:root{
  --primary:#4db8a4;
  --primary-dark:#3a9e8c;
  --primary-light:#6fcfbe;
  --accent:#45a899;
  --accent-light:#a8e6db;
  --danger:#e8564a;
  --warning:#d98900;
  --gradient-main:linear-gradient(135deg,#4db8a4,#5ec6b4);
  --gradient-soft:linear-gradient(135deg,#4db8a4 0%,#5ec6b4 50%,#7dd4c6 100%);
  --gradient-header:linear-gradient(135deg,#4db8a4,#5ec6b4,#7dd4c6);
  --bg-page:#f6f8fa;
  --bg-white:#ffffff;
  --bg-gray-50:#f8f9fb;
  --bg-gray-100:#f0f2f5;
  --bg-green-50:#edf9f5;
  --bg-teal-50:#f0faf7;
  --text:#1f2937;
  --text-primary:#1f2937;
  --text-secondary:#4b5563;
  --muted:#4b5563;
  --text-muted:#9ca3af;
  --line:#e5e7eb;
  --border-light:#e5e7eb;
  --border-default:#d1d5db;
  --white:#ffffff;
  --code-bg:#0f172a;
  --code-border:#1f2d45;
  --code-text:#e5eefb;
  --soft-danger-bg:#fef0ef;
  --soft-warning-bg:#fff7ed;
  --shadow:0 1px 3px rgba(0,0,0,.05),0 1px 2px rgba(0,0,0,.03);
  --shadow-hover:0 4px 12px rgba(77,184,164,.12),0 2px 4px rgba(0,0,0,.04);
  --shadow-card:0 1px 3px rgba(0,0,0,.05),0 1px 2px rgba(0,0,0,.03);
  --shadow-card-hover:0 4px 12px rgba(77,184,164,.12),0 2px 4px rgba(0,0,0,.04);
  --press-shadow:0 1px 2px rgba(0,0,0,.05);
  --radius-sm:6px;
  --radius-md:10px;
  --radius-lg:12px;
  --radius-xl:16px;
  /* legacy index aliases retained here so old hardcoded roots are removed cleanly. */
  --mint:#4db8a4;
  --mint2:#6fcfbe;
  --cream:#fff7df;
  --cream2:#fffdf4;
  --soft:#fff7ed;
  --pink:#fef0ef;
  --pink-text:#e8564a;
  --blue:#3a9e8c;
  --blue2:#4db8a4;
}
*{box-sizing:border-box;margin:0;padding:0;}
body{
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei","Segoe UI",sans-serif;
  background:var(--bg-page);
  color:var(--text-primary);
  padding:10px;
}
.page{max-width:1480px;margin:0 auto;}
.tb-cover-head{margin-bottom:12px;}
.hero,.brand-head,.course-intro,.info-card,.outline-card,.outline-btn{
  transition:transform .14s ease, box-shadow .14s ease, background .14s ease, border-color .14s ease;
  will-change:transform;
}
.hero:hover,.brand-head:hover,.course-intro:hover,.info-card:hover,.outline-card:hover,.outline-btn:hover{
  transform:translateY(-1px) scale(.997);
  box-shadow:var(--shadow-card-hover);
}
.hero:active,.brand-head:active,.course-intro:active,.info-card:active,.outline-card:active,.outline-btn:active{
  transform:translateY(2px) scale(.992);
  box-shadow:var(--press-shadow);
}
.hero{
  position:relative;
  overflow:hidden;
  border-radius:24px;
  background:var(--gradient-header);
  padding:20px 26px 18px;
  box-shadow:var(--shadow-card);
  color:#fff;
  border:1px solid rgba(255,255,255,.36);
}
.hero::before{content:"";position:absolute;top:-50%;right:-15%;width:260px;height:260px;background:radial-gradient(circle,rgba(255,255,255,.12) 0%,transparent 70%);border-radius:50%;}
.hero::after{content:"";position:absolute;bottom:-40%;left:-8%;width:180px;height:180px;background:radial-gradient(circle,rgba(255,255,255,.08) 0%,transparent 70%);border-radius:50%;}
.hero-inner{position:relative;z-index:1;display:block;}
.brand-head{
  display:inline-flex;
  flex-direction:row;
  align-items:center;
  gap:10px;
  margin-bottom:10px;
  padding:9px 14px;
  border-radius:14px;
  background:rgba(255,255,255,.92);
  border:1px solid rgba(77,184,164,.22);
  box-shadow:0 4px 12px rgba(77,184,164,.12);
  cursor:pointer;
}
.brand-head::before{content:"知";display:inline-flex;align-items:center;justify-content:center;width:32px;height:32px;border-radius:8px;background:var(--bg-green-50);color:var(--primary-dark);font-weight:900;}
.brand-name{font-size:22px;line-height:1;font-weight:900;letter-spacing:.6px;color:var(--primary-dark);}
.brand-slogan{font-size:13px;line-height:1.1;font-weight:800;color:#4873c7;opacity:1;}
.hero-icon-row{display:flex;justify-content:center;gap:10px;margin:2px auto 8px;}
.fa-local{display:inline-flex;align-items:center;justify-content:center;width:40px;height:40px;border-radius:12px;background:rgba(255,255,255,.94);box-shadow:var(--shadow-card);border:1px solid rgba(255,255,255,.72);}
.fa-local svg{width:29px;height:29px;display:block;}
.hero h1{font-size:28px;line-height:1.34;text-align:center;font-weight:900;letter-spacing:.5px;margin:4px 0 12px;}
.course-intro{max-width:1120px;margin:0 auto;background:rgba(255,255,255,.15);border:1px solid rgba(255,255,255,.22);border-radius:16px;padding:10px 14px;cursor:pointer;}
.course-intro p{font-size:14px;line-height:1.75;text-align:center;color:#ffffff;}
.info-row{margin-top:14px;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;}
.info-card{position:relative;overflow:hidden;background:var(--bg-white);border:1px solid var(--border-light);border-radius:16px;box-shadow:var(--shadow-card);padding:16px 14px 14px;text-align:center;cursor:pointer;min-height:184px;display:flex;flex-direction:column;align-items:center;}
.info-card::after{content:"";position:absolute;right:-28px;top:-28px;width:96px;height:96px;border-radius:50%;background:rgba(77,184,164,.10);}
.info-icon{position:relative;z-index:1;width:44px;height:44px;margin-bottom:10px;display:block;}
.info-icon svg{width:44px;height:44px;display:block;}
.info-title{font-size:17px;font-weight:900;color:var(--primary-dark);margin-bottom:5px;}
.info-badge{display:inline-flex;align-items:center;justify-content:center;min-height:22px;padding:3px 10px;border-radius:999px;background:var(--soft-danger-bg);color:var(--danger);border:1px solid #f6d0cc;font-size:12px;font-weight:900;margin-bottom:8px;}
.info-desc{font-size:13px;line-height:1.58;color:var(--text-secondary);font-weight:700;}
.directory-groups{margin-top:14px;display:flex;flex-direction:column;gap:16px;}
.directory-group{position:relative;overflow:hidden;background:rgba(255,255,255,.72);border:1px solid var(--border-light);border-radius:20px;box-shadow:var(--shadow-card);padding:16px;}
.directory-group::before{content:"";position:absolute;left:0;top:0;bottom:0;width:5px;background:var(--gradient-main);}
.group-head{position:relative;padding:2px 4px 12px 8px;margin-bottom:4px;border-bottom:1px dashed rgba(77,184,164,.28);}
.group-kicker{display:inline-flex;align-items:center;gap:6px;min-height:22px;padding:3px 10px;border-radius:999px;background:var(--bg-green-50);border:1px solid rgba(77,184,164,.18);color:var(--primary-dark);font-size:12px;font-weight:900;margin-bottom:8px;}
.group-head h2{font-size:21px;line-height:1.35;font-weight:900;color:var(--text-primary);margin-bottom:6px;}
.group-benefit{font-size:14px;line-height:1.65;color:var(--text-secondary);font-weight:800;}
.directory-grid{margin-top:12px;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px;}
.group-section-list{grid-template-columns:repeat(3,minmax(0,1fr));}
.outline-card{position:relative;overflow:hidden;display:flex;flex-direction:column;min-height:196px;text-decoration:none;color:inherit;background:var(--bg-white);border:1px solid var(--border-light);border-radius:16px;box-shadow:var(--shadow-card);padding:18px 16px 14px;cursor:pointer;}
.outline-card::before{content:"";position:absolute;left:0;right:0;top:0;height:4px;background:var(--gradient-main);}
.outline-icon{position:absolute;top:16px;right:16px;width:34px;height:34px;border-radius:10px;display:flex;align-items:center;justify-content:center;background:var(--bg-green-50);border:1px solid rgba(77,184,164,.18);font-size:18px;}
.outline-no{width:max-content;min-width:34px;padding:5px 8px;border-radius:10px;background:var(--soft-danger-bg);color:var(--danger);font-size:15px;font-weight:900;line-height:1;margin-bottom:12px;box-shadow:none;}
.outline-title{font-size:15.5px;line-height:1.38;font-weight:900;color:var(--text-primary);min-height:42px;margin-bottom:10px;padding-right:42px;overflow-wrap:anywhere;word-break:break-word;}
.outline-features{list-style:none;margin:0 0 14px 0;padding:0;flex:1;}
.outline-features li{position:relative;padding-left:14px;font-size:14px;line-height:1.55;color:var(--text-secondary);margin:4px 0;font-weight:760;}
.outline-features li::before{content:"▸";position:absolute;left:0;top:0;color:var(--primary);font-weight:900;}
.outline-btn{margin-top:auto;height:34px;border-radius:6px;background:var(--primary);color:#fff;display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:800;cursor:pointer;box-shadow:none;}
.outline-btn:hover{background:var(--primary-dark);}
@media (max-width:1180px){.info-row{grid-template-columns:repeat(2,minmax(0,1fr));}.directory-grid,.group-section-list{grid-template-columns:repeat(2,minmax(0,1fr));}}
@media (max-width:760px){body{padding:8px;}.hero{padding:18px 14px;}.hero h1{font-size:22px;}.hero-icon-row{gap:8px;}.fa-local{width:38px;height:38px;border-radius:10px;}.fa-local svg{width:27px;height:27px;}.info-row{grid-template-columns:1fr;}.directory-group{padding:13px;}.directory-grid,.group-section-list{grid-template-columns:1fr;}}

:root{
  --primary:#4db8a4;
  --primary-dark:#3a9e8c;
  --primary-light:#6fcfbe;
  --accent:#45a899;
  --accent-light:#a8e6db;
  --danger:#e8564a;
  --warning:#d98900;
  --gradient-main:linear-gradient(135deg,#4db8a4,#5ec6b4);
  --gradient-soft:linear-gradient(135deg,#4db8a4 0%,#5ec6b4 50%,#7dd4c6 100%);
  --gradient-header:linear-gradient(135deg,#4db8a4,#5ec6b4,#7dd4c6);
  --bg-page:#f6f8fa;
  --bg-white:#ffffff;
  --bg-gray-50:#f8f9fb;
  --bg-gray-100:#f0f2f5;
  --bg-green-50:#edf9f5;
  --bg-teal-50:#f0faf7;
  --text:#1f2937;
  --text-primary:#1f2937;
  --text-secondary:#4b5563;
  --muted:#4b5563;
  --text-muted:#9ca3af;
  --line:#e5e7eb;
  --border-light:#e5e7eb;
  --border-default:#d1d5db;
  --white:#ffffff;
  --code-bg:#0f172a;
  --code-border:#1f2d45;
  --code-text:#e5eefb;
  --soft-danger-bg:#fef0ef;
  --soft-warning-bg:#fff7ed;
  --shadow:0 1px 3px rgba(0,0,0,.05),0 1px 2px rgba(0,0,0,.03);
  --shadow-hover:0 4px 12px rgba(77,184,164,.12),0 2px 4px rgba(0,0,0,.04);
  --shadow-card:0 1px 3px rgba(0,0,0,.05),0 1px 2px rgba(0,0,0,.03);
  --shadow-card-hover:0 4px 12px rgba(77,184,164,.12),0 2px 4px rgba(0,0,0,.04);
  --press-shadow:0 1px 2px rgba(0,0,0,.05);
  --radius-sm:6px;
  --radius-md:10px;
  --radius-lg:12px;
  --radius-xl:16px;
  /* legacy index aliases retained here so old hardcoded roots are removed cleanly. */
  --mint:#4db8a4;
  --mint2:#6fcfbe;
  --cream:#fff7df;
  --cream2:#fffdf4;
  --soft:#fff7ed;
  --pink:#fef0ef;
  --pink-text:#e8564a;
  --blue:#3a9e8c;
  --blue2:#4db8a4;
}