/* Μαθητούπολη — κοινό στυλ (landing + παιχνίδι) */
:root{
  --sky:#5ec5f5; --sky-dark:#2a9fd6; --grass:#4cc27a; --grass-dark:#2f9c5b;
  --sun:#ffc23c; --coral:#ff6b6b; --violet:#8b5cf6;
  --ink:#1f2a44; --ink-soft:#5b6884; --paper:#ffffff; --cream:#fdf6e9;
  --ok:#22b573; --bad:#ef4444;
  --r:20px; --shadow:0 10px 30px rgba(31,42,68,.14);
  --font:'Nunito','Segoe UI',Calibri,Arial,sans-serif;
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{margin:0;padding:0}
body{
  font-family:var(--font); color:var(--ink); background:var(--cream);
  font-size:17px; line-height:1.55; -webkit-font-smoothing:antialiased;
}
h1,h2,h3{line-height:1.2;margin:0 0 .5em}
a{color:var(--sky-dark)}
button{font-family:inherit;font-weight:800;cursor:pointer;border:0}

/* ---------- Κουμπιά ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.5em;
  padding:16px 28px;border-radius:999px;font-size:1.05rem;font-weight:800;
  background:var(--sun);color:#4a3200;box-shadow:0 5px 0 #d99a12;
  transition:transform .08s, box-shadow .08s; text-decoration:none;
}
.btn:active{transform:translateY(4px);box-shadow:0 1px 0 #d99a12}
.btn-green{background:var(--grass);color:#fff;box-shadow:0 5px 0 var(--grass-dark)}
.btn-green:active{box-shadow:0 1px 0 var(--grass-dark)}
.btn-blue{background:var(--sky);color:#fff;box-shadow:0 5px 0 var(--sky-dark)}
.btn-blue:active{box-shadow:0 1px 0 var(--sky-dark)}
.btn-ghost{background:#fff;color:var(--ink);box-shadow:0 5px 0 #d9dee9}
.btn-ghost:active{box-shadow:0 1px 0 #d9dee9}
.btn-sm{padding:10px 18px;font-size:.92rem}

/* ---------- Landing ---------- */
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}
.nav{display:flex;align-items:center;justify-content:space-between;padding:18px 0}
.logo{display:flex;align-items:center;gap:10px;font-weight:900;font-size:1.25rem;text-decoration:none;color:var(--ink)}
.logo .mark{width:42px;height:42px;border-radius:13px;background:linear-gradient(140deg,var(--sun),var(--coral));
  display:grid;place-items:center;font-size:1.3rem;box-shadow:var(--shadow)}
.hero{
  background:linear-gradient(180deg,var(--sky) 0%,#9fdcfb 62%,var(--cream) 100%);
  padding-bottom:70px;position:relative;overflow:hidden
}
.hero .wrap{position:relative;z-index:2}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:40px;align-items:center;padding:30px 0 10px}
.hero h1{font-size:clamp(2rem,5vw,3.2rem);color:#fff;text-shadow:0 3px 0 rgba(0,0,0,.12)}
.hero p.lead{font-size:1.15rem;color:#12384d;max-width:36ch;margin-bottom:26px}
.hero-cta{display:flex;gap:14px;flex-wrap:wrap}
.hero-art{background:#fff;border-radius:28px;box-shadow:var(--shadow);padding:18px;transform:rotate(-1.5deg)}
.cloud{position:absolute;background:#fff;border-radius:999px;opacity:.75;filter:blur(.3px)}
.card{background:var(--paper);border-radius:var(--r);box-shadow:var(--shadow);padding:26px}
.section{padding:56px 0}
.section h2{font-size:clamp(1.5rem,3.4vw,2.1rem);text-align:center}
.section .sub{text-align:center;color:var(--ink-soft);max-width:60ch;margin:0 auto 34px}
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.feat{text-align:center}
.feat .ico{font-size:2.4rem;display:block;margin-bottom:8px}
.grades{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.grade-card{background:#fff;border-radius:var(--r);box-shadow:var(--shadow);padding:20px;text-align:center;
  border-top:6px solid var(--sky);text-decoration:none;color:inherit;display:block}
.grade-card.soon{opacity:.62}
.grade-card .g-n{font-size:2rem;font-weight:900;color:var(--sky-dark)}
.tag{display:inline-block;font-size:.72rem;font-weight:800;padding:3px 10px;border-radius:999px;background:#e8f7ef;color:var(--ok)}
.tag.grey{background:#eef0f5;color:var(--ink-soft)}
.price-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;align-items:stretch}
.price{background:#fff;border-radius:var(--r);box-shadow:var(--shadow);padding:26px;text-align:center;display:flex;flex-direction:column}
.price.best{border:3px solid var(--sun);position:relative}
.price.best::before{content:'ΚΑΛΥΤΕΡΗ ΑΞΙΑ';position:absolute;top:-13px;left:50%;transform:translateX(-50%);
  background:var(--sun);color:#4a3200;font-size:.68rem;font-weight:900;padding:4px 14px;border-radius:999px;white-space:nowrap}
.price .amt{font-size:2.4rem;font-weight:900}
.price .amt small{font-size:.9rem;color:var(--ink-soft);font-weight:700}
.price ul{list-style:none;padding:0;margin:18px 0;text-align:left;flex:1}
.price li{padding:6px 0 6px 26px;position:relative}
.price li::before{content:'✓';position:absolute;left:0;color:var(--ok);font-weight:900}
footer{background:#1f2a44;color:#c6cfe0;padding:34px 0;margin-top:30px;font-size:.92rem}
footer a{color:#9fdcfb}
@media(max-width:860px){
  .hero-grid,.grid-3,.price-grid{grid-template-columns:1fr}
  .grades{grid-template-columns:repeat(2,1fr)}
  .hero-art{transform:none}
}

.btn:disabled,.btn[disabled]{opacity:.45;box-shadow:none;transform:none;cursor:default}