header{background:var(--header-bg);color:var(--header-text);padding:0.8rem 1rem;display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:1rem;}.site-title{font-size:1.5rem;font-weight:bold;color:white;text-decoration:none;}nav a{color:white;margin:0 0.9rem;text-decoration:none;font-weight:500;}nav a:hover{text-decoration:underline;}.theme-toggle{background:rgba(255,255,255,0.25);border:none;color:white;padding:0.5rem 0.9rem;border-radius:999px;cursor:pointer;font-size:0.95rem;}.theme-toggle:hover{background:rgba(255,255,255,0.4);}.site-intro{background:var(--card-bg);border:1px solid var(--border);border-radius:8px;padding:1.5rem;margin-bottom:2.5rem;}.site-intro h3{margin-bottom:0.8rem;color:var(--accent);font-size:1.3rem;}.intro-body{position:relative;max-height:160px;overflow:hidden;line-height:1.7;transition:max-height 0.45s cubic-bezier(0.4,0,0.2,1);}.intro-fade{position:absolute;left:0;right:0;bottom:0;height:56px;background:linear-gradient(to bottom,transparent,var(--card-bg) 75%);pointer-events:none;opacity:1;transition:opacity 0.3s ease;}.intro-body.expanded .intro-fade{opacity:0;}.intro-toggle-wrap{text-align:center;margin-top:1rem;}.intro-toggle-btn{display:inline-flex;align-items:center;gap:0.35rem;padding:0.5rem 1.3rem;background:var(--accent);color:#fff;border:none;border-radius:999px;cursor:pointer;font-size:0.9rem;font-weight:600;transition:background 0.2s,transform 0.15s;}.intro-toggle-btn:hover{background:var(--accent-dark);}.intro-toggle-btn:active{transform:scale(0.96);}.intro-toggle-icon{display:inline-block;transition:transform 0.3s ease;}.intro-toggle-btn[aria-expanded="true"] .intro-toggle-icon{transform:rotate(180deg);}@media (max-width:768px){.intro-body{max-height:140px;}.site-intro{padding:1rem;}}@media (max-width:768px){header{padding:0.6rem 0.5rem;flex-direction:column;gap:0.8rem;align-items:flex-start;}.site-title{width:100%;text-align:left;font-size:1.3rem;}nav{width:100%;font-size:0.85rem;display:flex;flex-wrap:wrap;gap:0.5rem 0.8rem;}nav a{margin:0;}.theme-toggle{align-self:flex-end;margin-top:-2.8rem;padding:0.4rem 0.7rem;font-size:0.85rem;}}@media (max-width:480px){header{padding:0.5rem 0.4rem;}.theme-toggle{margin-top:-2.5rem;padding:0.3rem 0.6rem;font-size:0.8rem;}.site-intro{padding:0.8rem;}}
/* 移动端把站名与模式按钮固定在首行，导航在次行横向触控滚动，避免菜单与按钮相互覆盖。 */
@media (max-width:768px){
header{display:grid;grid-template-columns:minmax(0,1fr) auto;flex-direction:initial;align-items:center;gap:.65rem .75rem;padding:.65rem .75rem;}
.site-title{grid-column:1;grid-row:1;width:auto;min-width:0;max-width:100%;text-align:left;font-size:1.2rem;line-height:1.2;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
header>nav{grid-column:1/-1;grid-row:2;width:100%;display:flex;flex-wrap:nowrap;align-items:center;gap:.85rem;overflow-x:auto;overflow-y:hidden;padding:.1rem 0 .15rem;scrollbar-width:none;-webkit-overflow-scrolling:touch;}
header>nav::-webkit-scrollbar{display:none;}
header>nav a{flex:0 0 auto;margin:0;white-space:nowrap;font-size:.82rem;}
header>nav .header-menu-list{flex-wrap:nowrap;gap:.85rem;width:max-content;min-width:100%;}
.theme-toggle{grid-column:2;grid-row:1;align-self:center;margin:0;padding:.38rem .7rem;font-size:.8rem;line-height:1.2;white-space:nowrap;}
}