/* ---------- Listening Lab: cùng phong cách tem Đông Hồ với trang chủ ---------- */
:root {
  --bg: #F5E6C8;        /* Giấy điệp */
  --bg-fiber: #E8D5B0;
  --paper-grain: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='paperNoise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='3' stitchTiles='stitch'/%3E%3CfeColorMatrix type='matrix' values='1 0 0 0 0  0 0.9 0 0 0  0 0 0.7 0 0  0 0 0 0.28 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23paperNoise)'/%3E%3C/svg%3E");
  --ink-black: #1A1A1A;
  --paper: #FFFBF0;
  --cream: #FFF6E3;
  --muted: #6B5B45;
  --vermilion: #C83228;
  --indigo: #1B4D3E;
  --blue: #2E4A7D;
  --ink: #1F1D24;
  --teal: #1A535C;      /* Xanh cổ vịt */
  --terracotta: #A84B26;
  --yellow: #E6B422;
  --right: #1B6B3A;
  --wrong: #B3261E;
  --radius: 18px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: 'Plus Jakarta Sans', 'Segoe UI', Tahoma, sans-serif;
  color: var(--ink-black);
  background-color: var(--bg);
  background-image:
    var(--paper-grain),
    radial-gradient(ellipse at 50% 35%, transparent 45%, var(--bg-fiber) 100%);
  background-size: 180px 180px, 100% 100%;
  background-blend-mode: multiply, normal;
  min-height: 100vh;
  line-height: 1.55;
}

[hidden] { display: none !important; }

.container {
  width: min(1280px, 94vw);
  margin: 0 auto;
  padding: 24px 0 48px;
}

/* ---------- Đầu trang ---------- */
.lab-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 22px;
}

.lab-header h1 {
  margin: 0;
  font-family: 'Fraunces', Georgia, serif;
  font-size: clamp(1.6rem, 3.2vw, 2.3rem);
  line-height: 1.1;
}

.home-link,
.back-btn {
  flex-shrink: 0;
  display: inline-block;
  padding: 7px 16px;
  font: 800 0.9rem 'Plus Jakarta Sans', sans-serif;
  color: var(--ink-black);
  text-decoration: none;
  background: var(--cream);
  border: 2px solid var(--ink-black);
  border-radius: 999px;
  box-shadow: 0 3px 0 var(--ink-black);
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

/* Nút Sổ câu sai ở góc phải đầu trang */
.review-link { margin-left: auto; }
.review-link b { color: var(--vermilion); }

.home-link:hover,
.back-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 0 var(--ink-black);
}

/* ---------- Thanh chọn level ---------- */
.level-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-bottom: 26px;
}

.level-tab {
  --tab-bg: var(--yellow);
  --tab-ink: var(--ink-black);
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-areas: "code name" "code count";
  align-items: center;
  column-gap: 14px;
  padding: 12px 18px;
  text-align: left;
  font-family: inherit;
  color: var(--ink-black);
  background: var(--paper);
  border: 2px solid var(--ink-black);
  border-radius: 4px;
  box-shadow: 4px 4px 0 var(--ink-black);
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

.level-tab:hover { transform: translate(-1px, -1px); box-shadow: 5px 5px 0 var(--ink-black); }

.level-tab[aria-selected="true"] {
  background: var(--tab-bg);
  color: var(--tab-ink);
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 var(--ink-black);
}

.level-a2 { --tab-bg: var(--yellow); --tab-ink: var(--ink-black); }
.level-b1 { --tab-bg: var(--terracotta); --tab-ink: var(--cream); }
.level-b2 { --tab-bg: var(--teal); --tab-ink: var(--cream); }

.level-code {
  grid-area: code;
  font-family: 'Fraunces', Georgia, serif;
  font-size: 2rem;
  line-height: 1;
}

.level-name {
  grid-area: name;
  font-weight: 800;
  font-size: 0.95rem;
}

.level-count {
  grid-area: count;
  font-size: 0.78rem;
  font-weight: 600;
  opacity: 0.75;
}

/* ---------- Thẻ bài nghe dạng tem ---------- */
.lesson-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 22px;
}

.stamp {
  --perf: 6px;
  --stamp-paper: var(--paper);
  --stamp-bg: var(--blue);
  --stamp-ink: var(--cream);
  display: flex;
  padding: calc(2 * var(--perf));
  background:
    radial-gradient(var(--perf), #0000 98%, var(--stamp-paper)) round
      calc(-1.5 * var(--perf)) calc(-1.5 * var(--perf)) / calc(3 * var(--perf)) calc(3 * var(--perf)),
    linear-gradient(var(--stamp-paper) 0 0) no-repeat
      50% / calc(100% - 3 * var(--perf)) calc(100% - 3 * var(--perf));
  filter: drop-shadow(0 6px 8px rgba(96, 65, 18, 0.2));
  transition: transform 0.2s ease, filter 0.2s ease;
}

.stamp:hover {
  transform: translateY(-4px) rotate(-0.6deg);
  filter: drop-shadow(0 12px 14px rgba(96, 65, 18, 0.26));
}

/* Màu tem đồng bộ theo Level */
.stamp--a2 {
  --stamp-bg: var(--yellow);
  --stamp-ink: var(--ink-black);
}
.stamp--a2 .tag:not(.tag-best) {
  background: rgba(255, 255, 255, 0.45);
  border-color: var(--ink-black);
  color: var(--ink-black);
}

.stamp--b1 {
  --stamp-bg: var(--terracotta);
  --stamp-ink: var(--cream);
}
.stamp--b1 .tag:not(.tag-best) {
  background: rgba(0, 0, 0, 0.25);
  border-color: rgba(255, 246, 227, 0.85);
  color: var(--cream);
}

.stamp--b2 {
  --stamp-bg: var(--teal);
  --stamp-ink: var(--cream);
}
.stamp--b2 .tag:not(.tag-best) {
  background: rgba(0, 0, 0, 0.22);
  border-color: rgba(255, 246, 227, 0.85);
  color: var(--cream);
}

.stamp--bbc { --stamp-bg: var(--blue); }
.stamp--vtv { --stamp-bg: var(--vermilion); }

.stamp-inner {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 12px 12px 14px;
  background: var(--stamp-bg);
  color: var(--stamp-ink);
  border: 2px solid var(--ink-black);
  border-radius: 3px;
}

.stamp-inner::after {
  content: "";
  position: absolute;
  z-index: -1;
  inset: 0;
  background-image: var(--paper-grain);
  background-size: 180px 180px;
  mix-blend-mode: multiply;
  opacity: 0.4;
  pointer-events: none;
}

.lesson-thumb {
  position: relative;
  aspect-ratio: 16 / 9;
  background: rgba(0, 0, 0, 0.25);
  border: 2px solid var(--ink-black);
  border-radius: 2px;
  overflow: hidden;
}

.lesson-thumb img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.lesson-time {
  position: absolute;
  right: 6px;
  bottom: 6px;
  padding: 1px 7px;
  font-size: 0.75rem;
  font-weight: 800;
  color: #fff;
  background: rgba(0, 0, 0, 0.75);
  border-radius: 4px;
}

.lesson-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tag {
  padding: 2px 9px;
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.3px;
  text-transform: uppercase;
  border: 1.5px solid currentColor;
  border-radius: 999px;
}

.tag-best {
  color: var(--ink-black);
  background: #F2D27C;
  border-color: var(--ink-black);
}

.lesson-card h3 {
  margin: 2px 0 0;
  font-family: 'Fraunces', Georgia, serif;
  font-size: 1.3rem;
  line-height: 1.2;
}

.lesson-meta {
  margin: 0;
  font-size: 0.82rem;
  opacity: 0.85;
}

.btn {
  display: inline-block;
  padding: 8px 20px;
  font: 800 0.92rem 'Plus Jakarta Sans', sans-serif;
  color: var(--ink-black);
  text-align: center;
  text-decoration: none;
  background: var(--cream);
  border: 2px solid var(--ink-black);
  border-radius: 999px;
  box-shadow: 0 3px 0 var(--ink-black);
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

.btn:hover {
  background: #fff;
  transform: translateY(-1px);
  box-shadow: 0 4px 0 var(--ink-black);
}

.lesson-card .btn {
  align-self: flex-start;
  margin-top: auto;
}

/* ---------- Bài làm ---------- */
.lesson-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 18px;
}

.lesson-bar h2 {
  margin: 0;
  font-family: 'Fraunces', Georgia, serif;
  font-size: clamp(1.25rem, 2.4vw, 1.7rem);
  line-height: 1.15;
}

.level-chip {
  padding: 3px 12px;
  font-family: 'Fraunces', Georgia, serif;
  font-size: 1.05rem;
  color: var(--tab-ink);
  background: var(--tab-bg);
  border: 2px solid var(--ink-black);
  border-radius: 4px;
}

.lesson-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: 26px;
  align-items: start;
}

.video-col {
  position: sticky;
  top: 16px;
}

/* Khung video như ô tranh có viền mực */
.player-frame {
  padding: 10px;
  background: var(--ink);
  border: 2px solid var(--ink-black);
  border-radius: 4px;
  box-shadow: 5px 5px 0 rgba(26, 26, 26, 0.85);
}

.player-box {
  position: relative;
  aspect-ratio: 16 / 9;
  background: #000;
}

.player-box iframe,
.player-box > div {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.lesson-source {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  align-items: center;
  margin: 10px 2px 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.lesson-source a { color: inherit; font-weight: 700; }

.lesson-source .yt-link {
  margin-left: auto;
  color: var(--vermilion);
}

/* Phiếu câu hỏi kiểu đề IELTS */
.question-sheet {
  padding: 4px 22px 10px;
  background: #FFFDF7;
  border: 2px solid var(--ink-black);
  border-radius: 4px;
  box-shadow: 5px 5px 0 rgba(26, 26, 26, 0.85);
}

.q-part + .q-part {
  border-top: 2px dashed #CDB98F;
}

.q-part h3 {
  margin: 18px 0 2px;
  font-size: 1.05rem;
  font-weight: 800;
}

.q-instr {
  margin: 0 0 10px;
  font-size: 0.92rem;
  font-style: italic;
  color: var(--muted);
}

.q-heading {
  margin: 0 0 8px;
  font-family: 'Fraunces', Georgia, serif;
  font-size: 1.1rem;
  text-align: center;
}

.q-list {
  list-style: none;
  margin: 0 0 14px;
  padding: 0;
}

.q-item {
  padding: 9px 10px;
  border-radius: 6px;
  border-left: 4px solid transparent;
}

.q-item + .q-item { margin-top: 4px; }

.q-text {
  margin: 0;
  font-weight: 600;
  line-height: 1.9;
}

.q-num {
  display: inline-grid;
  place-items: center;
  min-width: 26px;
  height: 26px;
  margin-right: 9px;
  padding: 0 4px;
  font-size: 0.8rem;
  font-weight: 800;
  border: 2px solid var(--ink-black);
  border-radius: 3px;
  vertical-align: 1px;
}

.gap-input {
  width: 9.5em;
  margin: 0 6px;
  padding: 2px 8px;
  font: 700 1rem 'Plus Jakarta Sans', sans-serif;
  color: var(--blue);
  background: transparent;
  border: 0;
  border-bottom: 2px dotted var(--ink-black);
  border-radius: 0;
}

.gap-input:focus {
  outline: none;
  background: #FFF3CF;
  border-bottom-style: solid;
}

.q-options {
  display: grid;
  gap: 4px;
  margin: 6px 0 0 35px;
}

.q-option {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 5px 8px;
  border-radius: 6px;
  cursor: pointer;
}

.q-option:hover { background: #FFF3CF; }

.q-option input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.q-letter {
  flex-shrink: 0;
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  font-weight: 800;
  font-size: 0.85rem;
  border: 2px solid var(--ink-black);
  border-radius: 50%;
  transition: background 0.15s ease, color 0.15s ease;
}

.q-option input:checked + .q-letter {
  color: var(--cream);
  background: var(--blue);
  border-color: var(--blue);
}

.q-option input:focus-visible + .q-letter {
  outline: 3px solid var(--yellow);
  outline-offset: 2px;
}

/* Sau khi chấm */
.q-item.is-right { background: rgba(27, 107, 58, 0.08); border-left-color: var(--right); }
.q-item.is-wrong { background: rgba(179, 38, 30, 0.07); border-left-color: var(--wrong); }

.q-item.is-wrong .q-option.is-answer .q-letter,
.q-item.is-right .q-option.is-answer .q-letter {
  color: #fff;
  background: var(--right);
  border-color: var(--right);
}

.q-item.is-wrong .q-option input:checked + .q-letter {
  background: var(--wrong);
  border-color: var(--wrong);
}

.q-item.is-right .gap-input { color: var(--right); }
.q-item.is-wrong .gap-input { color: var(--wrong); text-decoration: line-through; }

.q-option:has(input:disabled) { cursor: default; }
.q-option:has(input:disabled):hover { background: none; }

.q-feedback:empty { display: none; }

.q-feedback {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px 12px;
  margin: 6px 0 0 35px;
  font-size: 0.88rem;
}

.fb-mark {
  font-weight: 800;
  font-size: 1.05rem;
}

.is-right .fb-mark { color: var(--right); }
.is-wrong .fb-mark { color: var(--wrong); }

.replay-btn {
  padding: 2px 10px;
  font: 800 0.8rem 'Plus Jakarta Sans', sans-serif;
  color: var(--cream);
  background: var(--ink);
  border: 2px solid var(--ink-black);
  border-radius: 999px;
  cursor: pointer;
}

.replay-btn:hover { background: var(--vermilion); }

.score-box {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 18px;
  padding: 12px 18px;
  background: var(--cream);
  border: 2px solid var(--ink-black);
  border-radius: 4px;
}

.score-box.is-perfect { background: #F2D27C; }

.score-num {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 2.2rem;
  line-height: 1;
}

.score-num small { font-size: 1.1rem; opacity: 0.7; }

.score-note { font-weight: 700; }

.sheet-actions {
  display: flex;
  gap: 12px;
  margin-top: 18px;
}

.btn-check {
  color: var(--cream);
  background: var(--vermilion);
}

.btn-check:hover { background: #A9281F; }

button:focus-visible,
a:focus-visible {
  outline: 3px solid var(--yellow);
  outline-offset: 3px;
}

/* ---------- Màn hình hẹp ---------- */
@media (max-width: 900px) {
  .lesson-layout { grid-template-columns: 1fr; }
  .video-col { position: static; }
}

@media (max-width: 640px) {
  .container { width: auto; margin: 0 16px; }
  .level-tabs { gap: 8px; }
  .level-tab {
    grid-template-columns: 1fr;
    grid-template-areas: "code" "name";
    padding: 10px 8px;
    text-align: center;
    row-gap: 4px;
  }
  .level-count { display: none; }
  .level-name { font-size: 0.72rem; }
  .question-sheet { padding: 2px 12px 8px; }
  .q-options, .q-feedback { margin-left: 0; }
  .gap-input { width: 7.5em; }
}