------------------------------------------------------ */

/* ── 1) 전체 그리드 박스 ── */
#grid {
  /* 테두리는 그대로 두고 그림자만 강화 */
  border: 2px solid #666;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.10);
}

/* ── 2) 기본 셀 ── */
.cell.block {
  border-radius: 3px;

  /* 🔹 다중 그림자: 윗면 밝게 + 아랫면 어둡게 + 살짝 떠 있는 그림자 */
  box-shadow:
    inset 0 1px 2px rgba(255, 255, 255, 0.8),   /* 위·왼쪽 빛받은 면 */
    inset 0 -1px 2px rgba(0, 0, 0, 0.06),       /* 아래·오른쪽 음영 */
    0 1px 2px rgba(0, 0, 0, 0.07);              /* 바닥 그림자 */

  transition: transform 120ms ease, box-shadow 120ms ease;
}

/* ── 3) 마우스오버 리프트 ── */
.cell.block:hover {
  transform: translateY(-1px);
  box-shadow:
    inset 0 1px 2px rgba(255, 255, 255, 0.85),
    inset 0 -1px 2px rgba(0, 0, 0, 0.07),
    0 4px 8px rgba(0, 0, 0, 0.10);              /* 조금 더 길어진 바닥 그림자 */
  cursor: pointer;
}

/* ── 4) 클릭(드래그) 중 압박감 ── */
.cell:active {
  transform: translateY(0);                     /* 내려앉음 */
  box-shadow:
    inset 0 1px 2px rgba(255, 255, 255, 0.7),
    inset 0 -1px 2px rgba(0, 0, 0, 0.05),
    0 1px 2px rgba(0, 0, 0, 0.08);
}

#userProblemTable {
  width: 100%;
  max-width: 600px;
  border-collapse: collapse;
  margin-top: 1rem;
  background: rgba(255, 255, 255, 0.8);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

#userProblemTable th,
#userProblemTable td {
  padding: 0.5rem;
  border: 1px solid #ccc;
  text-align: center;
}

#userProblemTable th {
  font-weight: 600;
}

#userProblemTable td.probTitle {
  cursor: pointer;
  text-align: left;
}

.likeBtn {
  border: none;
  background: #eee;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 1rem;
}

.likeBtn:hover {
  background: #ddd;
}

#openProblemCreatorBtn {
  margin-top: auto;
  background: #007bff;
  color: #fff;
}

#openProblemCreatorBtn:hover {
  background: #0069d9;
}

#userProblemTable tbody tr:hover {
  background-color: #f0f8ff;
}

#userProblemTable tbody tr.solved {
  background-color: #e6ffe6;
}

#hintButtons {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
}

/* Hint modal buttons */
#hintButtons button {
  width: 100px;
  height: 100px;
  font-size: 1rem;
  margin: 0.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
#hintButtons .lock-icon {
  margin-top: 0.25rem;
}
#hintButtons button.open {
  background-color: #87CEFA;
}
#hintButtons button.available {
  background-color: #90EE90;
}

#hintTimerContainer {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  align-items: center;
}

/* ----- Loading Screen ----- */
#loadingScreen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: #f0f0f0;
  z-index: 9999;
}

.loader {
  border: 8px solid #e0e0e0;
  border-top: 8px solid #3b82f6;
  border-radius: 50%;
  width: 64px;
  height: 64px;
  animation: spin 1s linear infinite;
  margin-bottom: 1rem;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* ----- Saved circuit thumbnails ----- */
.saved-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 0;
}

.saved-item {
  border: 2px solid #ccc;
  padding: 4px;
  width: 120px;
  cursor: pointer;
  position: relative;
  text-align: center;
  background: #fff;
}

.saved-item img {
  width: 100%;
  height: auto;
  display: block;
}

.saved-item .deleteBtn {
  position: absolute;
  top: 4px;
  right: 4px;
}

.saved-caption {
  font-size: 12px;
  margin-top: 4px;
}