/* components/lesson-player.css — hộp học bài (static/js/lesson_player.js), phong cách C.
   Viết lại 19/09/2026: khung phẳng, thanh tiến độ + số bước ở trên, chân hộp cố định (phản hồi bên trái,
   nút Lùi + nút chính CÓ CHỮ bên phải) thay cho 2 nút tròn nổi hai bên; bỏ emoji và khối quảng cáo cũ.
   Mọi quy tắc nằm dưới #lesson-overlay để không đè lên trang chứa (dashboard cũ cũng nạp file này).
   Màu: chỉ biến trong tokens.css (có giá trị dự phòng cho trang cũ). */

/* ── Khung ─────────────────────────────────────────────────────────── */
#lesson-overlay[hidden] { display: none !important; }
#lesson-overlay {
  position: fixed; inset: 0; z-index: 9999;
  display: none; align-items: center; justify-content: center;
  padding: 24px;
  background: rgba(15, 23, 42, 0.45);
  opacity: 0; transition: opacity 0.2s ease;
  font-family: var(--font, Inter, system-ui, sans-serif);
  color: var(--text, #37424d);
}
#lesson-overlay.active { opacity: 1; }
body.learning-mode { overflow: hidden; }

#lesson-overlay .lesson-window {
  width: 100%; max-width: 760px; height: min(860px, 100%);
  display: flex; flex-direction: column;
  background: var(--bg, #fff);
  border-radius: 16px;
  box-shadow: var(--shadow-pop, 0 8px 28px rgba(15, 23, 42, 0.14));
  overflow: hidden;
  transform: translateY(8px); transition: transform 0.2s ease;
}
#lesson-overlay.active .lesson-window { transform: none; }
#lesson-overlay .lesson-main { flex: 1; min-height: 0; display: flex; flex-direction: column; }

/* Thanh trên: nút đóng · tiến độ · số bước */
#lesson-overlay .lesson-header {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 20px; border-bottom: 1px solid var(--line, #e9edf1);
}
#lesson-overlay .close-lesson {
  flex-shrink: 0; width: 34px; height: 34px; display: grid; place-items: center;
  border: 0; border-radius: var(--r, 6px); background: none; cursor: pointer;
  color: var(--muted, #6b7785); font-size: 18px; line-height: 1;
}
#lesson-overlay .close-lesson:hover { background: var(--bg-soft, #f3f5f7); color: var(--ink, #1f2933); }
#lesson-overlay .progress-container {
  flex: 1; height: 6px; border-radius: 999px; overflow: hidden; background: var(--bg-soft, #f3f5f7);
}
#lesson-overlay #lesson-progress-bar {
  height: 100%; width: 0; border-radius: 999px; background: var(--accent, #0576a6);
  transition: width 0.35s ease;
}
#lesson-overlay .lesson-counter {
  flex-shrink: 0; min-width: 40px; text-align: right;
  font-size: 13px; font-weight: 600; color: var(--muted, #6b7785); font-variant-numeric: tabular-nums;
}

/* Thân: cuộn được, nội dung giữa, rộng tối đa 560px */
#lesson-overlay #lesson-body { flex: 1; min-height: 0; overflow-y: auto; }
#lesson-overlay #lesson-content {
  min-height: 100%; max-width: 600px; margin: 0 auto; padding: 32px 24px 40px;
  display: flex; flex-direction: column;
}
#lesson-overlay #lesson-content.is-intro { justify-content: center; }

/* Chân hộp: phản hồi + nút */
#lesson-overlay .lesson-footer {
  flex-shrink: 0; display: flex; align-items: center; gap: 16px;
  padding: 14px 20px; border-top: 1px solid var(--line, #e9edf1); background: var(--bg, #fff);
}
#lesson-overlay #feedback-msg { flex: 1; min-width: 0; }
#lesson-overlay .lesson-nav { display: flex; gap: 8px; flex-shrink: 0; margin-left: auto; }
#lesson-overlay .lesson-nav-btn {
  height: 44px; border-radius: var(--r-md, 8px); cursor: pointer;
  font: inherit; font-size: 15px; font-weight: 600; line-height: 1;
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}
#lesson-overlay .lesson-nav-left {
  width: 44px; border: 1px solid var(--line, #e9edf1); background: var(--bg, #fff); color: var(--text, #37424d);
}
#lesson-overlay .lesson-nav-left:hover:not(:disabled) { border-color: var(--faint, #a0aab4); color: var(--ink, #1f2933); }
#lesson-overlay .lesson-nav-left:disabled { opacity: 0.4; cursor: default; }
#lesson-overlay .lesson-nav-right {
  min-width: 150px; padding: 0 24px;
  border: 1px solid var(--accent, #0576a6); background: var(--accent, #0576a6); color: var(--on-accent, #fff);
}
#lesson-overlay .lesson-nav-right:hover:not(:disabled) { background: var(--accent-hover, #045e87); border-color: var(--accent-hover, #045e87); }
#lesson-overlay .lesson-nav-right:disabled {
  background: var(--bg-soft, #f3f5f7); border-color: var(--line, #e9edf1); color: var(--faint, #a0aab4); cursor: default;
}

/* Dòng phản hồi (JS: _lpFeedback) */
#lesson-overlay .lp-fb { display: flex; align-items: flex-start; gap: 10px; animation: lp-rise 0.2s ease; }
#lesson-overlay .lp-fb-icon {
  flex-shrink: 0; width: 28px; height: 28px; border-radius: 50%; display: grid; place-items: center;
}
#lesson-overlay .lp-fb-text { display: flex; flex-direction: column; gap: 2px; min-width: 0; font-size: 14px; line-height: 1.45; }
#lesson-overlay .lp-fb-text b { font-size: 15px; }
#lesson-overlay .lp-fb-text span { color: var(--muted, #6b7785); }
#lesson-overlay .lp-fb.is-ok .lp-fb-icon { background: var(--green-bg, #e8f3ec); color: var(--green, #2b6f4a); }
#lesson-overlay .lp-fb.is-ok b { color: var(--green, #2b6f4a); }
#lesson-overlay .lp-fb.is-bad .lp-fb-icon { background: var(--red-bg, #fbe9e7); color: var(--red, #a33a2c); }
#lesson-overlay .lp-fb.is-bad b { color: var(--red, #a33a2c); }
#lesson-overlay .lp-fb.is-warn .lp-fb-icon { background: var(--amber-bg, #fbefdf); color: var(--amber, #9a5b13); }
#lesson-overlay .lp-fb.is-warn b { color: var(--amber, #9a5b13); font-weight: 600; }

/* ── Màn "Phần tiếp theo" / "Chúc mừng" ───────────────────────────── */
#lesson-overlay .lesson-intro { display: flex; flex-direction: column; align-items: center; text-align: center; gap: 4px; }
#lesson-overlay .lesson-intro-icon {
  width: 64px; height: 64px; margin-bottom: 14px; border-radius: 18px; display: grid; place-items: center;
  background: var(--accent-soft, #e3f3fa); color: var(--accent, #0576a6);
}
#lesson-overlay .lesson-intro-icon-done { background: var(--green-tag, #e3f1e8); color: var(--green, #2b6f4a); }
#lesson-overlay .lesson-intro-title { margin: 0; font-size: 24px; font-weight: 700; color: var(--ink, #1f2933); letter-spacing: -0.01em; }
#lesson-overlay .lesson-intro-sub { margin: 6px 0 0; font-size: 15px; color: var(--muted, #6b7785); max-width: 400px; line-height: 1.5; }
#lesson-overlay .lesson-intro-score {
  margin-top: 20px; padding: 12px 24px; border-radius: var(--r-md, 8px); background: var(--bg-soft, #f3f5f7);
  display: flex; align-items: baseline; gap: 8px; font-size: 14px; color: var(--muted, #6b7785);
}
#lesson-overlay .lesson-intro-score b { font-size: 26px; color: var(--ink, #1f2933); font-variant-numeric: tabular-nums; }

/* ── Thẻ từ vựng / ngữ pháp ───────────────────────────────────────── */
#lesson-overlay .card-learning { display: flex; flex-direction: column; gap: 20px; }
#lesson-overlay .lp-kicker {
  align-self: center; padding: 3px 10px; border-radius: 999px;
  background: var(--accent-soft, #e3f3fa); color: var(--accent, #0576a6);
  font-size: 12px; font-weight: 600; letter-spacing: 0.02em;
}
#lesson-overlay .vocab-top { display: flex; flex-direction: column; align-items: center; text-align: center; gap: 6px; }
#lesson-overlay .vocab-jp {
  font-family: var(--font-jp, "Noto Sans JP", sans-serif); font-size: 56px; font-weight: 700; line-height: 1.15;
  color: var(--ink, #1f2933); word-break: break-word;
}
#lesson-overlay .vocab-reading { font-size: 16px; color: var(--reading, #1e88e5); font-weight: 500; }
#lesson-overlay .vocab-meaning { margin-top: 6px; font-size: 22px; font-weight: 600; color: var(--ink, #1f2933); line-height: 1.35; }
#lesson-overlay .btn-audio-main {
  margin-top: 10px; height: 36px; padding: 0 14px; border-radius: 999px; cursor: pointer;
  display: inline-flex; align-items: center; gap: 6px;
  border: 1px solid var(--line, #e9edf1); background: var(--bg, #fff); color: var(--accent, #0576a6);
  font: inherit; font-size: 14px; font-weight: 600;
}
#lesson-overlay .btn-audio-main:hover { border-color: var(--accent, #0576a6); background: var(--accent-soft, #e3f3fa); }

#lesson-overlay .grammar-title {
  text-align: center; font-family: var(--font-jp, "Noto Sans JP", sans-serif);
  font-size: 30px; font-weight: 700; color: var(--ink, #1f2933); line-height: 1.3;
}
#lesson-overlay .grammar-usage {
  padding: 14px 16px; border-radius: var(--r-md, 8px); background: var(--callout, #e9f6fb);
  font-size: 15px; line-height: 1.6; color: var(--text, #37424d);
}
#lesson-overlay .grammar-usage .badge {
  display: inline-block; margin-right: 6px; padding: 1px 8px; border-radius: var(--r-sm, 4px);
  background: var(--bg, #fff); color: var(--accent, #0576a6); font-size: 12px; font-weight: 600;
}

/* Ví dụ: nhãn nhỏ + từng dòng bấm để nghe */
#lesson-overlay .example-list { display: flex; flex-direction: column; gap: 8px; }
#lesson-overlay .example-list .label {
  font-size: 12px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.06em; color: var(--faint, #a0aab4);
}
#lesson-overlay .example-row {
  display: flex; align-items: flex-start; gap: 12px; padding: 12px 14px; cursor: pointer;
  border: 1px solid var(--line, #e9edf1); border-radius: var(--r-md, 8px); background: var(--bg, #fff);
  transition: border-color 0.15s, background 0.15s;
}
#lesson-overlay .example-row:hover { border-color: var(--accent, #0576a6); background: var(--callout, #e9f6fb); }
#lesson-overlay .ex-icon {
  flex-shrink: 0; width: 32px; height: 32px; border-radius: 50%; display: grid; place-items: center;
  background: var(--accent-soft, #e3f3fa); color: var(--accent, #0576a6);
}
#lesson-overlay .ex-text { min-width: 0; display: flex; flex-direction: column; gap: 3px; padding-top: 5px; }
#lesson-overlay .ex-text .ja { font-family: var(--font-jp, "Noto Sans JP", sans-serif); font-size: 16px; color: var(--ink, #1f2933); line-height: 1.5; }
#lesson-overlay .ex-text .vi { font-size: 14px; color: var(--muted, #6b7785); line-height: 1.45; }

/* Trạng thái nút nghe (JS thêm audio-loading / audio-playing) */
#lesson-overlay .audio-loading { position: relative; opacity: 0.7; }
#lesson-overlay .audio-playing { box-shadow: 0 0 0 3px var(--accent-soft, #e3f3fa); }
#lesson-overlay .ex-icon.audio-playing,
#lesson-overlay .btn-play-big.audio-playing { background: var(--accent, #0576a6); color: var(--on-accent, #fff); }

/* ── Câu hỏi chung ───────────────────────────────────────────────── */
#lesson-overlay .quiz-container { display: flex; flex-direction: column; gap: 16px; }
#lesson-overlay .quiz-question,
#lesson-overlay .quiz-question-text {
  font-size: 20px; font-weight: 600; color: var(--ink, #1f2933); line-height: 1.45;
  font-family: var(--font, Inter, sans-serif), var(--font-jp, "Noto Sans JP", sans-serif);
}
#lesson-overlay .quiz-hint {
  padding: 10px 14px; border-radius: var(--r-md, 8px); background: var(--bg-soft, #f3f5f7);
  font-size: 14px; color: var(--muted, #6b7785); line-height: 1.5;
}
#lesson-overlay .quiz-header-icon {
  width: 40px; height: 40px; border-radius: 12px; display: grid; place-items: center;
  background: var(--accent-soft, #e3f3fa); color: var(--accent, #0576a6);
}
#lesson-overlay .options-grid { display: flex; flex-direction: column; gap: 10px; }
#lesson-overlay .quiz-option {
  padding: 14px 16px; border: 1.5px solid var(--line, #e9edf1); border-radius: var(--r-md, 8px);
  background: var(--bg, #fff); cursor: pointer; font-size: 16px; line-height: 1.45; color: var(--ink, #1f2933);
  font-family: var(--font, Inter, sans-serif), var(--font-jp, "Noto Sans JP", sans-serif);
  transition: border-color 0.15s, background 0.15s;
}
#lesson-overlay .quiz-option:hover { border-color: var(--faint, #a0aab4); }
#lesson-overlay .quiz-option.selected { border-color: var(--accent, #0576a6); background: var(--accent-soft, #e3f3fa); }
#lesson-overlay .quiz-option.correct { border-color: var(--green, #2b6f4a); background: var(--green-bg, #e8f3ec); color: var(--green, #2b6f4a); font-weight: 600; }
#lesson-overlay .quiz-option.wrong { border-color: var(--red, #a33a2c); background: var(--red-bg, #fbe9e7); color: var(--red, #a33a2c); }
#lesson-overlay .quiz-option.has-audio { display: flex; align-items: center; gap: 10px; }
#lesson-overlay .quiz-option.has-audio .opt-text { flex: 1; }

/* Nghe: nút phát to + lời dẫn */
#lesson-overlay .listening-header {
  display: flex; align-items: center; gap: 14px; padding: 14px 16px;
  border-radius: var(--r-md, 8px); background: var(--callout, #e9f6fb);
}
#lesson-overlay .listening-header p { margin: 0; font-size: 15px; color: var(--text, #37424d); }
#lesson-overlay .btn-play-big {
  flex-shrink: 0; width: 52px; height: 52px; border-radius: 50%; display: grid; place-items: center;
  border: 0; cursor: pointer; background: var(--accent, #0576a6); color: var(--on-accent, #fff);
}
#lesson-overlay .btn-play-big:hover { background: var(--accent-hover, #045e87); }
#lesson-overlay .btn-play-big svg { margin-left: 3px; fill: currentColor; }
#lesson-overlay .review-badge {
  display: inline-flex; align-items: center; gap: 5px; padding: 2px 8px; border-radius: var(--r-sm, 4px);
  background: var(--amber-bg, #fbefdf); color: var(--amber, #9a5b13); font-size: 12px; font-weight: 600;
}
#lesson-overlay .review-note { margin: 4px 0 0; font-size: 14px; color: var(--muted, #6b7785); }

/* BJT: ảnh / hội thoại / đoạn đọc */
#lesson-overlay .bjt-image img { display: block; max-width: 100%; max-height: 320px; margin: 0 auto; border-radius: var(--r-md, 8px); }
#lesson-overlay .bjt-dialogue {
  display: flex; flex-direction: column; gap: 8px; padding: 14px 16px;
  border: 1px solid var(--line, #e9edf1); border-radius: var(--r-md, 8px);
}
#lesson-overlay .bjt-line { display: flex; align-items: flex-start; gap: 10px; font-family: var(--font-jp, "Noto Sans JP", sans-serif); line-height: 1.6; }
#lesson-overlay .bjt-speaker { font-weight: 700; color: var(--accent, #0576a6); }
#lesson-overlay .bjt-speak {
  flex-shrink: 0; width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center;
  border: 0; cursor: pointer; background: var(--accent-soft, #e3f3fa); color: var(--accent, #0576a6);
}
#lesson-overlay .bjt-speak svg { width: 16px; height: 16px; }
#lesson-overlay .bjt-listen-all {
  align-self: flex-start; display: inline-flex; align-items: center; gap: 6px; height: 32px; padding: 0 12px;
  border: 1px solid var(--line, #e9edf1); border-radius: 999px; background: var(--bg, #fff); cursor: pointer;
  color: var(--accent, #0576a6); font: inherit; font-size: 13px; font-weight: 600;
}
#lesson-overlay .bjt-listen-all svg { width: 16px; height: 16px; }
#lesson-overlay .bjt-passage {
  padding: 14px 16px; border-radius: var(--r-md, 8px); background: var(--bg-soft, #f3f5f7);
  font-family: var(--font-jp, "Noto Sans JP", sans-serif); font-size: 15px; line-height: 1.8; color: var(--ink, #1f2933);
}

/* ── Sắp xếp câu / nghe rồi ghép ─────────────────────────────────── */
#lesson-overlay .scramble-zone {
  min-height: 64px; padding: 10px; display: flex; flex-wrap: wrap; align-content: flex-start; gap: 8px;
  border: 1.5px dashed var(--line, #e9edf1); border-radius: var(--r-md, 8px); background: var(--bg-soft, #f3f5f7);
  transition: border-color 0.15s, background 0.15s;
}
#lesson-overlay .scramble-zone.drag-over { border-color: var(--accent, #0576a6); }
#lesson-overlay .scramble-zone.correct-border { border-style: solid; border-color: var(--green, #2b6f4a); background: var(--green-bg, #e8f3ec); }
#lesson-overlay .scramble-zone.wrong-border { border-style: solid; border-color: var(--red, #a33a2c); background: var(--red-bg, #fbe9e7); }
#lesson-overlay .chunks-pool { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; }
#lesson-overlay .chunk-btn,
#lesson-overlay .chunk-chip {
  padding: 9px 14px; border-radius: var(--r-md, 8px); cursor: pointer; user-select: none;
  font-family: var(--font-jp, "Noto Sans JP", sans-serif); font-size: 16px; line-height: 1.3;
  border: 1px solid var(--line, #e9edf1); border-bottom-width: 3px; background: var(--bg, #fff); color: var(--ink, #1f2933);
}
#lesson-overlay .chunk-btn:hover { border-color: var(--faint, #a0aab4); }
#lesson-overlay .chunk-chip { border-color: var(--accent, #0576a6); background: var(--accent-soft, #e3f3fa); cursor: grab; }
#lesson-overlay .chunk-chip.dragging { opacity: 0.5; }
#lesson-overlay .chunk-chip.drag-hidden { display: none; }
#lesson-overlay .chunk-placeholder { border: 1.5px dashed var(--accent, #0576a6); border-radius: var(--r-md, 8px); }
#lesson-overlay .pickup-mini-progress { height: 4px; border-radius: 999px; background: var(--bg-soft, #f3f5f7); overflow: hidden; }
#lesson-overlay .pickup-mini-progress .fill { height: 100%; background: var(--green, #2b6f4a); transition: width 0.3s; }
#lesson-overlay .pickup-hint:not(:empty) {
  padding: 10px 14px; border-radius: var(--r-md, 8px); background: var(--amber-bg, #fbefdf);
  color: var(--amber, #9a5b13); font-size: 14px;
}

/* ── Ghép cặp ────────────────────────────────────────────────────── */
#lesson-overlay .matching-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
#lesson-overlay .match-card {
  min-height: 56px; padding: 12px; display: grid; place-items: center; text-align: center; cursor: pointer;
  border: 1.5px solid var(--line, #e9edf1); border-radius: var(--r-md, 8px); background: var(--bg, #fff);
  font-size: 15px; line-height: 1.4; color: var(--ink, #1f2933); word-break: break-word;
  font-family: var(--font, Inter, sans-serif), var(--font-jp, "Noto Sans JP", sans-serif);
  transition: border-color 0.15s, background 0.15s, opacity 0.3s;
}
#lesson-overlay .match-card:hover { border-color: var(--faint, #a0aab4); }
#lesson-overlay .match-card.selected { border-color: var(--accent, #0576a6); background: var(--accent-soft, #e3f3fa); }
#lesson-overlay .match-card.matched { border-color: var(--green, #2b6f4a); background: var(--green-bg, #e8f3ec); color: var(--green, #2b6f4a); opacity: 0.45; cursor: default; }
#lesson-overlay .match-card.wrong { border-color: var(--red, #a33a2c); background: var(--red-bg, #fbe9e7); animation: lp-shake 0.35s; }
#lesson-overlay .match-card.disabled { pointer-events: none; }
#lesson-overlay .match-feedback:empty { display: none; }

/* ── Điền từ ─────────────────────────────────────────────────────── */
#lesson-overlay .fill-sentence-box {
  padding: 18px 16px; border-radius: var(--r-md, 8px); border: 1px solid var(--line, #e9edf1);
  font-family: var(--font-jp, "Noto Sans JP", sans-serif); font-size: 20px; line-height: 2; color: var(--ink, #1f2933);
}
#lesson-overlay .input-wrapper { display: inline-block; position: relative; margin: 0 4px; }
#lesson-overlay .quiz-input,
#lesson-overlay .fill-input {
  width: 9em; padding: 2px 6px; border: 0; border-bottom: 2px solid var(--accent, #0576a6); border-radius: 0;
  background: var(--accent-soft, #e3f3fa); outline: none; text-align: center;
  font: inherit; color: var(--accent, #0576a6); font-weight: 600;
}
#lesson-overlay .quiz-input:focus,
#lesson-overlay .fill-input:focus { box-shadow: 0 2px 0 0 var(--accent, #0576a6); }
#lesson-overlay .quiz-input.input-success { border-color: var(--green, #2b6f4a); background: var(--green-bg, #e8f3ec); color: var(--green, #2b6f4a); }
#lesson-overlay .quiz-input.input-error { border-color: var(--red, #a33a2c); background: var(--red-bg, #fbe9e7); color: var(--red, #a33a2c); }
#lesson-overlay .input-underline { display: none; }
#lesson-overlay .shake-anim { animation: lp-shake 0.35s; }
#lesson-overlay .quiz-hint-box {
  display: flex; align-items: flex-start; gap: 8px; padding: 10px 14px; border-radius: var(--r-md, 8px);
  background: var(--amber-bg, #fbefdf); color: var(--amber, #9a5b13); font-size: 14px; line-height: 1.5;
}
#lesson-overlay .hint-icon { flex-shrink: 0; display: inline-flex; padding-top: 1px; }
#lesson-overlay .fill-zone { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; font-size: 18px; }

#lesson-overlay .error {
  padding: 14px 16px; border-radius: var(--r-md, 8px); background: var(--red-bg, #fbe9e7); color: var(--red, #a33a2c);
}

/* ── Hiệu ứng ────────────────────────────────────────────────────── */
#lesson-overlay .animate-pop-in,
#lesson-overlay .animate-slide-up,
#lesson-overlay .animate-fade-in { animation: lp-rise 0.25s ease; }
@keyframes lp-rise { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
@keyframes lp-shake { 0%, 100% { transform: none; } 25% { transform: translateX(-5px); } 75% { transform: translateX(5px); } }
@media (prefers-reduced-motion: reduce) {
  #lesson-overlay *, #lesson-overlay { animation: none !important; transition: none !important; }
}

/* Thông báo sau khi nộp bài (JS: showCelebrationToast) — nằm ngoài hộp nên không dưới #lesson-overlay */
.lp-toast {
  position: fixed; top: 24px; left: 50%; transform: translateX(-50%); z-index: 10000;
  display: flex; align-items: center; gap: 12px; max-width: calc(100vw - 32px);
  padding: 14px 20px; border-radius: 12px;
  background: var(--bg, #fff); color: var(--ink, #1f2933); border: 1px solid var(--line, #e9edf1);
  box-shadow: var(--shadow-pop, 0 8px 28px rgba(15, 23, 42, 0.14));
  font-family: var(--font, Inter, system-ui, sans-serif); font-size: 15px; font-weight: 600; line-height: 1.5;
  white-space: pre-line; transition: opacity 0.5s;
}
.lp-toast-icon {
  flex-shrink: 0; width: 38px; height: 38px; border-radius: 10px; display: grid; place-items: center;
  background: var(--green-tag, #e3f1e8); color: var(--green, #2b6f4a);
}

/* ── Điện thoại: hộp chiếm cả màn hình ───────────────────────────── */
@media (max-width: 640px) {
  #lesson-overlay { padding: 0; }
  #lesson-overlay .lesson-window { max-width: none; height: 100%; border-radius: 0; }
  #lesson-overlay .lesson-header { padding: 10px 12px; gap: 10px; }
  #lesson-overlay #lesson-content { padding: 24px 16px 32px; }
  #lesson-overlay .lesson-footer { padding: 10px 12px calc(10px + env(safe-area-inset-bottom)); flex-wrap: wrap; gap: 10px; }
  #lesson-overlay #feedback-msg:empty { display: none; }
  #lesson-overlay #feedback-msg { flex-basis: 100%; }
  #lesson-overlay .lesson-nav { width: 100%; }
  #lesson-overlay .lesson-nav-right { flex: 1; min-width: 0; }
  #lesson-overlay .vocab-jp { font-size: 44px; }
  #lesson-overlay .vocab-meaning { font-size: 19px; }
  #lesson-overlay .quiz-question, #lesson-overlay .quiz-question-text { font-size: 18px; }
  #lesson-overlay .matching-grid { gap: 8px; }
}
.lp-toast.is-error .lp-toast-icon { background: var(--red-bg, #fbe9e7); color: var(--red, #a33a2c); }