/* 首页电话常驻固定页眉，手机保留完整号码。 */
.nav .header-phone{margin-left:auto;flex:none;color:#aaff00;font-family:"Poppins",sans-serif;font-size:18px;font-weight:600;letter-spacing:0;line-height:1.4;white-space:nowrap;padding:12px 0;text-decoration:none}
.nav .header-phone:hover{text-decoration:underline;text-underline-offset:5px}
@media(min-width:1001px) and (max-width:1200px){.nav>.wrap{width:calc(100% - 48px)}.nav .brand{font-size:20px}.nav .menu{gap:18px}.nav .menu a{font-size:14px}.nav .header-phone{font-size:15px}}
@media(max-width:1000px){.nav>.wrap{gap:16px}.nav .header-phone{order:1;font-size:15px}.nav .menu-btn{order:2;margin-left:0;flex:none}}
@media(max-width:600px){.nav,.nav>.wrap{height:92px}.nav>.wrap{display:grid;grid-template-columns:1fr 44px;grid-template-rows:46px 38px;column-gap:12px;row-gap:0;align-content:center}.nav>.wrap>a:first-child{grid-column:1;grid-row:1}.nav .header-phone{grid-column:1;grid-row:2;margin:0;padding:6px 0;justify-self:start;font-size:17px}.nav .menu-btn{grid-column:2;grid-row:1 / 3}.nav .menu{top:92px}.hero:has(#opening-video) .top{top:116px}.hero:has(#opening-video) .motion-toggle{top:110px}.hero:has(#opening-video) .frame{padding-top:204px}}
/* 中等桌面宽度也限制内容容器，避免旧固定宽度产生横向滚动。 */
.work-section .wrap,.foot .wrap{max-width:calc(100% - 40px)}

.nav{position:fixed;top:0;left:0;right:0}
body.classroom-page{padding-top:76px}@media(max-width:1000px){body.classroom-page{padding-top:68px}}@media(max-width:600px){body.classroom-page{padding-top:92px}}