.listening-course {
  --lc-ink: #173c37;
  --lc-green: #16776c;
  --lc-muted: #61746f;
  --lc-border: #d7e5df;
  --lc-paper: #fff;
  --lc-tint: #eef7f3;
  color: var(--lc-ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.65;
  width: 100%;
  min-width: 0;
}

.listening-course *, .listening-course *::before, .listening-course *::after { box-sizing: border-box; }
.listening-course h1, .listening-course h2, .listening-course h3, .listening-course p { margin-top: 0; }
.listening-course h1 { font-size: clamp(1.75rem, 3.5vw, 2.5rem); line-height: 1.2; letter-spacing: -.04em; margin-bottom: 16px; }
.listening-course h2 { font-size: 1.4rem; line-height: 1.45; margin-bottom: 12px; }
.listening-course h3 { font-size: 1.05rem; line-height: 1.5; margin-bottom: 14px; }
.listening-course button, .listening-course input, .listening-course textarea { font: inherit; }
.listening-course button { cursor: pointer; }
.listening-course button:disabled { cursor: not-allowed; opacity: .5; }
.listening-course :is(button, input, textarea, a, summary):focus-visible { outline: 3px solid #a9ba44; outline-offset: 3px; }
.listening-course a { color: var(--lc-green); text-underline-offset: 3px; overflow-wrap: anywhere; }
.listening-course summary { cursor: pointer; font-weight: 700; }
.listening-course summary::marker { color: var(--lc-green); }
.listening-course [open] > summary { margin-bottom: 18px; }
.listening-course fieldset { padding: 0; border: 0; margin: 0 0 18px; min-width: 0; }
.listening-course legend { font-weight: 600; margin-bottom: 14px; width: 100%; }
.listening-course input[type="radio"], .listening-course input[type="checkbox"] { width: 18px; height: 18px; margin: 4px 0 0; flex: 0 0 auto; accent-color: var(--lc-green); }
.listening-course .lc-intro { padding: 14px 0 28px; }
.listening-course .lc-kicker { display: block; color: var(--lc-green); font-size: .78rem; font-weight: 700; letter-spacing: .08em; margin-bottom: 10px; }
.listening-course .lc-lead { max-width: 650px; color: var(--lc-muted); margin-bottom: 26px; }
.listening-course .lc-evidence-path { padding: 0; margin: 0; display: grid; grid-template-columns: repeat(3, 1fr); list-style: none; border-top: 2px solid var(--lc-green); border-bottom: 1px solid var(--lc-border); }
.listening-course .lc-evidence-path li { display: flex; align-items: baseline; gap: 15px; padding: 17px 22px; position: relative; }
.listening-course .lc-evidence-path li:first-child { padding-left: 0; }
.listening-course .lc-evidence-path li:not(:last-child)::after { content: "→"; position: absolute; right: -5px; color: var(--lc-green); font-size: 1.25rem; }
.listening-course .lc-evidence-path strong { font-size: 1.25rem; white-space: nowrap; }
.listening-course .lc-evidence-path span { color: var(--lc-muted); font-size: .82rem; }
.listening-course .lc-progress-line { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.listening-course .lc-progress-line label { font-size: .86rem; }
.listening-course .lc-progress-line strong { padding-left: 10px; color: var(--lc-green); font-variant-numeric: tabular-nums; }
.listening-course progress { appearance: none; border: none; width: 180px; max-width: 100%; height: 6px; border-radius: 3px; color: var(--lc-green); background: var(--lc-border); overflow: hidden; }
.listening-course progress::-webkit-progress-bar { background: var(--lc-border); }
.listening-course progress::-webkit-progress-value { background: var(--lc-green); }
.listening-course progress::-moz-progress-bar { background: var(--lc-green); }
.listening-course .lc-sync-note { font-size: .78rem; color: var(--lc-muted); margin: 10px 0 24px; }
.listening-course .lc-layout { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 28px; align-items: start; }
.listening-course .lc-lessons { min-width: 0; position: sticky; top: 20px; }
.listening-course .lc-nav-heading { font-size: .8rem; color: var(--lc-muted); margin: 0 0 12px 12px; }
.listening-course .lc-lesson-link { width: 100%; text-align: left; display: flex; align-items: flex-start; gap: 12px; padding: 15px 12px; color: var(--lc-ink); background: transparent; border: 1px solid transparent; border-radius: 10px; margin-bottom: 5px; }
.listening-course .lc-lesson-link:hover { background: #f4f8f6; }
.listening-course .lc-lesson-link.is-active { border-color: var(--lc-border); background: var(--lc-tint); }
.listening-course .lc-lesson-number { color: var(--lc-green); font-size: .8rem; font-variant-numeric: tabular-nums; padding-top: 2px; }
.listening-course .lc-lesson-link strong { display: block; font-size: .9rem; font-weight: 650; line-height: 1.5; }
.listening-course .lc-lesson-link small { display: block; font-size: .75rem; color: var(--lc-muted); margin-top: 5px; }
.listening-course .lc-lessons > .lc-small { padding: 12px; margin: 0; }
.listening-course .lc-lesson-body { background: var(--lc-paper); border: 1px solid var(--lc-border); border-radius: 16px; padding: 32px; min-width: 0; }
.listening-course .lc-lesson-header { border-bottom: 1px solid var(--lc-border); padding-bottom: 24px; }
.listening-course .lc-goal { font-size: .94rem; color: var(--lc-muted); margin-bottom: 0; }
.listening-course .lc-goal strong { color: var(--lc-ink); }
.listening-course .lc-section { padding-top: 28px; }
.listening-course .lc-steps { margin: 0; padding-left: 22px; }
.listening-course .lc-steps li { padding-left: 6px; margin-bottom: 12px; font-size: .93rem; }
.listening-course .lc-steps li::marker { color: var(--lc-green); font-weight: 700; }
.listening-course .lc-example { margin-top: 26px; padding: 22px; background: var(--lc-tint); border-left: 3px solid var(--lc-green); border-radius: 0 10px 10px 0; }
.listening-course .lc-section-top { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-bottom: 14px; }
.listening-course .lc-section-top h3 { margin: 0; }
.listening-course .lc-tag { font-size: .69rem; color: var(--lc-green); border: 1px solid #bdd8cd; border-radius: 4px; padding: 1px 6px; }
.listening-course .lc-english { font-family: Georgia, "Times New Roman", serif; font-size: 1.18rem; line-height: 1.8; overflow-wrap: anywhere; margin: 0 0 16px; }
.listening-course .lc-translation { font-size: .88rem; margin-bottom: 16px; }
.listening-course .lc-translation summary { color: var(--lc-green); font-weight: 500; }
.listening-course .lc-translation[open] > summary { margin-bottom: 10px; }
.listening-course .lc-translation p { margin-bottom: 0; }
.listening-course .lc-audio-controls { display: flex; gap: 10px; flex-wrap: wrap; margin: 16px 0 10px; }
.listening-course .lc-button { display: inline-flex; justify-content: center; align-items: center; min-height: 42px; padding: 9px 16px; border: 1px solid var(--lc-border); border-radius: 8px; background: var(--lc-paper); color: var(--lc-ink); font-size: .85rem; font-weight: 600; line-height: 1.4; }
.listening-course .lc-button:hover:not(:disabled) { border-color: var(--lc-green); background: var(--lc-tint); }
.listening-course .lc-button.lc-primary { background: var(--lc-green); border-color: var(--lc-green); color: white; }
.listening-course .lc-button.lc-primary:hover:not(:disabled) { background: #115f56; }
.listening-course .lc-small { font-size: .78rem; color: var(--lc-muted); line-height: 1.65; }
.listening-course .lc-example > .lc-small { margin: 0; }
.listening-course .lc-speech-status { font-size: .78rem; color: var(--lc-green); margin: 6px 0 0; }
.listening-course .lc-speech-status:empty { display: none; }
.listening-course .lc-option { display: flex; align-items: flex-start; gap: 10px; padding: 13px 14px; margin: 9px 0 0; border: 1px solid var(--lc-border); border-radius: 8px; cursor: pointer; font-size: .91rem; }
.listening-course .lc-option.is-selected { border-color: var(--lc-green); background: #f4faf7; }
.listening-course .lc-option-letter { color: var(--lc-green); font-size: .8rem; padding-top: 1px; }
.listening-course .lc-feedback { margin-top: 18px; border-left: 3px solid #ad8532; background: #fbf8f0; padding: 14px 16px; font-size: .9rem; }
.listening-course .lc-feedback.is-correct { border-left-color: var(--lc-green); background: var(--lc-tint); }
.listening-course .lc-feedback p { margin: 7px 0 0; }
.listening-course .lc-task { display: flex; align-items: flex-start; gap: 12px; padding: 12px 0; border-bottom: 1px solid var(--lc-border); cursor: pointer; font-size: .9rem; }
.listening-course .lc-task:first-of-type { padding-top: 0; }
.listening-course .lc-note-prompt { display: block; margin-bottom: 12px; font-size: .9rem; }
.listening-course textarea { display: block; width: 100%; min-height: 126px; resize: vertical; padding: 14px; border: 1px solid var(--lc-border); border-radius: 9px; color: var(--lc-ink); background: white; font-size: 1rem; line-height: 1.7; }
.listening-course textarea::placeholder { color: #75867f; font-size: .86rem; }
.listening-course .lc-note-footer { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; margin: 12px 0; }
.listening-course .lc-unsaved { color: #8a5b22; }
.listening-course .lc-complete-box { border-top: 1px solid var(--lc-border); margin-top: 28px; padding-top: 22px; }
.listening-course .lc-completed-label { color: var(--lc-green); font-weight: 700; font-size: .9rem; margin-bottom: 10px; }
.listening-course .lc-page-controls { display: flex; justify-content: space-between; gap: 14px; margin-top: 24px; }
.listening-course .lc-coach-guide, .listening-course .lc-weekly-plan, .listening-course .lc-sources { border-top: 1px solid var(--lc-border); margin-top: 30px; padding-top: 24px; }
.listening-course .lc-coach-session { margin: 0; padding: 0; list-style: none; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px 32px; }
.listening-course .lc-coach-session li { display: flex; gap: 14px; align-items: baseline; font-size: .9rem; }
.listening-course .lc-coach-minutes { color: var(--lc-green); font-size: .8rem; white-space: nowrap; min-width: 58px; }
.listening-course .lc-coach-session p { margin: 5px 0 0; color: var(--lc-muted); }
.listening-course .lc-weekly-plan h2 { font-size: 1.1rem; }
.listening-course .lc-weekly-plan ol { padding-left: 23px; margin: 0; }
.listening-course .lc-weekly-plan li { padding-left: 6px; margin: 10px 0; font-size: .9rem; }
.listening-course .lc-weekly-plan li::marker { color: var(--lc-green); font-weight: 700; }
.listening-course .lc-sources { padding-bottom: 16px; font-size: .85rem; }
.listening-course .lc-sources ul { padding-left: 20px; }
.listening-course .lc-sources li { padding-left: 3px; }
.listening-course .lc-sources p { color: var(--lc-muted); margin: 6px 0 12px; }
.listening-course .lc-sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }

@media (max-width: 960px) {
  .listening-course .lc-evidence-path li { flex-direction: column; gap: 3px; padding: 14px 18px; }
  .listening-course .lc-layout { grid-template-columns: 180px minmax(0, 1fr); gap: 18px; }
  .listening-course .lc-lesson-body { padding: 24px; }
}

@media (max-width: 680px) {
  .listening-course .lc-intro { padding: 5px 0 22px; }
  .listening-course .lc-lead { font-size: .9rem; margin-bottom: 22px; }
  .listening-course .lc-evidence-path li { padding: 12px 9px; gap: 4px; }
  .listening-course .lc-evidence-path strong { font-size: 1.05rem; }
  .listening-course .lc-evidence-path span { font-size: .69rem; }
  .listening-course .lc-evidence-path li:not(:last-child)::after { top: 10px; font-size: 1.1rem; }
  .listening-course .lc-progress-line { gap: 10px; }
  .listening-course progress { flex: 1; min-width: 60px; }
  .listening-course .lc-layout { display: block; }
  .listening-course .lc-lessons { position: static; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 6px; margin-bottom: 18px; }
  .listening-course .lc-nav-heading { grid-column: 1 / -1; margin: 0 0 4px; }
  .listening-course .lc-lesson-link { padding: 11px 9px; margin: 0; gap: 8px; border-color: var(--lc-border); }
  .listening-course .lc-lesson-link strong { font-size: .81rem; }
  .listening-course .lc-lesson-link small { font-size: .68rem; }
  .listening-course .lc-lesson-number { font-size: .69rem; }
  .listening-course .lc-lessons > .lc-small { grid-column: 1 / -1; margin: 0; padding: 6px 0 0; }
  .listening-course .lc-lesson-body { padding: 22px 16px; border-radius: 12px; }
  .listening-course .lc-lesson-header h2 { font-size: 1.25rem; }
  .listening-course .lc-goal, .listening-course .lc-steps li { font-size: .89rem; }
  .listening-course .lc-example { padding: 17px 14px; }
  .listening-course .lc-english { font-size: 1.08rem; }
  .listening-course .lc-option { padding: 12px 10px; gap: 8px; font-size: .88rem; }
  .listening-course .lc-note-footer { align-items: flex-start; flex-direction: column; gap: 8px; }
  .listening-course .lc-coach-session { grid-template-columns: 1fr; gap: 18px; }
  .listening-course .lc-button { min-height: 44px; }
}

@media (prefers-reduced-motion: reduce) {
  .listening-course *, .listening-course *::before, .listening-course *::after { scroll-behavior: auto !important; transition: none !important; animation: none !important; }
}