/* ── COURSE HEADER ── */
.crs-hero {
  background: var(--bg2);
  border-bottom: 1px solid var(--bdr);
  padding: 28px 24px 24px;
}
.crs-hero-in {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}
.crs-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: .75rem;
  color: var(--txt3);
  margin-bottom: 14px;
}
.crs-breadcrumb a {
  color: var(--blue);
  text-decoration: none;
}
.crs-breadcrumb a:hover { text-decoration: underline; }
.crs-breadcrumb-sep { color: var(--bdr2); }
.crs-hero-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
  flex-wrap: wrap;
}
.crs-tag {
  font-size: .65rem;
  font-weight: 700;
  letter-spacing: .5px;
  text-transform: uppercase;
  padding: 3px 10px;
  border-radius:var(--md-sys-shape-corner-full);
  background: rgba(34,197,94,.1);
  color: #16a34a;
}
[data-theme="dark"] .crs-tag { background: rgba(34,197,94,.15); color: #4ade80; }
.crs-count {
  font-size: .78rem;
  color: var(--txt3);
}
.crs-hero h1 {
  font-size: clamp(1.2rem, 2.5vw, 1.6rem);
  font-weight: 900;
  color: var(--txt);
  margin: 0 0 8px;
  line-height: 1.3;
}
.crs-hero-desc {
  font-size: .88rem;
  color: var(--txt2);
  line-height: 1.7;
  max-width: 680px;
  margin: 0;
}

.crs-partner-strip{display:flex;align-items:center;gap:10px;background:var(--card);border:1px solid var(--blue);border-radius:var(--r);padding:10px 16px;margin-top:16px;text-decoration:none;font-size:.82rem;width:fit-content;max-width:100%;transition:box-shadow var(--md-sys-motion-duration-short4) var(--md-sys-motion-easing-standard),transform var(--md-sys-motion-duration-short4) var(--md-sys-motion-easing-standard)}
.crs-partner-strip:hover{box-shadow:var(--shadow-md);transform:translateY(-1px)}
.crs-partner-strip-ico{font-size:1rem;flex-shrink:0}
.crs-partner-strip strong{color:var(--txt);font-weight:800}
.crs-partner-strip .crs-partner-strip-sub{color:var(--txt2);font-weight:600}
.crs-partner-strip-arrow{color:var(--blue);font-weight:800;flex-shrink:0}
@media(max-width:640px){.crs-partner-strip{font-size:.78rem}}

/* ── MAIN LAYOUT ── */
.crs-body {
  max-width: 1200px;
  margin: 0 auto;
  padding: 28px 24px 80px;
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 28px;
  align-items: start;
}

/* ── PLAYER ── */
.crs-player-wrap {
  position: sticky;
  top: 80px;
}
.crs-player {
  background: #000;
  border-radius:var(--md-sys-shape-corner-medium);
  overflow: hidden;
  aspect-ratio: 16/9;
  width: 100%;
}
.crs-player iframe {
  width: 100%;
  height: 100%;
  border: none;
  display: block;
}
.crs-player iframe[hidden]{display:none}
/* click-to-load poster: the YouTube player (~1 MB) loads only on play */
.crs-yt-facade{position:relative;display:block;width:100%;height:100%;padding:0;border:0;background:#000;cursor:pointer}
.crs-yt-facade[hidden]{display:none}
.crs-yt-facade img{width:100%;height:100%;object-fit:cover;display:block}
.crs-yt-play{position:absolute;inset:0;margin:auto;width:68px;height:48px;border-radius:var(--md-sys-shape-corner-large);background:rgba(0,0,0,.72);transition:background var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard)}
.crs-yt-play::before{content:"";position:absolute;inset:0;margin:auto;width:0;height:0;border-style:solid;border-width:11px 0 11px 19px;border-color:transparent transparent transparent #fff;transform:translateX(2px)}
.crs-yt-facade:hover .crs-yt-play,.crs-yt-facade:focus-visible .crs-yt-play{background:#e00}
.crs-yt-facade:focus-visible{outline:3px solid var(--blue);outline-offset:-3px}
.crs-now-title {
  margin-top: 14px;
  font-size: .95rem;
  font-weight: 700;
  color: var(--txt);
  line-height: 1.4;
}
.crs-now-num {
  font-size: .78rem;
  color: var(--txt3);
  margin-top: 4px;
}
.crs-now-desc {
  margin-top: 14px;
  padding: 16px;
  background: var(--bg2);
  border: 1px solid var(--bdr);
  border-radius:var(--md-sys-shape-corner-medium);
  font-size: .83rem;
  color: var(--txt2);
  line-height: 1.75;
  white-space: pre-line;
}
.crs-next-btn {
  margin-top: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.crs-btn-next {
  flex: 1;
  background:var(--md-sys-color-primary-filled);
  color: #fff;
  border: none;
  border-radius:var(--r);
  padding: 10px 20px;
  font-size: .85rem;
  font-weight: 700;
  font-family: 'Janna LT','Janna LT Fallback','Cairo',sans-serif;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition:opacity var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.crs-btn-next:hover { opacity: .88; }
.crs-btn-next:disabled { opacity: .35; cursor: default; }
.crs-btn-done {
  background: var(--bg2);
  border: 1px solid var(--bdr);
  border-radius:var(--r);
  padding: 10px 16px;
  font-size: .82rem;
  font-weight: 600;
  font-family: 'Janna LT','Janna LT Fallback','Cairo',sans-serif;
  color: var(--txt2);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
  transition:background var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard),color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard),border-color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.crs-btn-done.done {
  background: rgba(34,197,94,.1);
  border-color: rgba(34,197,94,.3);
  color: #16a34a;
}
[data-theme="dark"] .crs-btn-done.done {
  background: rgba(34,197,94,.15);
  color: #4ade80;
}

/* Progress bar */
.crs-progress-wrap {
  padding: 12px 18px 10px;
  border-bottom: 1px solid var(--bdr);
}
.crs-progress-label {
  display: flex;
  justify-content: space-between;
  font-size: .72rem;
  color: var(--txt3);
  margin-bottom: 6px;
}
.crs-progress-label strong { color: var(--txt2); }
.crs-progress-bar {
  height: 4px;
  background: var(--bdr2);
  border-radius:var(--md-sys-shape-corner-extra-small);
  overflow: hidden;
}
.crs-progress-fill {
  height: 100%;
  background: var(--blue);
  border-radius:var(--md-sys-shape-corner-extra-small);
  transition:width var(--md-sys-motion-duration-medium2) var(--md-sys-motion-easing-standard);
}

/* Done checkmark on lesson */
.crs-lesson .crs-check {
  flex-shrink: 0;
  width: 16px;
  height: 16px;
  border-radius:50%;
  border: 1.5px solid var(--bdr2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .55rem;
  color: transparent;
  margin-top: 3px;
  transition:background var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard),border-color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard),color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.crs-lesson.watched .crs-check {
  background: #16a34a;
  border-color: #16a34a;
  color: #fff;
}

/* ── PLAYLIST ── */
.crs-playlist {
  background: var(--card);
  border: 1px solid var(--bdr);
  border-radius:var(--rl);
  overflow: hidden;
  max-height: calc(100vh - 120px);
  overflow-y: auto;
  position: sticky;
  top: 80px;
}
.crs-playlist::-webkit-scrollbar { width: 4px; }
.crs-playlist::-webkit-scrollbar-track { background: transparent; margin: 12px 0; }
.crs-playlist::-webkit-scrollbar-thumb { background: var(--bdr2); border-radius:var(--md-sys-shape-corner-extra-small); }

.crs-pl-header {
  padding: 16px 18px;
  border-bottom: 1px solid var(--bdr);
  font-size: .8rem;
  font-weight: 700;
  color: var(--txt);
  position: sticky;
  top: 0;
  background: var(--card);
  z-index: 2;
}
.crs-pl-header span { color: var(--txt3); font-weight: 400; }

.crs-group {}
.crs-sub-label {
  padding: 6px 18px 5px 18px;
  font-size: .65rem;
  font-weight: 700;
  color: var(--blue);
  background: var(--card);
  border-bottom: 1px solid var(--bdr2);
  letter-spacing: .5px;
}
.crs-group-title {
  padding: 10px 18px 8px;
  font-size: .68rem;
  font-weight: 800;
  letter-spacing: .8px;
  text-transform: uppercase;
  color: var(--txt3);
  background: var(--bg2);
  border-top: 1px solid var(--bdr);
  border-bottom: 1px solid var(--bdr);
  position: sticky;
  top: 49px;
  z-index: 1;
}

.crs-lesson {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 18px;
  cursor: pointer;
  border-bottom: 1px solid var(--bdr2);
  transition:background var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.crs-lesson:hover { background: var(--bg2); }
.crs-lesson.active { background: rgba(31,98,142,.07); }
[data-theme="dark"] .crs-lesson.active { background: rgba(74,159,212,.1); }
.crs-lesson-num {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  border-radius:50%;
  background: var(--bdr2);
  color: var(--txt3);
  font-size: .65rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 1px;
}
.crs-lesson.active .crs-lesson-num {
  background:var(--md-sys-color-primary-filled);
  color: #fff;
}
.crs-lesson-text {
  font-size: .82rem;
  color: var(--txt2);
  line-height: 1.45;
  flex: 1;
}
.crs-lesson.active .crs-lesson-text {
  color: var(--txt);
  font-weight: 600;
}

/* ── MOBILE ── */
@media (max-width: 860px) {
  .crs-body {
    grid-template-columns: 1fr;
  }
  .crs-player-wrap, .crs-playlist {
    position: static;
    max-height: none;
  }
  .crs-playlist {
    max-height: 480px;
    overflow-y: auto;
  }
}