/* Aquamarine Academy — static site styles */
:root{
  --aqua-900:#0b3a47; --aqua-700:#0e6b7e; --aqua-600:#108a9c; --aqua-500:#16a3b8;
  --aqua-400:#39bccf; --aqua-200:#a8e3ec; --aqua-50:#eef9fb;
  --ink:#16242a; --muted:#5a6b72; --line:#dce8eb; --white:#fff;
  --shadow:0 6px 24px rgba(11,58,71,.10); --radius:14px; --maxw:1080px;
  --font:"Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:var(--font);color:var(--ink);background:var(--white);line-height:1.65;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:var(--aqua-700);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3{line-height:1.2;color:var(--aqua-900);margin:0 0 .5em}
h1{font-size:clamp(2rem,4vw,2.9rem);font-weight:800;letter-spacing:-.02em}
h2{font-size:clamp(1.5rem,3vw,2rem);font-weight:700}
h3{font-size:1.2rem;font-weight:700}
.container{max-width:var(--maxw);margin:0 auto;padding:0 20px}
.section{padding:64px 0}
.section--tight{padding:44px 0}
.lead{font-size:1.15rem;color:var(--muted)}

/* Header / nav */
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.nav{display:flex;align-items:center;justify-content:space-between;height:68px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;color:var(--aqua-900);font-size:1.15rem}
.brand:hover{text-decoration:none}
.brand .dot{width:28px;height:28px;border-radius:8px;background:linear-gradient(135deg,var(--aqua-400),var(--aqua-700));display:inline-block}
.nav-links{display:flex;gap:6px;align-items:center;list-style:none;margin:0;padding:0}
.nav-links a{display:inline-block;padding:9px 14px;border-radius:9px;color:var(--ink);font-weight:500}
.nav-links a:hover{background:var(--aqua-50);text-decoration:none}
.nav-links a.active{color:var(--aqua-700);background:var(--aqua-50)}
.nav-toggle{display:none;background:none;border:0;cursor:pointer;padding:8px}
.nav-toggle span{display:block;width:24px;height:2px;background:var(--aqua-900);margin:5px 0;transition:.25s}

/* Hero */
.hero{background:linear-gradient(160deg,var(--aqua-50),#fff 60%);border-bottom:1px solid var(--line)}
.hero-inner{padding:72px 0 64px;max-width:760px}
.hero .eyebrow{color:var(--aqua-600);font-weight:700;letter-spacing:.08em;text-transform:uppercase;font-size:.8rem;margin-bottom:14px}
.hero p{font-size:1.18rem;color:var(--muted);margin:18px 0 28px}

/* Buttons */
.btn{display:inline-block;padding:13px 24px;border-radius:10px;font-weight:600;cursor:pointer;border:1px solid transparent;transition:.2s}
.btn-primary{background:var(--aqua-700);color:#fff}
.btn-primary:hover{background:var(--aqua-900);text-decoration:none}
.btn-ghost{background:#fff;color:var(--aqua-700);border-color:var(--line)}
.btn-ghost:hover{border-color:var(--aqua-400);text-decoration:none}
.btn-row{display:flex;gap:12px;flex-wrap:wrap}

/* Cards / features */
.grid{display:grid;gap:22px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:1.4fr 1fr}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow)}
.card h3{margin-top:0}
.card .ico{width:44px;height:44px;border-radius:10px;background:var(--aqua-50);color:var(--aqua-700);display:flex;align-items:center;justify-content:center;font-size:1.4rem;margin-bottom:14px}

/* Courses */
.term{border:1px solid var(--line);border-radius:var(--radius);padding:20px 24px;margin-bottom:16px;background:#fff;box-shadow:var(--shadow)}
.term h3{margin:0 0 8px;color:var(--aqua-700);font-size:1.05rem}
.term ul{margin:0;padding-left:18px}
.term li{margin:4px 0}
.badge{display:inline-block;background:var(--aqua-50);color:var(--aqua-700);font-size:.78rem;font-weight:600;padding:2px 9px;border-radius:999px;margin-left:6px}

/* Teacher */
.profile{display:grid;grid-template-columns:220px 1fr;gap:34px;align-items:start}
.profile img{border-radius:var(--radius);box-shadow:var(--shadow);width:220px;height:auto}

/* PDF embed */
.pdf-frame{width:100%;height:780px;border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);background:#fff}

/* Forms */
.form{max-width:560px}
.field{margin-bottom:18px}
.field label{display:block;font-weight:600;margin-bottom:6px}
.field input,.field textarea{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:10px;font:inherit;background:#fff}
.field input:focus,.field textarea:focus{outline:2px solid var(--aqua-400);border-color:transparent}
.field textarea{min-height:150px;resize:vertical}
.hp{position:absolute;left:-5000px}
.notice{padding:14px 16px;border-radius:10px;margin-bottom:20px;font-weight:500}
.notice-ok{background:#e7f7ee;color:#16623a;border:1px solid #b9e6cd}
.notice-err{background:#fdecec;color:#8a2020;border:1px solid #f3c2c2}

/* Footer */
.site-footer{background:var(--aqua-900);color:#cfe8ee;padding:44px 0;margin-top:24px}
.site-footer a{color:#fff}
.foot-grid{display:flex;justify-content:space-between;flex-wrap:wrap;gap:20px}
.site-footer h4{color:#fff;margin:0 0 10px;font-size:1rem}
.muted-light{color:#9fcdd7;font-size:.9rem}

/* Responsive */
@media(max-width:820px){
  .grid-3{grid-template-columns:1fr}
  .grid-2{grid-template-columns:1fr}
  .profile{grid-template-columns:1fr;justify-items:start}
  .nav-toggle{display:block}
  .nav-links{position:absolute;top:68px;left:0;right:0;flex-direction:column;align-items:stretch;gap:0;background:#fff;border-bottom:1px solid var(--line);padding:8px 12px;display:none}
  .nav-links.open{display:flex}
  .nav-links a{padding:12px}
}

/* Imported course content (self-hosted from former WeChat articles) */
.course-hd{border-bottom:1px solid var(--line);padding-bottom:18px;margin-bottom:8px}
.course-hd .term-tag{color:var(--aqua-600);font-weight:700;text-transform:uppercase;letter-spacing:.06em;font-size:.8rem}
.wx-content{max-width:720px;margin:0 auto}
.wx-content img{max-width:100%;height:auto;display:block;margin:14px auto;border-radius:8px}
.wx-content p,.wx-content section{margin:0 0 14px}
.wx-content *{max-width:100%!important;box-sizing:border-box}
.back-link{display:inline-block;margin:24px 0 0;font-weight:600}