/* Numbers War III — website. Theme tối + vàng, khớp app icon và giao diện game. */
@import url('https://fonts.googleapis.com/css2?family=Fredoka:wght@400;500;600;700&family=Inter:wght@400;500;600&display=swap');

:root {
  --bg:        #0b0f0d;
  --bg-2:      #111a14;
  --panel:     #16211b;
  --panel-2:   #1d2b22;
  --line:      rgba(255,255,255,.10);
  --gold:      #f5bf3d;
  --gold-soft: #ffd873;
  --blue:      #3b7de6;
  --red:       #e64b4b;
  --text:      #f3f4f0;
  --muted:     #9aa79e;
  --radius:    16px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: radial-gradient(1200px 600px at 50% -10%, #16241b 0%, var(--bg) 55%);
  color: var(--text);
  line-height: 1.65;
  min-height: 100vh;
}

.wrap { max-width: 1000px; margin: 0 auto; padding: 0 22px; }

/* ---- Nav ---- */
header.nav {
  position: sticky; top: 0; z-index: 20;
  backdrop-filter: blur(12px);
  background: rgba(11,15,13,.72);
  border-bottom: 1px solid var(--line);
}
.nav .wrap { display: flex; align-items: center; gap: 14px; height: 62px; }
.brand { display: flex; align-items: center; gap: 11px; font-family: 'Fredoka'; font-weight: 700;
         font-size: 18px; color: var(--text); text-decoration: none; }
.brand img { width: 34px; height: 34px; border-radius: 9px; }
.nav nav { margin-left: auto; display: flex; gap: 6px; }
.nav nav a { color: var(--muted); text-decoration: none; font-weight: 500; font-size: 15px;
             padding: 8px 12px; border-radius: 10px; transition: .15s; }
.nav nav a:hover { color: var(--text); background: rgba(255,255,255,.06); }

/* ---- Buttons ---- */
.btn {
  display: inline-flex; align-items: center; gap: 9px;
  font-family: 'Fredoka'; font-weight: 600; font-size: 16px;
  padding: 13px 22px; border-radius: 13px; text-decoration: none;
  border: 1px solid transparent; cursor: pointer; transition: .15s;
}
.btn-gold { background: var(--gold); color: #21160a; box-shadow: 0 8px 24px -8px rgba(245,191,61,.55); }
.btn-gold:hover { background: var(--gold-soft); transform: translateY(-1px); }
.btn-ghost { background: rgba(255,255,255,.05); color: var(--text); border-color: var(--line); }
.btn-ghost:hover { background: rgba(255,255,255,.10); }

/* ---- Hero ---- */
.hero { text-align: center; padding: 66px 0 40px; }
.hero .logo {
  width: 172px; height: 172px; border-radius: 34px;
  box-shadow: 0 24px 60px -18px rgba(0,0,0,.75), 0 0 0 1px rgba(245,191,61,.35) inset;
  margin-bottom: 26px;
}
.hero h1 {
  font-family: 'Fredoka'; font-weight: 700; letter-spacing: -.5px;
  font-size: clamp(34px, 7vw, 58px); line-height: 1.05;
  background: linear-gradient(180deg, #fff 0%, var(--gold-soft) 130%);
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.hero .tag { color: var(--gold); font-family: 'Fredoka'; font-weight: 500; font-size: clamp(16px,3vw,20px);
             margin-top: 10px; }
.hero p.lead { color: var(--muted); font-size: 17px; max-width: 560px; margin: 18px auto 0; }
.cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 30px; }
.note { color: var(--muted); font-size: 13px; margin-top: 16px; }

/* ---- Sections ---- */
section { padding: 34px 0; }
.h2 { font-family: 'Fredoka'; font-weight: 600; font-size: clamp(24px,5vw,34px); text-align: center; }
.sub { color: var(--muted); text-align: center; margin: 8px auto 30px; max-width: 560px; }

.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px,1fr)); gap: 16px; }
.card {
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border: 1px solid var(--line); border-radius: var(--radius); padding: 24px;
}
.card .ico { font-size: 30px; line-height: 1; margin-bottom: 12px; }
.card h3 { font-family: 'Fredoka'; font-weight: 600; font-size: 19px; margin-bottom: 7px; }
.card p { color: var(--muted); font-size: 15px; }

/* mô tả cách chơi */
.how { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px,1fr)); gap: 14px; }
.step { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; }
.step .n { font-family:'Fredoka'; font-weight:700; color: var(--gold); font-size: 22px; }
.step h4 { font-family:'Fredoka'; font-weight:600; margin: 6px 0 5px; }
.step p { color: var(--muted); font-size: 14px; }

/* ---- Trang nội dung (legal / support) ---- */
.doc { max-width: 780px; margin: 0 auto; padding: 44px 0 20px; }
.doc h1 { font-family: 'Fredoka'; font-weight: 700; font-size: clamp(28px,6vw,42px); }
.doc .updated { color: var(--muted); font-size: 14px; margin: 8px 0 26px; }
.doc h2 { font-family: 'Fredoka'; font-weight: 600; font-size: 22px; margin: 30px 0 10px; color: var(--gold-soft); }
.doc h3 { font-family: 'Fredoka'; font-weight: 600; font-size: 18px; margin: 20px 0 8px; }
.doc p, .doc li { color: #d7ded6; font-size: 16px; }
.doc ul { margin: 10px 0 10px 22px; }
.doc li { margin: 6px 0; }
.doc a { color: var(--gold); }
.doc .panel { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
              padding: 20px 24px; margin: 20px 0; }

/* ---- FAQ ---- */
.faq details {
  background: var(--panel); border: 1px solid var(--line); border-radius: 13px;
  padding: 4px 20px; margin: 10px 0;
}
.faq summary { font-family: 'Fredoka'; font-weight: 500; font-size: 17px; cursor: pointer;
               padding: 14px 0; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: '+'; float: right; color: var(--gold); font-size: 22px; line-height: 1; }
.faq details[open] summary::after { content: '−'; }
.faq details p { color: var(--muted); padding-bottom: 16px; font-size: 15px; }

/* ---- Footer ---- */
footer {
  border-top: 1px solid var(--line); margin-top: 40px; padding: 34px 0;
  color: var(--muted); font-size: 14px;
}
footer .wrap { display: flex; flex-wrap: wrap; gap: 16px 26px; align-items: center; }
footer a { color: var(--muted); text-decoration: none; }
footer a:hover { color: var(--text); }
footer .spacer { margin-left: auto; }

.divider { height: 1px; background: var(--line); border: 0; margin: 30px 0; }