/* ================= ROOT VARIABLES ================= */
:root {
  --brand:#2d6cdf;
  --brand-dark:#1d4ed8;
  --ink:#4b0082;
  --text:#0b1020;
  --gray:#333;
  --bg:#f7f8fb;

  --radius:14px;
  --shadow:0 10px 35px rgba(0,0,0,0.25);
  --transition:.25s ease;
}

/* ================= BASE ================= */
* {box-sizing:border-box; margin:0; padding:0;}
body {
  font-family:"Segoe UI","Noto Sans KR",sans-serif;
  background:var(--bg); color:var(--text); line-height:1.6;
}
a {text-decoration:none; color:var(--gray); transition:var(--transition);}
a:hover {color:var(--brand);}

main {padding-top:68px;}

/* ================= HEADER ================= */
header {
  position:fixed; inset:0 0 auto 0; height:68px;
  z-index:50; padding:0 24px;
  background:rgba(255,255,255,.8);
  backdrop-filter:blur(10px);
  border-bottom:1px solid rgba(0,0,0,.05);
  display:flex; justify-content:space-between; align-items:center;
}
.brand {font-size:22px; font-weight:700; color:var(--ink);}

nav {display:flex; align-items:center; gap:16px;}
nav a {font-size:15px; font-weight:500;}

.nav-cta {
  background:var(--brand); color:#fff!important;
  padding:8px 16px; border-radius:999px; font-weight:600;
  box-shadow:0 4px 10px rgba(45,108,223,0.3);
}
.nav-cta:hover {background:var(--brand-dark); transform:translateY(-2px);}

/* HAMBURGER */
.menu-toggle {
  display:none; width:32px; height:32px;
  flex-direction:column; justify-content:center;
  background:none; border:none; cursor:pointer;
}
.menu-toggle span {
  height:3px; width:24px; background:#333; margin:4px 0;
  border-radius:2px; transition:var(--transition);
}
.menu-toggle.active span:nth-child(1){transform:rotate(45deg) translateY(7px);}
.menu-toggle.active span:nth-child(2){opacity:0;}
.menu-toggle.active span:nth-child(3){transform:rotate(-45deg) translateY(-7px);}

/* ================= HERO ================= */
.hero {
  text-align:center; color:#fff; padding:140px 20px;
  background:linear-gradient(180deg,rgba(8,16,28,.55),rgba(8,16,28,.35)),
             url('/img/bg_new.png') center/cover no-repeat;
}
.hero h1 {font-size:42px; font-weight:800; margin-bottom:20px;}
.hero p {font-size:17px; opacity:.9;}
.hero .btn-primary {margin-top:30px;}

/* ================= MATH SECTION ================= */
.math-section {
  text-align:center; padding:120px 20px 100px; position:relative;
  background:linear-gradient(180deg,rgba(255,255,255,0.92),rgba(245,245,250,0.96)),
             url('/img/math_bg_light.jpg') center/cover no-repeat;
  overflow:hidden;
}
.math-section h1 {font-size:42px; font-weight:800; color:var(--ink);}
.math-section p {font-size:17px; margin-bottom:30px;}
.math-section .btn-primary {background:var(--ink);}
.math-section .btn-primary:hover {background:#3a006a;}

/* Floating Symbols */
.math-symbols {position:absolute; inset:0; overflow:hidden; pointer-events:none;}
.math-symbol {
  position:absolute; font-size:32px; font-weight:700;
  color:rgba(75,0,130,0.15); animation:floatSymbol 12s linear infinite;
}
@keyframes floatSymbol {
  0% {transform:translateY(0) rotate(0); opacity:.3;}
  50% {opacity:.6;}
  100% {transform:translateY(-120vh) rotate(360deg); opacity:0;}
}

/* ================= WING ================= */
.side-wing {
  position:fixed; right:0; top:45%; transform:translateY(-50%);
  display:flex; flex-direction:column; gap:10px; z-index:99;
}
.side-wing a {
  background:var(--brand); color:#fff;
  padding:10px 16px; border-radius:8px 0 0 8px;
  font-size:14px; font-weight:600; box-shadow:var(--shadow);
  transform:translateX(100px); opacity:.8; transition:var(--transition);
}
.side-wing a:hover {transform:translateX(0); opacity:1;}

.side-tip {
  position:fixed; right:200px; top:45%; transform:translateY(-50%);
  background:#1e3a8a; color:#fff;
  padding:10px 16px; border-radius:10px; font-size:13px;
  box-shadow:0 3px 10px rgba(0,0,0,.25); z-index:100;
  animation:tipSlide .8s forwards;
}
@keyframes tipSlide {0%{opacity:0;transform:translate(40px,-50%);}100%{opacity:1;transform:translate(0,-50%);}}

/* ================= POPUP ================= */
.popup-overlay {
  position:fixed; inset:0; display:none; align-items:center; justify-content:center;
  background:rgba(0,0,0,.45); z-index:9999;
}
.popup-overlay.active {display:flex;}

.popup-box {
  width:580px; max-width:95%; background:#fff;
  border-radius:var(--radius); padding:28px; text-align:center;
  border:2px solid #dce3f3; box-shadow:var(--shadow);
  animation:popupFade .3s ease-out;
}
@keyframes popupFade {
  from {opacity:0; transform:scale(.92) translateY(-10px);}
  to   {opacity:1; transform:scale(1) translateY(0);}
}

/* Math popup override */
#mathPopup .popup-box {width:1100px;}
#mathPopup iframe {height:88vh !important;}

/* ================= FAMILY SITES ================= */
.family-sites {
  text-align:center; padding:60px 20px 40px;
  background:linear-gradient(140deg,#eef2ff,#ffffff);
  border-top:1px solid #e5e7eb;
}
.family-sites h3 {font-size:24px; font-weight:800; color:#1e3a8a; margin-bottom:28px;}
.family-grid {display:flex; flex-wrap:wrap; justify-content:center; gap:28px;}

.site-card {
  width:140px; padding:20px 18px; border-radius:14px;
  display:flex; flex-direction:column; align-items:center;
  background:#fff; border:1px solid #e2e8f0; box-shadow:0 6px 18px rgba(0,0,0,.08);
  transition:var(--transition);
}
.site-card:hover {transform:translateY(-6px); box-shadow:0 12px 24px rgba(0,0,0,.14);}
.site-logo {width:64px; height:64px; border-radius:18px; display:flex; align-items:center; justify-content:center; font-size:32px; font-weight:800; color:#fff; margin-bottom:12px;}
.site-logo.hd {background:#b91c1c;}
.site-logo.vb {background:#2563eb;}
.site-card span {font-size:15px; font-weight:600; color:#1e3a8a;}

/* ================= FOOTER ================= */
footer {
  text-align:center; padding:30px; font-size:14px; color:#444;
  background:linear-gradient(120deg,rgba(11,97,194,.1),rgba(234,244,255,.3));
}

/* ================= RESPONSIVE ================= */
@media (max-width:768px){
  nav {position:absolute; top:68px; left:0; right:0; flex-direction:column; max-height:0; overflow:hidden;
       background:rgba(255,255,255,.95); transition:max-height .3s ease;}
  nav.open {max-height:380px; border-bottom:1px solid rgba(0,0,0,.05);}
  nav a {padding:14px 0; width:100%; text-align:center; border-top:1px solid rgba(0,0,0,0.05);}
  .menu-toggle {display:flex;}

  .side-tip {display:none;}
  .side-wing {top:auto; bottom:calc(16px + env(safe-area-inset-bottom)); right:6px; transform:none;}
  .side-wing a {transform:translateX(0); opacity:.95;}

  #eventPopup .popup-box {
    width:100%; max-width:100%; border-radius:18px 18px 0 0;
    position:absolute; bottom:0; left:0; padding:20px;
    transform:translateY(100%); animation:slideUp .35s ease forwards;
  }
  @keyframes slideUp {from{transform:translateY(100%);}to{transform:translateY(0);} }
}

/* ================= POPUP INNER ELEMENTS ================= */
.popup-header h2 {
  font-size:22px;
  font-weight:800;
  margin-bottom:18px;
  color:#002b5c;
}

.highlight {
  font-size:15px;
  line-height:1.8;
  color:#333;
  background:#f3f6ff;
  padding:18px 20px;
  border-left:4px solid var(--brand);
  border-radius:10px;
  margin:24px 0;
  text-align:left;
}

.popup-actions {
  margin-top:26px;
  display:flex;
  justify-content:center;
  gap:12px;
}

/* Action Buttons */
.btn-go, .btn-close {
  padding:10px 24px;
  border-radius:8px;
  font-size:15px;
  font-weight:700;
  cursor:pointer;
  transition:var(--transition);
  border:none;
}

.btn-go {
  background:var(--brand);
  color:#fff;
  box-shadow:0 4px 12px rgba(45,108,223,0.35);
}
.btn-go:hover { background:var(--brand-dark); transform:translateY(-2px); }

.btn-close {
  background:#6b7280;
  color:#fff;
}
.btn-close:hover { background:#4b5563; transform:translateY(-2px); }

/* mobile sheet handle */
.popup-handle {
  width:48px;
  height:5px;
  border-radius:4px;
  background:#cbd5e1;
  margin:0 auto 14px auto;
}
#popupTodayClose {
  background:#374151;
}
#popupTodayClose:hover {
  background:#1f2937;
}

/* ================= ROUNDED RECTANGLE BUTTON ================= */
.btn {
  display:inline-block;
  padding:14px 36px;
  border-radius:12px;  /* ← 딱 적당히 둥근 사각형 */
  font-weight:700;
  font-size:17px;
  text-align:center;
  cursor:pointer;
  transition:all .25s ease;
  background:#3a006a;
  border:2px solid var(--ink);
  color:#ffffff;
  box-shadow:0 6px 14px rgba(0,0,0,0.08);
}

.btn:hover {
  background:var(--ink);
  color:#fff;
  transform:translateY(-3px);
  box-shadow:0 10px 22px rgba(75,0,130,0.28);
}

/* 강조 CTA 버튼 */
.btn-primary {
  background:var(--ink);
  color:#fff;
  border:2px solid var(--ink);
  box-shadow:0 8px 20px rgba(75,0,130,0.35);
}

.btn-primary:hover {
  background:#3a006a;
  transform:translateY(-3px);
}

/* 정렬 */
.btn-wrap {
  display:flex;
  justify-content:center;
  gap:20px;
  margin-top:24px;
}