:root {
  --color-primary: #4F86C6;
  --color-primary-dark: #3A6DA8;
  --color-accent: #FF9F5B;
  --color-know: #4CAF7D;
  --color-dontknow: #E8785A;
  --color-danger: #D9534F;
  --color-bg: #FBF8F3;
  --color-card: #FFFFFF;
  --color-text: #2E2A26;
  --color-text-muted: #7A756E;
  --color-border: #EAE3D8;

  /* spacing */
  --space-1: 4px; --space-2: 8px; --space-3: 12px; --space-4: 16px;
  --space-5: 24px; --space-6: 32px; --space-7: 48px;
  /* radius */
  --radius-sm: 10px; --radius-md: 16px; --radius-lg: 22px;
  /* shadow (레이어드) */
  --shadow-sm: 0 1px 2px rgba(28,25,20,.05);
  --shadow-md: 0 1px 2px rgba(28,25,20,.05), 0 6px 16px rgba(28,25,20,.07);
  /* type scale */
  --text-xs: 12px; --text-sm: 14px; --text-base: 16px; --text-lg: 20px;
  --text-xl: 22px; --text-2xl: 30px; --text-3xl: 40px;

  --safe-top: env(safe-area-inset-top, 0px);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
  -webkit-tap-highlight-color: transparent;
  overscroll-behavior-y: contain;
}

#app {
  min-height: 100%;
  display: flex;
  flex-direction: column;
}

#topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: calc(14px + var(--safe-top)) 18px 14px;
  background: var(--color-primary);
  color: white;
  position: sticky;
  top: 0;
  z-index: 10;
}

#topbar h1 {
  font-size: var(--text-lg);
  margin: 0;
  flex: 1;
  text-align: center;
}

.icon-btn {
  background: rgba(255,255,255,0.18);
  border: none;
  color: white;
  font-size: var(--text-xl);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}
.icon-btn:active { background: rgba(255,255,255,0.32); }

#screen-root {
  flex: 1;
  padding: 20px 20px calc(28px + var(--safe-bottom));
  max-width: 640px;
  width: 100%;
  margin: 0 auto;
}

.screen { display: none; }
.screen.active { display: block; animation: slide-in-right .22s cubic-bezier(0.22, 0.61, 0.36, 1); }
/* 뒤로가기 방향일 때는 #screen-root에 dir-back 클래스를 붙여 반대쪽에서 슬라이드 인 */
#screen-root.dir-back .screen.active { animation-name: slide-in-left; }

@keyframes fadein { from { opacity: 0; transform: translateY(6px);} to { opacity:1; transform: translateY(0);} }
@keyframes slide-in-right { from { opacity: 0; transform: translateX(28px); } to { opacity: 1; transform: translateX(0); } }
@keyframes slide-in-left { from { opacity: 0; transform: translateX(-28px); } to { opacity: 1; transform: translateX(0); } }

@media (prefers-reduced-motion: reduce) {
  .screen.active, .lcwc-phase { animation: none; }
}

/* [디자인팀 임시 미리보기] 로고 배너 후보 적용 테스트용 — 되돌릴 때 이 블록만 삭제 */
.brand-banner-preview { margin: 0 0 var(--space-3); text-align: center; }
.brand-banner-preview img {
  max-width: 100%;
  width: 100%;
  height: auto;
  max-height: 160px;
  object-fit: contain;
  display: block;
  margin: 0 auto;
}

/* 홈 화면 */
.home-hero { display:flex; justify-content:center; margin: var(--space-2) 0 20px; }
.streak-badge {
  background: linear-gradient(135deg, #FFD79A, #FF9F5B);
  color: #5C3A0E;
  padding: 14px 26px;
  border-radius: 999px;
  font-size: var(--text-lg);
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  box-shadow: var(--shadow-md);
}
.streak-fire { font-size: 24px; }
.streak-label { font-size: 15px; font-weight: 500; }

/* 학습 달력(히트맵) */
.heatmap-card {
  background: var(--color-card);
  border: 1px solid rgba(0,0,0,.045);
  border-radius: var(--radius-lg);
  padding: 16px 18px;
  box-shadow: var(--shadow-md);
  margin-bottom: 22px;
}
.heatmap-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}
.heatmap-title { font-weight: 700; font-size: 15px; }
.heatmap-total { font-size: 13px; color: var(--color-text-muted); font-weight: 600; }

.heatmap-scroll {
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  padding-bottom: 4px;
}
.heatmap-inner { display: flex; gap: 6px; width: max-content; }
.heatmap-daylabels {
  display: flex;
  flex-direction: column;
  gap: 3px;
  flex-shrink: 0;
  padding-top: 15px; /* 월 라벨 높이만큼 아래로 */
}
.heatmap-daylabels span {
  height: 13px;
  line-height: 13px;
  font-size: 10px;
  color: var(--color-text-muted);
}
.heatmap-body { display: flex; flex-direction: column; }
.heatmap-months {
  display: flex;
  gap: 3px;
  height: 15px;
}
.heatmap-month-label {
  width: 13px;
  flex-shrink: 0;
  font-size: 10px;
  color: var(--color-text-muted);
  font-weight: 700;
  white-space: nowrap;
  overflow: visible;
}
.heatmap-grid { display: flex; gap: 3px; }
.heatmap-week { display: flex; flex-direction: column; gap: 3px; }
.heatmap-cell {
  width: 13px;
  height: 13px;
  border-radius: 4px;
  background: var(--color-border);
}
.heatmap-cell.empty { background: var(--color-border); }
.heatmap-cell.future { background: transparent; border: 1px dashed var(--color-border); }
.heatmap-cell.studied { background: var(--color-know); }
.heatmap-cell.today { box-shadow: 0 0 0 2px var(--color-accent); }
.heatmap-legend {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 10px;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}
.heatmap-legend .heatmap-cell { width: 12px; height: 12px; }

.progress-card {
  background: var(--color-card);
  border: 1px solid rgba(0,0,0,.045);
  border-radius: var(--radius-lg);
  padding: 18px 20px;
  box-shadow: var(--shadow-md);
  margin-bottom: 22px;
}
.progress-row { display:flex; justify-content:space-between; align-items:center; margin: 6px 0; font-size: 15px; }
.progress-label { color: var(--color-text-muted); font-weight: 600; }
.progress-bar {
  background: var(--color-border);
  border-radius: 999px;
  height: 10px;
  overflow: hidden;
  margin-bottom: 14px;
}
.progress-fill {
  height: 100%;
  width: 100%;
  border-radius: 999px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .3s ease;
}
.progress-fill.learn { background: var(--color-primary); }
.progress-fill.master { background: var(--color-accent); }
.progress-fill.review { background: var(--color-primary); }
.progress-fill.new { background: var(--color-primary); }
.progress-fill.lcwc { background: var(--color-primary); }
.progress-fill.final { background: var(--color-accent); }
.progress-fill.diag { background: var(--color-primary); }

.button-stack { display:flex; flex-direction:column; gap: var(--space-3); }

.btn {
  border: none;
  border-radius: var(--radius-md);
  padding: 14px 18px;
  font-size: 17px;
  font-weight: 700;
  cursor: pointer;
  color: white;
  background: var(--color-primary);
  transition: transform .09s ease, box-shadow .09s ease, opacity .15s ease;
}
.btn:active { transform: scale(0.97); }
.btn-xl { padding: 20px; font-size: 19px; border-radius: var(--radius-lg); min-height: 64px; }
.btn-primary { background: var(--color-primary); box-shadow: 0 4px 0 var(--color-primary-dark); }
.btn-secondary { background: #7EB0E5; box-shadow: 0 4px 0 color-mix(in srgb, #7EB0E5 70%, black); }
.btn-ghost { background: transparent; color: var(--color-primary-dark); font-weight: 600; padding: 10px; }
.btn-danger { background: var(--color-danger); box-shadow: 0 4px 0 color-mix(in srgb, var(--color-danger) 70%, black); }
.btn-know { background: var(--color-know); box-shadow: 0 4px 0 color-mix(in srgb, var(--color-know) 70%, black); }
.btn-dontknow { background: var(--color-dontknow); box-shadow: 0 4px 0 color-mix(in srgb, var(--color-dontknow) 70%, black); }
.btn:disabled { opacity: .5; }

/* Duolingo식 단색 하단 그림자 + 눌림 효과 (채움색 버튼에만 적용, ghost/옵션 버튼 제외) */
.btn-primary:active, .btn-secondary:active, .btn-know:active, .btn-dontknow:active, .btn-danger:active {
  transform: translateY(3px);
}
.btn-primary:active { box-shadow: 0 1px 0 var(--color-primary-dark); }
.btn-secondary:active { box-shadow: 0 1px 0 color-mix(in srgb, #7EB0E5 70%, black); }
.btn-know:active { box-shadow: 0 1px 0 color-mix(in srgb, var(--color-know) 70%, black); }
.btn-dontknow:active { box-shadow: 0 1px 0 color-mix(in srgb, var(--color-dontknow) 70%, black); }
.btn-danger:active { box-shadow: 0 1px 0 color-mix(in srgb, var(--color-danger) 70%, black); }

/* 세션 스텝 인디케이터 (워밍업/신규단어/손글씨훈련/확인테스트) */
.step-indicator {
  display: flex;
  gap: var(--space-2);
  max-width: 640px;
  margin: 0 auto;
  padding: 0 20px var(--space-3);
}
.step-seg {
  flex: 1;
  height: 6px;
  border-radius: 999px;
  background: var(--color-border);
  transform: scaleY(1);
  transition: background-color .2s ease, transform .2s ease;
}
.step-seg.done { background: var(--color-primary); }
.step-seg.current { background: var(--color-primary); transform: scaleY(1.5); }

/* 오늘의 학습 경과시간 표시 (스텝 인디케이터 바로 아래) */
.session-timer {
  max-width: 640px;
  margin: -6px auto 0;
  padding: 0 20px var(--space-3);
  text-align: center;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  letter-spacing: .2px;
}

.hint-text { color: var(--color-text-muted); font-size: var(--text-sm); text-align:center; line-height:1.5; }
.prompt-text { text-align:center; font-size: 17px; font-weight: 600; margin: 14px 0; }
.prompt-text-lg { text-align:center; font-size: var(--text-lg); font-weight: 700; line-height: 1.6; }
.step-caption {
  display: table;
  margin: 0 auto 14px;
  background: #EFF5FC;
  color: var(--color-primary-dark);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: .04em;
  padding: 6px 16px;
  border-radius: 999px;
}

/* 카드 (단어 노출/진단/LCWC 공용) */
.flash-card {
  background: var(--color-card);
  border: 1px solid rgba(0,0,0,.045);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 40px 24px;
  text-align: center;
  margin: 18px auto;
  min-height: 200px;
  max-width: 540px;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;
}
.flash-word { font-size: var(--text-3xl); font-weight: 800; color: var(--color-primary-dark); word-break: break-word; }
.flash-meaning { font-size: var(--text-xl); color: var(--color-text); }

/* 단어 이미지 - 이미지가 없는 단어는 img가 hidden 처리되어 레이아웃에 아무 자리도 차지하지 않는다 */
.flash-image {
  width: 140px;
  height: 140px;
  object-fit: contain;
  border-radius: var(--radius-md);
  background: #F5F8FC;
}

.speak-btn {
  background: #EFF5FC;
  color: var(--color-primary-dark);
  border: none;
  border-radius: 999px;
  padding: 10px 20px;
  font-size: 15px;
  font-weight: 700;
  margin-top: var(--space-1);
}
.speak-btn:active { background: #DCEBFA; }
.speak-btn .speak-icon { display: inline-block; }
.speak-btn.speaking .speak-icon { animation: speak-pulse .8s ease-in-out infinite; }
@keyframes speak-pulse { 0%, 100% { opacity: 1; } 50% { opacity: .4; } }

.choice-row { display:flex; gap: var(--space-3); margin-top: 10px; }
.choice-row .btn { flex: 1; }

.diag-progress-wrap { margin-bottom: var(--space-1); }

/* 진단 스킵 테스트 (즉답형 4지선다) */
.diag-word-card { min-height: 130px; padding: 30px 24px; margin-bottom: 14px; }
.diag-options { display: flex; flex-direction: column; gap: var(--space-3); margin-bottom: var(--space-4); }
.diag-option-btn {
  width: 100%;
  color: var(--color-text);
  background: var(--color-card);
  border: 2px solid var(--color-border);
  text-align: center;
  min-height: 58px;
  font-size: 17px;
  box-shadow: none;
  transform: none;
}
.diag-option-btn:active { transform: scale(0.98); }
.diag-option-btn.dont-know {
  background: transparent;
  border: 2px dashed var(--color-border);
  color: var(--color-text-muted);
  font-weight: 600;
}
.diag-option-btn.correct { background: #D9F0E2; border-color: var(--color-know); animation: option-pop .15s cubic-bezier(0.34, 1.56, 0.64, 1); }
.diag-option-btn.wrong { background: #FBE1DA; border-color: var(--color-dontknow); animation: option-shake .2s ease; }
.diag-option-btn:disabled { opacity: 1; }

/* 퀴즈 */
.quiz-card {
  background: var(--color-card);
  border: 1px solid rgba(0,0,0,.045);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 26px 22px;
  margin: 10px auto 0;
  max-width: 540px;
  width: 100%;
}
.quiz-question { font-size: var(--text-2xl); font-weight: 800; text-align:center; color: var(--color-primary-dark); margin-bottom: 8px; word-break: break-word;}
.options-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-3); margin-top: var(--space-4); }
.option-btn {
  background: var(--color-card);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 16px 10px;
  font-size: var(--text-base);
  font-weight: 600;
  min-height: 64px;
  cursor: pointer;
}
.option-btn:active { transform: scale(0.98); }
.option-btn.correct { background: #D9F0E2; border-color: var(--color-know); animation: option-pop .15s cubic-bezier(0.34, 1.56, 0.64, 1); }
.option-btn.wrong { background: #FBE1DA; border-color: var(--color-dontknow); animation: option-shake .2s ease; }

@keyframes option-pop {
  0% { transform: scale(1); }
  50% { transform: scale(1.04); }
  100% { transform: scale(1); }
}
@keyframes option-shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  50% { transform: translateX(6px); }
  75% { transform: translateX(-4px); }
}

.feedback { text-align:center; font-weight: 700; margin-top: 14px; font-size: 17px; }
.feedback.ok { color: var(--color-know); }
.feedback.no { color: var(--color-dontknow); }

.text-input {
  width: 100%;
  font-size: var(--text-xl);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  border: 2px solid var(--color-border);
  margin: var(--space-4) 0;
  text-align: center;
}
.text-input:focus { outline: none; border-color: var(--color-primary); }

/* LCWC */
.lcwc-phase { animation: fadein .18s ease; }
.cover-box {
  background: var(--color-card);
  border: 1px solid rgba(0,0,0,.045);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 50px 20px;
  text-align: center;
  margin: 18px 0;
}
.cover-emoji { font-size: 48px; margin: 0 0 10px; }

/* 쓰기 반복(5회) 도트 인디케이터 - 채워질 때 살짝 커지며 "펑" 하고 채워지는 느낌 */
.write-dots { display: flex; justify-content: center; gap: var(--space-2); margin-top: 18px; }
.write-dot {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-border);
  transform: scale(1);
  opacity: .7;
  transition: transform .22s cubic-bezier(.34,1.56,.64,1), background-color .22s ease, opacity .22s ease;
}
.write-dot.filled {
  background: var(--color-primary);
  opacity: 1;
  transform: scale(1.25);
}

/* LCWC "가리기" 단계: 전체화면 몰입 모드 (상단바/스텝인디케이터 숨김 + 어두운 배경) */
#app.immersive #topbar,
#app.immersive #step-indicator,
#app.immersive #session-timer {
  display: none;
}
#screen-lcwc.immersive-cover .step-caption,
#screen-lcwc.immersive-cover > .progress-bar,
#screen-lcwc.immersive-cover #lcwc-round-text {
  display: none;
}
#screen-lcwc.immersive-cover #lcwc-phase-cover {
  position: fixed;
  inset: 0;
  z-index: 50;
  background: var(--color-text);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  padding: var(--space-6) var(--space-5) calc(var(--space-6) + var(--safe-bottom));
}
#screen-lcwc.immersive-cover .cover-box {
  background: transparent;
  border: none;
  box-shadow: none;
  padding: 0;
  margin: 0;
}
#screen-lcwc.immersive-cover .cover-emoji { font-size: 64px; }
#screen-lcwc.immersive-cover .prompt-text-lg { color: var(--color-card); }
#screen-lcwc.immersive-cover .write-dots { margin-top: 26px; gap: var(--space-3); }
#screen-lcwc.immersive-cover .write-dot { width: 22px; height: 22px; background: rgba(255,255,255,.35); }
#screen-lcwc.immersive-cover .write-dot.filled { background: var(--color-accent); }
#screen-lcwc.immersive-cover #btn-lcwc-check { width: 100%; max-width: 420px; }

.nav-row { display:flex; gap: var(--space-3); margin-top: var(--space-4); }
.nav-row .btn { flex: 1; }

/* 요약 */
.summary-card {
  background: var(--color-card);
  border: 1px solid rgba(0,0,0,.045);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 34px 24px;
  text-align: center;
  margin-top: 10px;
}
.summary-emoji { font-size: 52px; margin: 0; }
.summary-stats { display:flex; gap: var(--space-4); margin: 20px 0; }
.stat-box { flex:1; background: #F4F1EA; border-radius: var(--radius-md); padding: 18px 8px; }
.stat-num { display:block; font-size: 28px; font-weight: 800; color: var(--color-primary-dark); }
.stat-label { font-size: 13px; color: var(--color-text-muted); }

/* 오답노트 */
.word-list { display:flex; flex-direction:column; gap: 10px; margin-top: 12px; }
.word-list-item {
  background: var(--color-card);
  border: 1px solid rgba(0,0,0,.045);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  padding: 14px 18px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.word-list-item .w { font-weight: 800; color: var(--color-primary-dark); font-size: 18px; }
.word-list-item .m { color: var(--color-text-muted); font-size: var(--text-sm); }
.word-list-item .streak { font-size: 13px; color: var(--color-accent); font-weight: 700; }

/* 설정 */
.settings-block {
  background: var(--color-card);
  border: 1px solid rgba(0,0,0,.045);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 18px 20px;
  margin-bottom: var(--space-4);
}
.settings-block h3 { margin: 0 0 var(--space-2); font-size: 17px; }
.settings-block .btn { margin-top: 10px; width: 100%; }

/* "왜 이렇게 공부해요?" 안내 카드 뷰어 (홈 화면 위 모달 오버레이) */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(46, 42, 38, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-4);
  z-index: 200;
}
.modal-overlay[hidden] { display: none; }

.about-learning-panel {
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  width: 100%;
  max-width: 460px;
  max-height: calc(100% - var(--safe-top) - var(--safe-bottom));
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  padding: var(--space-4) var(--space-4) calc(var(--space-4) + var(--safe-bottom));
  animation: fadein .18s ease;
}

.about-learning-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-2);
}
.about-learning-counter { font-size: var(--text-sm); font-weight: 700; color: var(--color-text-muted); }
.about-learning-close {
  background: var(--color-border);
  color: var(--color-text);
  width: 36px;
  height: 36px;
  font-size: 20px;
}
.about-learning-close:active { background: #DDD5C6; }

.about-learning-card { min-height: 260px; padding: 36px 22px; }
.about-learning-emoji { font-size: 44px; margin: 0; }
.about-learning-title { font-size: var(--text-lg); font-weight: 800; color: var(--color-primary-dark); margin: 0; line-height: 1.4; }
.about-learning-body { font-size: var(--text-base); color: var(--color-text); line-height: 1.6; margin: 0; }

.about-learning-dots { display: flex; justify-content: center; gap: 7px; margin: var(--space-3) 0; }
.about-learning-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--color-border); transition: all .15s ease; }
.about-learning-dot.current { background: var(--color-primary); width: 20px; border-radius: 999px; }

.toast {
  position: fixed;
  left: 50%;
  bottom: calc(24px + var(--safe-bottom));
  transform: translateX(-50%);
  background: #2E2A26;
  color: white;
  padding: 12px 20px;
  border-radius: 999px;
  font-size: var(--text-sm);
  z-index: 100;
  box-shadow: 0 6px 20px rgba(0,0,0,0.2);
}

@media (min-width: 600px) {
  .flash-word { font-size: 48px; }
  .quiz-question { font-size: 34px; }
}