.video-tutorial {
  --vt-bg: #ffffff;
  --vt-panel: #f4f8f5;
  --vt-text: #253f34;
  --vt-muted: #677b70;
  --vt-line: #dce7df;
  --vt-active: #eaf2ec;
  --vt-accent: #2f5d50;
  --vt-player: #eaf0ec;
  display: grid;
  grid-template-columns: 15rem minmax(0, 1fr);
  min-width: 0;
  min-height: 0;
  height: 100%;
  overflow: hidden;
  color: var(--vt-text);
  background: var(--vt-bg);
  font-family: Inter, -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  color-scheme: light;
}
.video-tutorial[data-theme="dark"] {
  --vt-bg: #0c1014;
  --vt-panel: #10171d;
  --vt-text: #eef5f8;
  --vt-muted: #94a7b1;
  --vt-line: rgba(218, 233, 238, .13);
  --vt-active: rgba(134, 187, 214, .12);
  --vt-accent: #c7fbff;
  --vt-player: #111d25;
  color-scheme: dark;
}
.video-tutorial *, .video-tutorial-page * { box-sizing: border-box; }
.video-tutorial [hidden] { display: none !important; }
.video-tutorial-directory {
  min-width: 0;
  min-height: 0;
  overflow-y: auto;
  padding: 1.5rem 1rem;
  border-right: 1px solid var(--vt-line);
  background: var(--vt-panel);
  overscroll-behavior: contain;
  scrollbar-width: thin;
}
.video-tutorial .video-tutorial-directory-heading { margin: 0 0 1.1rem; color: var(--vt-text); font-size: 1rem; font-weight: 600; }
.video-tutorial-directory-list { display: grid; gap: .35rem; margin: 0; padding: 0; list-style: none; }
.video-tutorial-directory-link { display: flex; align-items: baseline; gap: .7rem; border: 1px solid transparent; border-radius: .55rem; padding: .75rem .65rem; color: var(--vt-muted); font-size: .875rem; line-height: 1.55; text-decoration: none; transition: color .18s ease, background .18s ease; }
.video-tutorial-directory-link:hover { color: var(--vt-accent); background: var(--vt-active); }
.video-tutorial-directory-link[aria-current="true"] { color: var(--vt-accent); border-color: var(--vt-line); background: var(--vt-active); }
.video-tutorial-directory-link:focus-visible { outline: 2px solid var(--vt-accent); outline-offset: 2px; }
.video-tutorial-number { flex: none; font-size: .75rem; font-variant-numeric: tabular-nums; opacity: .7; }
.video-tutorial-link-title { overflow-wrap: anywhere; }
.video-tutorial-videos { min-width: 0; min-height: 0; padding: 1.5rem clamp(1rem, 4vw, 3rem) 3rem; overflow-y: auto; overscroll-behavior: contain; scrollbar-color: var(--vt-muted) var(--vt-bg); }
.video-tutorial-card { padding: 0 0 2.5rem; margin: 0 0 2rem; border-bottom: 1px solid var(--vt-line); scroll-margin-top: 1.5rem; }
.video-tutorial-card:last-child { margin-bottom: 0; padding-bottom: 0; border-bottom: 0; }
.video-tutorial-card-heading { margin: 0 auto 1rem; max-width: 34rem; text-align: center; }
.video-tutorial-card-heading h3 { margin: 0; color: var(--vt-text); font-size: clamp(1.05rem, 2vw, 1.3rem); line-height: 1.5; font-weight: 550; overflow-wrap: anywhere; }
.video-tutorial .video-tutorial-card-heading p { margin: .5rem 0 0; color: var(--vt-muted); font-size: .85rem; line-height: 1.7; }
.video-tutorial-player { position: relative; width: min(100%, 19rem); aspect-ratio: 9 / 16; margin: 0 auto; overflow: hidden; border: 1px solid var(--vt-line); border-radius: .8rem; background: var(--vt-player); }
.video-tutorial-player video { display: block; width: 100%; height: 100%; background: #05080a; object-fit: contain; }
.video-tutorial-placeholder { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: .5rem; height: 100%; padding: 1.25rem; background: radial-gradient(ellipse at 50% 32%, var(--vt-active), transparent 75%); text-align: center; }
.video-tutorial-play-symbol { display: grid; place-items: center; width: 3.5rem; height: 3.5rem; margin-bottom: .7rem; border: 1px solid var(--vt-line); border-radius: 50%; color: var(--vt-accent); font-size: 1.8rem; line-height: 1; }
.video-tutorial-placeholder strong { color: var(--vt-text); font-size: .95rem; font-weight: 550; }
.video-tutorial .video-tutorial-placeholder p { margin: 0; color: var(--vt-muted); font-size: .75rem; line-height: 1.7; }
.video-tutorial-status { grid-column: 1 / -1; padding: 1rem; color: var(--vt-muted); text-align: center; }
.video-tutorial-empty { display: flex; flex-direction: column; align-items: center; justify-content: center; min-height: 100%; text-align: center; }
.video-tutorial-empty h3 { margin: .5rem 0; color: var(--vt-text); font-size: 1.15rem; }
.video-tutorial .video-tutorial-empty p, .video-tutorial .video-tutorial-empty-directory { color: var(--vt-muted); font-size: .85rem; line-height: 1.7; }

.video-tutorial-page { margin: 0; padding: 1.5rem; background: #f2f5f2; font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif; }
.video-tutorial-page-shell { display: grid; grid-template-rows: auto minmax(0, 1fr); width: min(100%, 64rem); height: calc(100dvh - 3rem); min-height: 20rem; margin: 0 auto; overflow: hidden; border: 1px solid #dce7df; border-radius: 1rem; background: #ffffff; }
.video-tutorial-page-heading { padding: 1.25rem 1.5rem; border-bottom: 1px solid #dce7df; }
.video-tutorial-page-heading p { margin: 0 0 .3rem; color: #677b70; font-size: .75rem; letter-spacing: .08em; }
.video-tutorial-page-heading h1 { margin: 0; color: #2f5d50; font-size: 1.3rem; line-height: 1.5; }

@media (max-width: 700px) {
  .video-tutorial { grid-template-columns: minmax(0, 1fr); grid-template-rows: auto minmax(0, 1fr); }
  .video-tutorial-directory { max-height: min(12rem, 30dvh); padding: .8rem 1rem; border-right: 0; border-bottom: 1px solid var(--vt-line); }
  .video-tutorial .video-tutorial-directory-heading { margin-bottom: .6rem; font-size: .85rem; }
  .video-tutorial-directory-list { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .3rem; }
  .video-tutorial-directory-link { gap: .45rem; padding: .55rem .5rem; font-size: .78rem; }
  .video-tutorial-videos { padding: 1.25rem 1rem 2rem; }
  .video-tutorial-player { width: min(100%, 19rem); }
  .video-tutorial-page { padding: 0; }
  .video-tutorial-page-shell { height: 100dvh; min-height: 0; border: 0; border-radius: 0; }
  .video-tutorial-page-heading { padding: .9rem 1rem; }
  .video-tutorial-page-heading h1 { font-size: 1.1rem; }
}
@media (prefers-reduced-motion: reduce) {
  .video-tutorial-directory-link { transition: none; }
}