/* 课程介绍页（1V1 / 中教小班课）共用样式 */
:root{
 --bg:#fff5f9;--card:#fff;--ink:#2b2440;--mute:#7c7194;
 --acc:#2f6bff;--pink:#ff8bb0;--pink-soft:#ffe4ee;--pink-deep:#c2416d;
 --line:#f4dce8;--shadow:0 10px 30px rgba(150,110,200,.13)
}
@media(prefers-color-scheme:dark){:root{--bg:#181327;--card:#221d34;--ink:#f3effc;--mute:#a89ec6;--acc:#8fb0ff;--pink-soft:#3b2438;--pink-deep:#ffb3c9;--line:#372c50}}
*{box-sizing:border-box}
[hidden]{display:none!important}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 -apple-system,"PingFang SC","Microsoft YaHei",sans-serif;
 min-height:100vh;display:flex;flex-direction:column;
 padding:env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left)}
.top{display:flex;align-items:center;gap:10px;padding:12px 14px 6px;position:relative}
.top h1{margin:0;font-size:18px;font-weight:800;color:var(--acc);letter-spacing:.2px}
.top .bk{display:inline-grid;place-items:center;width:34px;height:34px;border-radius:12px;border:1px solid #c3d5fb;
 background:radial-gradient(130% 110% at 50% -30%,#fff 0,rgba(255,255,255,0) 62%),linear-gradient(180deg,#eef4ff,#d9e5ff);
 color:#2b52c4;text-decoration:none;box-shadow:inset 0 1px 0 #fff,0 2px 6px rgba(70,105,220,.16)}
.top .bk svg{width:17px;height:17px}
.top .tag{margin-left:auto;font-size:12px;color:var(--pink-deep);background:var(--pink-soft);border-radius:999px;padding:4px 10px;font-weight:600}
main{flex:1 0 auto;width:100%;max-width:760px;margin:0 auto;padding:6px 14px 24px;display:grid;gap:14px}
.poster{margin:0 auto;max-width:560px;width:100%;background:var(--card);border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow);overflow:hidden;display:grid;place-items:center;min-height:52vh}
.poster img{display:block;width:100%;height:auto}
.poster .ph{text-align:center;color:var(--mute);font-size:14px;padding:56px 24px;line-height:1.9}
.poster .ph b{display:block;font-size:16px;color:var(--pink-deep);margin-bottom:6px}
.lead{margin:0;font-size:15px;color:var(--mute);text-align:center}
.cta{display:flex;gap:10px;flex-wrap:wrap}
.cta button{flex:1 1 150px;padding:13px 16px;border-radius:15px;font-size:15px;font-weight:700;cursor:pointer;border:1px solid transparent;transition:.15s}
.cta .pri{background:var(--acc);color:#fff;box-shadow:0 8px 22px rgba(47,107,255,.28)}
.cta .pri:hover{background:#245ce0}
.cta .ghost{background:var(--card);border-color:var(--line);color:var(--pink-deep)}
.cta .ghost:hover{border-color:#ffc2d6;box-shadow:var(--shadow)}
footer{padding:14px;text-align:center;font-size:12px;color:var(--mute)}
footer a{color:var(--mute);text-decoration:none}
/* 顶栏在手机上收紧 */
@media(max-width:520px){
 .top{padding:10px 12px 4px}
 .top h1{font-size:16px}
 main{padding:4px 12px 20px;gap:12px}
 .poster{min-height:46vh;border-radius:16px}
}