/* introFilm 20261026 (0.14.0-demo-introFilm)：站内介绍片播放层 + 登录页预览卡 + 顶栏帮助菜单。 */
.bk-intro-dialog{width:min(960px,calc(100vw - 32px));max-width:none;padding:0;border:0;border-radius:16px;background:var(--bk-bg-container,#fff);color:var(--bk-text-1,#0E1020);box-shadow:0 24px 64px rgba(14,16,32,.32);overflow:hidden}
.bk-intro-dialog::backdrop,.bk-intro-prompt::backdrop{background:rgba(14,16,32,.62)}
.bk-intro-head{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;padding:16px 20px 12px}
.bk-intro-eyebrow{font-size:12px;color:var(--bk-primary-text,#2A6DDB);font-weight:600;letter-spacing:.04em}
.bk-intro-head h2{margin:4px 0 0;font-size:18px;line-height:1.4;font-weight:600}
.bk-intro-close{border:0;background:transparent;color:var(--bk-text-3,#667085);font-size:18px;width:36px;height:36px;border-radius:8px;cursor:pointer}
.bk-intro-close:hover{background:var(--bk-bg-sunken,#EDEEF2)}
.bk-intro-frame{background:#0e1020;aspect-ratio:16/9}
.bk-intro-video{display:block;width:100%;height:100%;background:#0e1020}
.bk-intro-foot{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 20px 16px;font-size:13px;color:var(--bk-text-3,#667085)}
.bk-intro-sound,.bk-intro-btn{border:1px solid var(--bk-line-strong,#D0D4DE);background:var(--bk-bg-container,#fff);color:var(--bk-text-1,#0E1020);border-radius:9px;padding:7px 16px;font:inherit;font-size:14px;cursor:pointer}
.bk-intro-btn.primary{background:var(--bk-primary,#2A6DDB);border-color:var(--bk-primary,#2A6DDB);color:#fff}
.bk-intro-btn.primary:hover{background:var(--bk-primary-hover,#1F5BC0)}
.bk-intro-dialog button:focus-visible,.bk-intro-prompt button:focus-visible,.bk-help button:focus-visible,.bk-intro-card:focus-visible,.bk-intro-link:focus-visible{outline:3px solid var(--bk-brand-sky,#3F86F2);outline-offset:2px}
.bk-intro-prompt{width:min(440px,calc(100vw - 32px));padding:0;border:0;border-radius:16px;overflow:hidden;background:var(--bk-bg-container,#fff);color:var(--bk-text-1,#0E1020);box-shadow:0 24px 64px rgba(14,16,32,.28)}
.bk-intro-prompt-poster{display:block;width:100%;aspect-ratio:16/9;object-fit:cover;background:#0e1020}
.bk-intro-prompt-body{padding:18px 22px 20px}
.bk-intro-prompt-body h2{margin:0 0 8px;font-size:17px;line-height:1.45;font-weight:600}
.bk-intro-prompt-body p{margin:0;color:var(--bk-text-2,#4A5068);font-size:14px;line-height:1.75}
.bk-intro-prompt-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:18px}
/* 顶栏「?」帮助 */
.bk-help{position:relative;display:inline-flex}
.bk-help-toggle{font-weight:700;font-size:15px}
.bk-help-menu{position:absolute;right:0;top:calc(100% + 8px);z-index:60;min-width:220px;padding:6px;border-radius:12px;border:1px solid var(--bk-line,#E4E6EC);background:var(--bk-bg-container,#fff);box-shadow:0 12px 32px rgba(14,16,32,.16)}
.bk-help-menu[hidden]{display:none}
.bk-help-item{display:flex;flex-direction:column;align-items:flex-start;gap:2px;width:100%;border:0;background:transparent;border-radius:8px;padding:9px 12px;text-align:left;font:inherit;color:var(--bk-text-1,#0E1020);cursor:pointer}
.bk-help-item:hover,.bk-help-item:focus{background:var(--bk-bg-sunken,#EDEEF2)}
.bk-help-item-title{font-size:14px;font-weight:600}
.bk-help-item small{font-size:12px;color:var(--bk-text-3,#667085)}
/* 登录页左侧预览卡 */
.bk-intro-card{display:block;width:100%;max-width:400px;margin:32px 0 0;padding:0;border:1px solid rgba(201,167,240,.28);border-radius:14px;overflow:hidden;background:rgba(255,255,255,.04);color:#fff;text-align:left;font:inherit;cursor:pointer;transition:border-color .18s,background .18s}
.bk-intro-card:hover{border-color:rgba(201,167,240,.6);background:rgba(255,255,255,.07)}
.bk-intro-card-cover{position:relative;display:block;aspect-ratio:16/9;background:#161a33}
.bk-intro-card-cover img{display:block;width:100%;height:100%;object-fit:cover}
.bk-intro-card-play{position:absolute;left:14px;bottom:14px;width:44px;height:44px;border-radius:50%;background:rgba(14,16,32,.62);border:1px solid rgba(255,255,255,.5);display:grid;place-items:center}
.bk-intro-card-play::after{content:"";margin-left:4px;border-style:solid;border-width:8px 0 8px 13px;border-color:transparent transparent transparent #fff}
.bk-intro-card-text{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 14px}
.bk-intro-card-text strong{font-size:14px;font-weight:600}
.bk-intro-card-text small{display:block;margin-top:2px;color:#a8adbe;font-size:12px}
.bk-intro-card-cta{flex:none;font-size:13px;color:#c9a7f0;font-weight:600}
.bk-intro-link{border:0;background:transparent;padding:0;margin:0;font:inherit;color:var(--bk-primary-text,#2A6DDB);cursor:pointer;text-decoration:underline;text-underline-offset:3px}
@media (max-height:760px){.bk-intro-card{margin-top:22px;max-width:340px}}
@media (prefers-reduced-motion: reduce){.bk-intro-card{transition:none}}