.learn-root{max-width:1360px;margin:0 auto;padding:clamp(26px,5vw,64px) 28px 96px;color:var(--text,#e8e8ec);font:400 16px/1.7 var(--body,'Noto Sans SC',system-ui,sans-serif);background-image:radial-gradient(color-mix(in srgb,var(--line,rgba(255,255,255,.1)) 55%,transparent) 1px,transparent 1.4px);background-size:22px 22px}
@media(max-width:720px){.learn-root{padding-left:18px;padding-right:18px}}
/* 刊头：覆盖全局 header{position:sticky;background;backdrop-filter} 以免继承站点导航栏皮肤 */
.ln-mast{position:relative;top:auto;z-index:auto;display:flex;align-items:flex-end;justify-content:space-between;gap:20px;flex-wrap:wrap;padding-bottom:20px;margin-bottom:30px;border-bottom:2px solid var(--c,var(--amber,#f5a623));background:none;backdrop-filter:none;transition:none}
.ln-mast__l .kicker{display:flex;align-items:center;gap:12px;font:700 12px/1 var(--body,system-ui);letter-spacing:.32em;text-transform:uppercase;color:var(--c,var(--amber,#f5a623));margin:0 0 12px}
.ln-mast__l .kicker::before{content:"";width:34px;height:2px;background:var(--c,var(--amber,#f5a623));border-radius:2px}
.ln-mast__l h1{margin:0;font:800 clamp(28px,5.6vw,46px)/1.05 var(--body,system-ui);letter-spacing:-.02em;color:var(--text,#f2f2f5)}
.ln-mast__r{font:700 13px/1.5 var(--body,system-ui);color:var(--dim,#7c7c86);text-align:right;max-width:300px}
/* 阶段时间线：左侧竖线 + 阶段节点，最特征的"闯关"元素 */
.ln-stage{position:relative;display:grid;grid-template-columns:64px 1fr;gap:0 22px;margin:0 0 14px}
.ln-rail{position:relative;display:flex;flex-direction:column;align-items:center}
.ln-dot{position:relative;z-index:2;width:46px;height:46px;border-radius:50%;display:grid;place-items:center;font:800 17px/1 var(--body,system-ui);color:#1a1206;background:var(--c,var(--amber,#f5a623));box-shadow:0 0 0 5px color-mix(in srgb,var(--c,var(--amber,#f5a623)) 16%,transparent);flex:none}
.ln-line{position:relative;z-index:1;flex:1;width:2px;margin:4px 0;background:linear-gradient(var(--c,var(--amber,#f5a623)),color-mix(in srgb,var(--c,var(--amber,#f5a623)) 20%,transparent))}
.ln-stage:last-child .ln-line{display:none}
.ln-body{padding:0 0 30px}
.ln-head{display:flex;align-items:baseline;gap:12px;flex-wrap:wrap;margin:6px 0 6px}
.ln-head h2{margin:0;font:800 clamp(20px,3.2vw,26px)/1.2 var(--body,system-ui);letter-spacing:-.01em;color:var(--text,#f2f2f5)}
.ln-head .lv{font:700 11px/1 var(--body,system-ui);letter-spacing:.2em;text-transform:uppercase;color:var(--c,var(--amber,#f5a623))}
.ln-head .dur{margin-left:auto;font:700 12px/1 var(--body,system-ui);color:var(--dim,#7c7c86)}
.ln-desc{margin:0 0 16px;color:var(--muted,#b6b6be);font-size:15px;max-width:680px}
/* 该阶段的资源卡 */
.ln-cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px}
.ln-card{display:flex;flex-direction:column;gap:8px;padding:15px 16px;text-decoration:none;color:inherit;border-radius:13px;background:var(--card,rgba(255,255,255,.035));border:1px solid var(--line,rgba(255,255,255,.08));border-left:3px solid transparent;transition:transform .24s ease,border-color .24s ease,background .24s ease}
.ln-card__main{display:flex;flex:1;flex-direction:column;gap:8px;text-decoration:none;color:inherit}
.ln-card:hover{transform:translateX(4px);border-left-color:var(--c,var(--amber,#f5a623));background:color-mix(in srgb,var(--card,rgba(255,255,255,.05)) 72%,var(--c,var(--amber,#f5a623)) 5%)}
.ln-card__k{font:700 11px/1 var(--body,system-ui);letter-spacing:.12em;text-transform:uppercase;color:var(--dim,#7c7c86)}
.ln-card__t{font:800 15.5px/1.3 var(--body,system-ui);color:var(--text,#f2f2f5)}
.ln-card__d{font:400 13px/1.55 var(--body,system-ui);color:var(--muted,#a6a6b0)}
.ln-card__go{margin-top:auto;font:700 12px/1 var(--body,system-ui);color:var(--c,var(--amber,#f5a623));transition:transform .24s ease}
.ln-card:hover .ln-card__go{transform:translateX(4px)}
.ln-card__tools{display:flex;gap:7px;flex-wrap:wrap;padding-top:10px;border-top:1px solid var(--line,rgba(255,255,255,.08))}
.ln-card__tools a{padding:5px 8px;border-radius:7px;text-decoration:none;font:700 11px/1 var(--body,system-ui);color:var(--c,var(--amber,#f5a623));background:color-mix(in srgb,var(--c,var(--amber,#f5a623)) 9%,transparent);border:1px solid color-mix(in srgb,var(--c,var(--amber,#f5a623)) 24%,transparent)}
.ln-card__tools a:hover{border-color:var(--c,var(--amber,#f5a623))}
.learn-root .reveal{opacity:0;transform:translateY(16px);transition:opacity .6s ease,transform .6s ease}
.learn-root .reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.learn-root .reveal{opacity:1;transform:none;transition:none}.ln-card,.ln-card__go{transition:none}}
@media (max-width:560px){.ln-stage{grid-template-columns:48px 1fr;gap:0 14px}.ln-dot{width:38px;height:38px;font-size:15px}.ln-head .dur{margin-left:0;width:100%}}