:root {
  color-scheme: light;
  --bg: #f3f1eb;
  --card: #fffefa;
  --ink: #242b2a;
  --muted: #68716e;
  --line: #d8d8d0;
  --accent: #176b5b;
  --accent-dark: #105044;
  --accent-soft: #e2f0ec;
  --error: #b4232f;
  --error-soft: #fde8e8;
  --added: #855600;
  --added-soft: #fff1c8;
  --ok: #28704e;
  --shadow: 0 8px 28px rgba(28, 45, 40, .07);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", "DejaVu Sans", sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
}

button, input, select, textarea { font: inherit; }
button, select, input[type="file"], label { touch-action: manipulation; }

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  padding: 1.4rem max(1.2rem, calc((100vw - 1180px) / 2));
  background: #173e37;
  color: white;
}

h1, h2, p { margin-top: 0; }
h1 { margin-bottom: .25rem; font-size: clamp(1.45rem, 3vw, 2.1rem); }
h2 { margin-bottom: .8rem; font-size: 1.05rem; }
.eyebrow { margin-bottom: .25rem; color: #b8d9d1; font-size: .78rem; letter-spacing: .08em; text-transform: uppercase; }
.muted { color: var(--muted); }
.topbar .muted { margin: 0; color: #cbdad6; }

main { width: min(1180px, calc(100% - 2rem)); margin: 1.2rem auto 3rem; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 12px; box-shadow: var(--shadow); }

.message { display: none; margin-bottom: 1rem; padding: .8rem 1rem; border-radius: 8px; }
.message.show { display: block; }
.message.error { color: var(--error); background: var(--error-soft); border: 1px solid #f2b8be; }
.message.success { color: var(--ok); background: #e7f5ed; border: 1px solid #b9dfca; }

.controls { padding: 1rem 1.1rem; margin-bottom: 1rem; }
.control-group { display: flex; align-items: center; gap: .8rem; }
.control-label { color: var(--muted); font-size: .79rem; font-weight: 700; letter-spacing: .04em; text-transform: uppercase; }
.segmented { display: flex; flex-wrap: wrap; gap: .35rem; }
.segmented button { border: 1px solid var(--line); border-radius: 999px; background: white; padding: .5rem .8rem; cursor: pointer; }
.segmented button.active { color: white; background: var(--accent); border-color: var(--accent); }

.settings-grid { display: grid; grid-template-columns: 1.5fr repeat(4, minmax(120px, 1fr)); gap: .8rem; margin-top: 1rem; }
.settings-grid label, .option-grid label { display: flex; flex-direction: column; gap: .32rem; color: var(--muted); font-size: .82rem; }
select, input[type="number"], input[type="text"] { width: 100%; min-height: 38px; border: 1px solid var(--line); border-radius: 6px; background: white; color: var(--ink); padding: .42rem .55rem; }
details { margin-top: .9rem; border-top: 1px solid var(--line); padding-top: .7rem; }
summary { color: var(--accent-dark); cursor: pointer; font-size: .88rem; }
.option-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: .7rem 1rem; margin-top: .8rem; }
.option-grid label:has(input[type="checkbox"]) { flex-direction: row; align-items: center; }

.workspace { padding: 1rem; }
.workspace-head { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: .75rem; }
.badge { display: inline-block; padding: .25rem .55rem; border-radius: 999px; color: var(--accent-dark); background: var(--accent-soft); font-size: .78rem; font-weight: 700; }
.badge.subtle { color: var(--muted); background: #eeeeda; }
.cue-panel { margin-bottom: .8rem; padding: .75rem 1rem; background: #eef3f1; border-left: 4px solid var(--accent); border-radius: 4px; }
.cue-panel p { margin: .35rem 0 0; white-space: pre-wrap; font-family: "Noto Sans Mono", "DejaVu Sans Mono", ui-monospace, monospace; }
.first-letter-panel { max-height: 220px; overflow: auto; background: #f7f4e8; border-left-color: #9a742b; }
.first-letter-panel pre { margin: .35rem 0 0; white-space: pre-wrap; overflow-wrap: anywhere; font: 14px/1.55 "Noto Sans Mono", "DejaVu Sans Mono", ui-monospace, monospace; }

.editor-shell { position: relative; min-height: 410px; border: 1px solid #b9c1be; border-radius: 8px; overflow: hidden; background: white; }
#answerEditor, .live-overlay {
  width: 100%; min-height: 410px; margin: 0; padding: 1rem; border: 0;
  white-space: pre-wrap; overflow-wrap: break-word; tab-size: 4;
  font: 16px/1.62 "Noto Sans Mono", "DejaVu Sans Mono", Consolas, monospace;
}
#answerEditor { display: block; resize: vertical; color: var(--ink); background: white; outline: none; }
#answerEditor:focus { box-shadow: inset 0 0 0 2px rgba(23, 107, 91, .25); }
#answerEditor:disabled { background: #f6f6f2; }
.live-overlay { display: none; position: absolute; inset: 0; pointer-events: none; overflow: auto; color: var(--ink); background: white; }
.editor-shell.live #answerEditor { position: relative; z-index: 2; color: transparent; caret-color: var(--ink); background: transparent; -webkit-text-fill-color: transparent; }
.editor-shell.live #answerEditor::selection { background: rgba(23, 107, 91, .23); }
.editor-shell.live .live-overlay { display: block; z-index: 1; }
.live-overlay .wrong { color: var(--error); background: var(--error-soft); text-decoration: underline; text-decoration-thickness: 2px; }

.neutral-stats { min-height: 1.6rem; padding-top: .45rem; font-size: .82rem; text-align: right; }
.actions { display: flex; flex-wrap: wrap; gap: .6rem; margin-top: .65rem; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 39px; border: 1px solid #aeb5b2; border-radius: 7px; color: var(--ink); background: white; padding: .48rem .85rem; cursor: pointer; text-decoration: none; }
.button:hover:not(:disabled) { border-color: var(--accent); }
.button.primary { color: white; background: var(--accent); border-color: var(--accent); }
.button.primary:hover:not(:disabled) { background: var(--accent-dark); }
.button:disabled { opacity: .5; cursor: not-allowed; }
#fileInput { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.shortcut-help { margin: .65rem 0 0; color: var(--muted); font-size: .76rem; }

.results-grid { display: grid; grid-template-columns: 2fr 1fr; gap: 1rem; margin-top: 1rem; }
.results-grid > * { min-width: 0; padding: 1rem; }
.score-summary { margin-bottom: .8rem; }
.metric-row { display: grid; grid-template-columns: repeat(4, minmax(90px, 1fr)); gap: .5rem; }
.metric { padding: .55rem; background: #f2f3ef; border-radius: 6px; }
.metric strong { display: block; font-size: 1.2rem; }
.metric span { color: var(--muted); font-size: .73rem; }
.diff-view { max-height: 470px; overflow: auto; white-space: pre-wrap; overflow-wrap: anywhere; font: 14px/1.65 "Noto Sans Mono", "DejaVu Sans Mono", monospace; }
.diff-correct { color: var(--ink); }
.diff-omit { color: var(--error); background: var(--error-soft); text-decoration: underline wavy; }
.diff-add { color: var(--added); background: var(--added-soft); text-decoration: line-through; }
.diff-sub { color: var(--error); background: var(--error-soft); }
.diff-legend { display: flex; flex-wrap: wrap; gap: .8rem; margin-bottom: .6rem; color: var(--muted); font: 12px/1.4 sans-serif; }
.turn-review { margin-top: 1rem; }
.turn-item { display: flex; justify-content: space-between; gap: 1rem; padding: .4rem .55rem; border-top: 1px solid var(--line); font-size: .83rem; }
.turn-item.perfect { color: var(--ok); }
.turn-item.missed { color: var(--error); }
.progress-summary dl { display: grid; grid-template-columns: 1fr auto; gap: .45rem 1rem; margin: 0; }
.progress-label { display: flex; justify-content: space-between; margin-bottom: .3rem; color: var(--muted); font-size: .8rem; }
progress { width: 100%; height: .65rem; margin-bottom: 1rem; accent-color: var(--accent); }
.progress-summary dt { color: var(--muted); }
.progress-summary dd { margin: 0; font-weight: 650; text-align: right; }
.problem-list { margin: .8rem 0 0; padding-left: 1.2rem; font-size: .84rem; }
.problem-sentence-heading { margin: 1rem 0 .45rem; }
.problem-sentence-list { display: grid; gap: .55rem; margin: 0; padding: 0; list-style: none; }
.problem-sentence-list li { display: grid; grid-template-columns: auto 1fr; align-items: start; gap: .55rem; padding: .6rem; border-radius: 7px; background: #f5f1e8; font-size: .84rem; }
.problem-sentence-list strong { min-width: 4.5rem; color: var(--error); font-size: .76rem; }
.mobile-only { display: none; }
#knewItButton[hidden] { display: none !important; }
.hidden { display: none !important; }

@media (max-width: 800px) {
  .topbar { align-items: flex-start; }
  .settings-grid, .option-grid { grid-template-columns: 1fr 1fr; }
  .results-grid { grid-template-columns: 1fr; }
  .metric-row { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 520px) {
  main { width: min(100% - 1rem, 1180px); }
  .topbar { gap: 1rem; padding-inline: .8rem; }
  .settings-grid, .option-grid { grid-template-columns: 1fr; }
  .control-group { align-items: flex-start; flex-direction: column; }
  .workspace-head { align-items: flex-start; flex-direction: column; }
  #answerEditor, .live-overlay, .editor-shell { min-height: 330px; }
}

/* JavaScript adds this class only for mobile browsers or compact touch devices. */
.mobile-ui { -webkit-text-size-adjust: 100%; }

.mobile-ui body {
  padding-bottom: env(safe-area-inset-bottom, 0);
  overscroll-behavior-y: none;
}

.mobile-ui .topbar {
  align-items: center;
  flex-wrap: wrap;
  gap: .65rem;
  padding: calc(.7rem + env(safe-area-inset-top, 0)) .75rem .7rem;
}
.mobile-ui .topbar > div:first-child { min-width: 0; }
.mobile-ui .eyebrow { display: none; }
.mobile-ui h1 { margin-bottom: .15rem; font-size: 1.28rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.mobile-ui .topbar .muted { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: .72rem; }
.mobile-ui .load-area {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  flex: 1 0 100%;
  gap: .45rem;
}
.mobile-ui #recentDialogueSelect { min-width: 0; min-height: 44px; color: var(--ink); background: white; }
.mobile-ui .load-area .button { min-height: 44px; padding-inline: .75rem; }

.mobile-ui main {
  display: flex;
  flex-direction: column;
  width: calc(100% - .75rem);
  margin: .45rem auto calc(1rem + env(safe-area-inset-bottom, 0));
}
.mobile-ui main > .message { order: 0; }
.mobile-ui main > .workspace { order: 1; }
.mobile-ui main > .controls { order: 2; margin-top: .45rem; margin-bottom: 0; }
.mobile-ui main > .results-grid { order: 3; }
.mobile-ui .card { border-radius: 10px; box-shadow: 0 3px 14px rgba(28, 45, 40, .06); }
.mobile-ui .message { margin-bottom: .45rem; }
.mobile-ui .controls { margin-bottom: .45rem; padding: .7rem; }
.mobile-ui .mobile-collapsible.mobile-collapsed > .mobile-collapse-content { display: none; }
.mobile-ui .mobile-accordion-toggle {
  width: 100%;
  min-height: 46px;
  align-items: center;
  justify-content: space-between;
  border: 0;
  color: var(--accent-dark);
  background: transparent;
  padding: .2rem .15rem;
  font-weight: 750;
  text-align: left;
}
.mobile-ui .mobile-accordion-toggle span:last-child { font-size: 1.25rem; transition: transform .18s ease; }
.mobile-ui .mobile-collapsible:not(.mobile-collapsed) > .mobile-accordion-toggle span:last-child { transform: rotate(180deg); }
.mobile-ui .mobile-collapse-content > h2:first-child { display: none; }
.mobile-ui .control-group { display: block; }
.mobile-ui .mode-group > .control-label { display: block; margin-bottom: .4rem; }
.mobile-ui .segmented { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .3rem; }
.mobile-ui .segmented button { min-height: 44px; padding: .4rem .25rem; border-radius: 8px; font-size: .78rem; line-height: 1.2; }

.mobile-ui .settings-grid { grid-template-columns: 1fr 1fr; gap: .6rem; margin-top: .7rem; }
.mobile-ui .settings-grid > label:first-child,
.mobile-ui #seedWrap,
.mobile-ui #mobileBlankDifficultyWrap { grid-column: 1 / -1; }
.mobile-ui .settings-grid label,
.mobile-ui .option-grid label { font-size: .78rem; }
.mobile-ui select,
.mobile-ui input[type="number"],
.mobile-ui input[type="text"] { min-height: 44px; font-size: 16px; }
.mobile-ui details { margin-top: .65rem; padding-top: .35rem; }
.mobile-ui summary { display: flex; align-items: center; min-height: 44px; }
.mobile-ui .option-grid { grid-template-columns: 1fr; gap: .15rem; margin-top: .35rem; }
.mobile-ui .option-grid label:has(input[type="checkbox"]) { min-height: 44px; }
.mobile-ui input[type="checkbox"] { width: 21px; height: 21px; margin-right: .35rem; }
.mobile-ui .mobile-blank-difficulty {
  flex-direction: column;
  gap: .35rem;
  color: var(--muted);
  font-size: .78rem;
}
.mobile-ui .difficulty-stepper { display: grid; grid-template-columns: 48px 1fr 48px; gap: .4rem; }
.mobile-ui .difficulty-stepper button {
  min-height: 46px;
  border: 1px solid var(--line);
  border-radius: 7px;
  color: var(--accent-dark);
  background: white;
  font-size: 1.35rem;
  font-weight: 700;
}
.mobile-ui .difficulty-stepper button:disabled { opacity: .4; }
.mobile-ui .difficulty-stepper output {
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 7px;
  color: var(--accent-dark);
  background: var(--accent-soft);
  font-size: 1rem;
  font-weight: 750;
}
.mobile-ui .mobile-settings-actions {
  grid-template-columns: 1fr 1fr;
  gap: .45rem;
  margin-top: .7rem;
}
.mobile-ui .mobile-settings-actions .button { min-height: 46px; }

.mobile-ui .workspace { padding: .65rem; }
.mobile-ui .workspace-head { align-items: flex-start; flex-direction: column; gap: .35rem; margin-bottom: .55rem; }
.mobile-ui #positionInfo { font-size: .75rem; }
.mobile-ui .cue-panel { max-height: 180px; overflow: auto; padding: .6rem .7rem; }
.mobile-ui .editor-shell,
.mobile-ui #answerEditor,
.mobile-ui .live-overlay {
  height: clamp(300px, 52dvh, 560px);
  min-height: 300px;
}
.mobile-ui #answerEditor,
.mobile-ui .live-overlay { padding: .75rem; font-size: 16px; line-height: 1.55; }
.mobile-ui #answerEditor { resize: none; }
.mobile-ui .neutral-stats { padding-top: .35rem; font-size: .74rem; }

.mobile-ui .actions {
  position: sticky;
  z-index: 10;
  bottom: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: .45rem;
  margin: .45rem -.65rem -.65rem;
  padding: .6rem .65rem calc(.6rem + env(safe-area-inset-bottom, 0));
  border-top: 1px solid var(--line);
  border-radius: 0 0 10px 10px;
  background: rgba(255, 254, 250, .96);
  box-shadow: 0 -5px 16px rgba(28, 45, 40, .08);
  backdrop-filter: blur(8px);
}
.mobile-ui .actions .button { min-height: 46px; padding: .5rem .45rem; }
.mobile-ui .mobile-only:not(.hidden) { display: inline-flex; }
.mobile-ui .mobile-settings-actions.mobile-only:not(.hidden) { display: grid; }
.mobile-ui.mobile-blank-reveal #checkButton { display: none; }
.mobile-ui .self-grade-button { font-weight: 700; }
.mobile-ui #missedItButton:not(:disabled) { color: var(--error); border-color: #e4a5aa; background: #fff1f1; }
.mobile-ui #resetButton,
.mobile-ui #newRoundButton { display: none; }
.mobile-ui #hintButton:disabled { display: none; }
.mobile-ui #retryTurnsButton { grid-column: 1 / -1; }
.mobile-ui .shortcut-help { display: none; }

.mobile-ui .results-grid { grid-template-columns: 1fr; gap: .45rem; margin-top: .45rem; }
.mobile-ui .results-grid > * { padding: .75rem; }
.mobile-ui .metric-row { grid-template-columns: 1fr 1fr; }
.mobile-ui .diff-view { max-height: 55dvh; }
.mobile-ui .turn-item { min-height: 44px; align-items: center; }
.mobile-ui #answerEditor.reveal-highlight::selection { color: var(--ink); background: #f5d56f; -webkit-text-fill-color: var(--ink); }
.mobile-ui .editor-shell.reveal-flash { box-shadow: 0 0 0 3px rgba(213, 166, 35, .28); }