.site-header{position:sticky;top:0;z-index:100;background:var(--surface);border-bottom:1px solid var(--border)}.header-inner{width:min(1400px,calc(100% - 40px));margin:auto;position:relative}.header-top{min-height:58px;display:flex;align-items:center;gap:18px}.logo{display:flex;align-items:center;gap:8px;font-size:18px;font-weight:850;color:var(--text);white-space:nowrap;flex:0 0 auto}.logo-mark{display:grid;place-items:center;width:30px;height:30px;border-radius:8px;background:var(--primary);color:#fff;font-size:20px;line-height:1}.header-actions{margin-left:auto;display:grid;grid-template-columns:auto auto minmax(180px,380px) 34px 34px;align-items:center;gap:8px;min-width:0}.login-link,.register-link{font-weight:700;color:var(--text);white-space:nowrap;padding:7px 10px;border-radius:8px;background:var(--surface2);border:1px solid var(--border)}.login-link:hover,.register-link:hover{background:var(--surface);color:var(--primary);border-color:var(--primary)}.search-box{display:flex;width:100%;background:var(--surface2);border:1px solid var(--border);border-radius:8px;overflow:hidden}.search-box input{width:100%;height:34px;padding:0 10px;border:0;background:transparent;color:var(--text);outline:none;min-width:0}.search-box button{height:34px;width:44px;flex:0 0 44px;border:0;border-left:1px solid var(--border);background:transparent;color:var(--text)}.theme-button{width:34px;height:34px;flex:0 0 34px;border:1px solid var(--border);border-radius:8px;background:var(--surface);color:var(--text);cursor:pointer}.upload-link{width:34px;height:34px;flex:0 0 34px;border-radius:8px!important;background:var(--primary)!important;color:#fff!important;display:grid;place-items:center;font-size:22px}.main-nav{height:44px;display:flex;align-items:stretch;overflow-x:auto;overflow-y:hidden;scrollbar-width:none}.main-nav::-webkit-scrollbar{display:none}.main-nav a{flex:1 1 0;min-width:0;display:flex;justify-content:center;align-items:center;padding:0 10px;color:var(--muted);font-weight:700;white-space:nowrap;border-bottom:2px solid transparent}.main-nav a:hover{color:var(--primary);background:var(--surface2)}.main-nav .menu-button{flex:0 0 40px;align-self:center;width:34px;height:34px;margin-left:4px;display:grid;place-content:center;gap:4px;border:1px solid var(--border);border-radius:8px;background:var(--surface);color:var(--text);cursor:pointer}.menu-button span{width:17px;height:2px;border-radius:2px;background:currentColor}.section-menu{position:absolute;right:0;top:102px;width:210px;padding:12px;background:var(--surface);border:1px solid var(--border);border-radius:12px;box-shadow:var(--shadow);z-index:110}.section-menu strong{display:block;padding:4px 10px 8px}.section-menu a{display:block;padding:10px;border-radius:8px;color:var(--text)}.section-menu a:hover{background:var(--surface2);color:var(--primary)}@media(max-width:900px){.header-inner{width:calc(100% - 24px)}.header-top{gap:10px}.header-actions{grid-template-columns:auto auto minmax(140px,280px) 34px 34px;gap:5px}.search-box{min-width:0}}@media(max-width:680px){.header-inner{width:calc(100% - 16px)}.header-top{min-height:54px;gap:7px}.logo>span:last-child{display:none}.logo-mark{width:28px;height:28px;font-size:19px}.header-actions{grid-template-columns:auto auto minmax(70px,1fr) 32px 32px;gap:4px;flex:1}.login-link,.register-link{font-size:13px;padding:6px 7px}.search-box{width:100%;min-width:0}.search-box input{height:32px;padding:0 7px}.search-box button{height:32px;width:36px;flex-basis:36px;font-size:0}.search-box button::before{content:'⌕';font-size:16px}.theme-button,.upload-link{width:32px;height:32px;flex-basis:32px}.upload-link{font-size:20px}.main-nav{height:42px}.main-nav a{flex:0 0 20%;padding:0 4px;font-size:14px}.main-nav .menu-button{flex-basis:36px;width:32px;height:32px;margin-left:2px}.section-menu{top:96px}}@media(max-width:390px){.header-top{gap:5px}.header-actions{grid-template-columns:auto auto minmax(54px,1fr) 30px 30px;gap:3px}.login-link,.register-link{font-size:12px;padding:6px 5px}.theme-button,.upload-link{width:30px;height:30px;flex-basis:30px}.main-nav a{font-size:13px}}