:root{
  --bg: #ffffff;
  --surface: #ffffff;
  --surface-raised: #f7f7f7;
  --surface-raised-2: #ededed;
  --ink: #111111;
  --ink-dim: #555555;
  --ink-faint: #777777;
  --accent: #000000;
  --accent-ink: #000000;
  --correct: #111111;
  --wrong: #111111;
  --border: #dddddd;
}
:root[data-theme="light"]{
  --bg: #ffffff;
  --surface: #ffffff;
  --surface-raised: #f7f7f7;
  --surface-raised-2: #ededed;
  --ink: #111111;
  --ink-dim: #555555;
  --ink-faint: #777777;
  --accent: #000000;
  --accent-ink: #000000;
  --correct: #111111;
  --wrong: #111111;
  --border: #dddddd;
}
:root[data-theme="dark"]{
  --bg: #111111;
  --surface: #1a1a1a;
  --surface-raised: #262626;
  --surface-raised-2: #2e2e2e;
  --ink: #f8f8f8;
  --ink-dim: #b8b8b8;
  --ink-faint: #8f8f8f;
  --accent: #f8f8f8;
  --accent-ink: #111111;
  --correct: #f8f8f8;
  --wrong: #f8f8f8;
  --border: #2f2f2f;
}

*, *::before, *::after{ box-sizing:border-box; }
html{ min-height:100%; background: var(--bg); }
body{
  margin:0;
  min-height:100vh;
  color: var(--ink);
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  display:flex;
  justify-content:center;
  padding: 32px 18px;
  background: var(--bg);
}

body::before{
  content:'';
  position:fixed;
  inset:0;
  z-index:-2;
  background: none;
}

.app{
  width:100%;
  max-width:700px;
}

.screen{ display:none; }
.screen.active{ display:block; }

.site-header{
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
  align-items:center;
  gap:18px;
  margin-bottom: 28px;
}
.brand{ display:flex; flex-direction:column; gap:6px; }
.header-tools{
  display:flex;
  flex-wrap:nowrap;
  align-items:center;
  gap:10px;
}
.brand-label{
  font-size: 12px;
  color: var(--ink-dim);
  letter-spacing: 0.22em;
  text-transform: uppercase;
}
.brand-title{
  font-size: 22px;
  font-weight:700;
}
.site-nav{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
}
.nav-link{
  appearance:none;
  border: 4px solid transparent;
  background: transparent;
  color: var(--ink-dim);
  font-family: inherit;
  font-weight:700;
  font-size:13px;
  padding: 12px 16px;
  cursor:pointer;
  transition: background .15s ease, color .15s ease, border-color .15s ease;
}
.nav-link.active,
.nav-link:hover{
  color: var(--ink);
  background: rgba(0, 0, 0, 0.06);
  border-color: var(--ink);
}
.theme-toggle{
  appearance:none;
  border: 4px solid transparent;
  background: transparent;
  color: var(--ink-dim);
  font-family: inherit;
  font-weight:700;
  font-size:0;
  padding: 12px 16px;
  cursor:pointer;
  transition: background .15s ease, color .15s ease, border-color .15s ease;
}
.theme-icon{
  display:inline-flex;
  font-size:18px;
  line-height:1;
}
.theme-toggle:hover{
  color: var(--ink);
  background: rgba(0, 0, 0, 0.06);
  border-color: var(--ink);
}

.site-home,
.page-panel,
.home,
.word-card,
.detail-panel{
  background: var(--surface);
  border: 1px solid var(--border);
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
}

.site-home,
.page-panel{
  padding: 40px 34px;
}
.site-home{
  display:flex;
  flex-direction:column;
  gap:26px;
}
.profile-home{ align-items:center; }
.profile-avatar{
  width:96px;
  height:96px;
  object-fit:cover;
  border: 1px solid var(--border);
  box-shadow: 0 8px 20px rgba(0,0,0,0.06);
  background: var(--surface);
}
.profile-handle{
  font-size:13px;
  color: var(--ink-dim);
  margin-bottom:14px;
  letter-spacing: 0.16em;
}
.hero-title{
  font-size: clamp(34px, 6vw, 52px);
  font-weight:700;
  margin:0 0 18px;
  letter-spacing: -0.05em;
}
.hero-copy{
  max-width: 520px;
  color: var(--ink-dim);
  line-height:1.8;
  margin:0 auto 26px;
}
.home-actions{
  display:flex;
  flex-wrap:wrap;
  gap:14px;
  justify-content:center;
}
.home-footnote{
  color: var(--ink-faint);
  font-size: 13px;
  max-width: 520px;
  text-align:center;
  margin-top:16px;
}

.home{
  text-align:center;
  min-height: 70vh;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  padding: 40px 24px;
  gap: 26px;
}
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:6px;
  font-size:14px;
  color: var(--ink-dim);
}
.plus{ color: var(--ink); font-weight:700; }
.title{
  font-size: clamp(32px, 7vw, 46px);
  font-weight:700;
  line-height:1.3;
  margin:0;
  letter-spacing:0.01em;
}
.title .hl{ color: var(--ink); }
.intro-copy{
  max-width: 520px;
  color: var(--ink-dim);
  line-height:1.8;
  margin:0 auto;
}

.cta,
.btn-secondary,
.btn-primary-flat{
  appearance:none;
  border: 1px solid var(--border);
  font-family: inherit;
  font-weight:700;
  cursor:pointer;
  transition: background .15s ease, border-color .15s ease, color .15s ease, transform .08s ease;
  padding: 14px 26px;
  font-size: 14px;
  min-width: 140px;
  text-align:center;
  background: var(--surface-raised);
  color: var(--ink);
}
.cta{
  background: var(--surface);
  color: var(--ink);
}
.cta:hover,
.btn-secondary:hover,
.btn-primary-flat:hover{
  transform: translateY(-1px);
  background: var(--surface-raised-2);
  border-color: var(--ink);
}

.page-panel{
  padding: 40px 34px;
}
.section-title{
  font-size: clamp(26px, 4vw, 36px);
  margin:0 0 18px;
}
.section-text{
  margin:0 0 28px;
  color: var(--ink-dim);
  line-height:1.9;
}
.feature-grid{
  display:grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap:20px;
}
.feature-card{
  background: var(--surface-raised);
  border: 1px solid var(--border);
  padding: 28px 22px;
  min-height: 170px;
  display:flex;
  flex-direction:column;
  justify-content:space-between;
}
.feature-card:not(.placeholder){
  cursor: pointer;
}
.feature-card:not(.placeholder):hover,
.feature-card:not(.placeholder):focus-visible{
  transform: translateY(-1px);
  border-color: var(--ink);
  background: var(--surface);
}
.feature-card:not(.placeholder):focus-visible{ outline: none; box-shadow: 0 0 0 3px rgba(0,0,0,0.08); }
.feature-card h3{ margin:0 0 12px; font-size:16px; color: var(--ink); }
.feature-card p{ margin:0; color: var(--ink-dim); line-height:1.7; font-size:13px; }
.feature-card.placeholder{
  background: var(--surface);
  cursor: default;
}
.feature-card.placeholder h3{ color: var(--ink-dim); }

.note-list{
  display:flex;
  flex-direction:column;
  gap:14px;
}
.note-pagination{
  display:flex;
  justify-content:center;
  align-items:center;
  gap:12px;
  margin-top:24px;
}
.pagination-btn{
  padding: 10px 16px;
  border: 1px solid var(--border);
  background: var(--surface-raised);
  color: var(--ink);
  cursor: pointer;
  border-radius: 8px;
}
.pagination-btn:disabled{
  opacity: 0.5;
  cursor: default;
}
.post-card{
  background: var(--surface-raised);
  border: 1px solid transparent;
  padding: 18px 20px;
  cursor:pointer;
}
.post-card:hover,
.post-card:focus-visible{
  border-color: var(--ink);
  background: var(--surface);
}
.post-row{
  display:grid;
  grid-template-columns: 1fr 3fr 3fr;
  gap:16px;
  align-items:center;
}
.post-label{
  display:flex;
  align-items:center;
  gap:10px;
}
.post-number,
.post-text{
  display:block;
  font-size:14px;
  color: var(--ink);
}
.post-number{
  font-weight:700;
  color: var(--ink-dim);
}
.post-summary-table{
  width:100%;
  border-collapse:collapse;
  margin-top:12px;
}
.post-summary-table th,
.post-summary-table td{
  border:1px solid var(--border);
  padding:10px 12px;
  text-align:left;
  font-size:14px;
}
.post-summary-table th{
  background: var(--surface);
  color: var(--ink);
}
.post-summary-table tbody tr:nth-child(odd){
  background: var(--surface);
}
.post-card:focus-visible{ outline:none; box-shadow: 0 0 0 3px rgba(0,0,0,0.08); }
.post-header{
  display:flex;
  align-items:center;
  gap:14px;
}
.post-number{
  font-size:18px;
  font-weight:700;
  color: var(--ink-faint);
}
.post-title{
  font-size:18px;
  margin:0;
}
.note-modal{
  position: fixed;
  inset:0;
  display:flex;
  align-items:center;
  justify-content:center;
  padding:24px;
  z-index:50;
}
.note-modal.hidden{
  display:none;
}
.note-modal-backdrop{
  position:absolute;
  inset:0;
  background: rgba(0,0,0,0.72);
}
.note-modal-panel{
  position:relative;
  width:100%;
  height:100%;
  max-width:100%;
  max-height:100%;
  overflow-y:auto;
  padding: 28px 24px;
  border: 0;
  background: var(--surface-raised);
  z-index:1;
}
.note-close-btn{
  appearance:none;
  border:none;
  background: transparent;
  color: var(--ink);
  font-size:24px;
  font-weight:700;
  cursor:pointer;
  position:absolute;
  top:18px;
  right:18px;
}
.note-modal-header{
  display:none;
}
.note-modal-body{
  color: var(--ink-dim);
  line-height:1.8;
  display:flex;
  flex-direction:column;
  gap:20px;
}
.post-sentence{
  display:grid;
  grid-template-columns: 40px 1fr auto;
  grid-template-rows: auto auto;
  gap:8px 12px;
  padding:12px 16px;
  border-bottom:1px solid var(--border);
  align-items:center;
}
.sentence-label{
  font-weight:700;
  color: var(--ink-dim);
  margin:0;
  min-width:36px;
  text-align:right;
  grid-row:1 / 2;
  grid-column:1 / 2;
}
.sentence-toggle{
  appearance:none;
  border:1px solid var(--border);
  padding:10px 14px;
  background: var(--surface);
  color: var(--ink);
  font-weight:700;
  cursor:pointer;
  width:max-content;
}
.sentence-answer{
  padding:12px 14px;
  border:1px dashed var(--border);
  background: var(--surface);
  color: var(--ink);
  display:flex;
  flex-direction:column;
  gap:6px;
  grid-column: 1 / -1;
  margin-top:6px;
}
.sentence-answer.hidden{ display:none; }
.answer-sentence{
  font-weight:700;
}
.answer-vocab{
  color: var(--ink-dim);
  font-size:14px;
}
.post-answer{
  padding:16px 18px;
  border:1px dashed var(--border);
  background: var(--surface);
  color: var(--ink);
}
.post-answer.hidden{ display:none; }

.post-source{
  margin-top:12px;
  font-size:13px;
  color: var(--ink-dim);
  text-align:right;
}

.detail-modal{
  position: fixed;
  inset:0;
  display:flex;
  align-items:center;
  justify-content:center;
  padding:24px;
  z-index:50;
}
.detail-modal.hidden{ display:none; }
.detail-modal-backdrop{
  position:absolute;
  inset:0;
  background: rgba(0,0,0,0.72);
}
.detail-panel{
  position:relative;
  width:min(100%, 680px);
  max-height:min(100vh, 92vh);
  overflow-y:auto;
  padding: 28px 24px;
  border: 3px solid var(--border);
  background: var(--surface-raised);
  z-index:1;
}
.detail-header{ margin:0 0 14px; font-size:18px; }
.detail-body{ color: var(--ink-dim); line-height:1.8; }
.detail-body p{ margin:0 0 16px; }
.detail-body ul{ margin: 0 0 16px 18px; }
.detail-body li{ margin-bottom: 10px; }
.detail-actions{
  display:flex;
  flex-wrap:wrap;
  gap:12px;
  margin-top:24px;
}
#detailStartBtn.hidden{ display:none; }

.practice-head{ display:flex; flex-wrap:wrap; align-items:center; justify-content:space-between; gap:14px; margin-bottom:28px; }
.progress-label{ font-size:14px; color: var(--ink-dim); }
.progress-track{ flex:1; display:flex; gap:5px; }
.progress-track .segment{ flex:1; height:16px; background: var(--surface-raised); border:2px solid var(--border); }
.progress-track .segment.filled{ background: var(--ink); }
.progress-track .segment.current{ background: var(--surface-raised-2); box-shadow: inset 0 0 0 2px var(--ink); }
.word-card{ padding:44px 32px; margin-bottom:26px; text-align:center; }
.meaning-text{ font-size: clamp(20px, 4.2vw, 28px); font-weight:700; color: var(--ink); margin-bottom:16px; line-height:1.6; }
.pos-text{ display:inline-block; font-size:12px; color: var(--ink); background: var(--surface-raised); padding:3px 10px; border:1px solid var(--border); margin-bottom:14px; }
.pron-text{ font-size:13px; color: var(--ink-faint); }

.input-wrap{ position:relative; margin-bottom:18px; }
.char-overlay{ display:flex; flex-wrap:wrap; justify-content:center; gap:2px; padding:20px 22px; min-height:30px; font-size:22px; }
.char-overlay .ph{ color: var(--ink-faint); }
.char-overlay .ok{ color: var(--ink); }
.char-overlay .bad{ color: var(--ink); border-bottom:3px solid var(--ink); }
.char-overlay .cursor{ width:11px; height:24px; background: var(--ink); margin-left:1px; animation: blink .8s steps(1) infinite; }
@keyframes blink{ 50%{ opacity:0; } }
#typingInput{ position:absolute; inset:0; width:100%; height:100%; opacity:0; cursor:text; font-size:22px; }

.metric-grid{ display:grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap:16px; margin-bottom:24px; }
.metric-card{ padding:24px 18px; border:3px solid var(--border); text-align:center; box-shadow: 6px 6px 0 0 var(--border); background: var(--surface-raised); }
.metric-card.cpm .metric-value{ color: var(--ink); }
.metric-card.acc .metric-value{ color: var(--ink); }
.metric-value{ font-size:28px; font-weight:700; margin-bottom:8px; }
.result-header,
.result-title{ text-align:center; }
.metric-label{ color: var(--ink-dim); font-size:13px; }

.word-list{ background: var(--surface); border:3px solid var(--border); padding:18px; box-shadow: 6px 6px 0 0 var(--border); }
.word-list-title{ font-size:14px; margin-bottom:12px; color: var(--ink-dim); }
.word-item{ display:grid; grid-template-columns: 24px 1fr auto; align-items:center; gap:10px; padding:14px 0; border-top:1px solid rgba(255,255,255,0.06); }
.word-item:first-child{ border-top:none; }
.word-item.ok .icon{ color: var(--ink); }
.word-item.bad .icon{ color: var(--ink); }
.word-item .icon{ width:24px; text-align:center; }
.word-item .w{ font-weight:700; }
.word-item .m{ color: var(--ink-dim); display:block; font-size:12px; margin-top:2px; }
.word-item .wcpm{ color: var(--ink-faint); font-size:12px; text-align:right; }

.result-actions{ display:flex; gap:14px; flex-wrap:wrap; justify-content:center; margin-top:40px; }

@media (max-width: 560px){
  .feature-grid{ grid-template-columns: 1fr; }
  .home{ padding: 28px 20px; }
  .page-panel{ padding: 30px 24px; }
  .practice-head{ flex-direction:column; align-items:flex-start; }
  .metric-grid{ grid-template-columns: 1fr; }
}