/* XO4D — 井字格 hero + Papan XO Terpecahkan 卡片流. 棋夜紫灰 #1C1622 × 棋格藤紫 #D5B4FF */
:root{
  --bg:#1C1622;--panel:#261D30;--panel2:#2E2440;--text:#F2EBFA;--muted:#BCAED6;
  --accent:#D5B4FF;--accent-soft:#8F7BB5;--ink:#120C1A;
  --glow:0 0 12px rgba(213,180,255,.4),0 0 26px rgba(213,180,255,.2);
  --grad-panel:linear-gradient(150deg,#2E2440 0%,#1C1622 100%);
  --font-h:'Unica One',sans-serif;--font-b:'Neuton',serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--text);font-family:var(--font-b);line-height:1.7;font-size:17px}
img,svg{max-width:100%;vertical-align:middle}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.container{width:100%;max-width:1160px;margin:0 auto;padding:0 16px}
.container.narrow{max-width:840px}
.center{text-align:center}
.site-header{position:sticky;top:0;z-index:50;background:rgba(28,22,34,.92);backdrop-filter:blur(10px);border-bottom:1px solid rgba(213,180,255,.32)}
.header-in{display:flex;align-items:center;gap:14px;min-height:60px}
.brand{display:inline-flex;align-items:center;gap:8px;font-family:var(--font-h);font-weight:400;font-size:1.15rem;color:var(--text);white-space:nowrap;letter-spacing:.08em}
.brand:hover{text-decoration:none}
.nav-desktop{display:none;margin-left:auto;gap:18px}
.nav-desktop a{color:var(--muted);font-weight:700;font-size:.95rem}
.nav-desktop a:hover{color:var(--accent);text-decoration:none}
.header-cta{display:flex;gap:8px;margin-left:auto}
.nav-desktop+.header-cta{margin-left:0}
.btn{display:inline-block;padding:10px 20px;border-radius:10px;font-family:var(--font-b);font-weight:700;font-size:.95rem;cursor:pointer;border:1px solid transparent;transition:transform .15s}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-primary{background:linear-gradient(135deg,#D5B4FF,#A886D9);color:#1C1622;box-shadow:var(--glow)}
.btn-secondary{background:transparent;color:var(--accent);border-color:rgba(213,180,255,.55)}
.btn-block{display:block;width:100%;text-align:center}
.pulse{animation:pulse-glow 2s infinite}
@keyframes pulse-glow{0%,100%{box-shadow:0 0 8px rgba(213,180,255,.4)}50%{box-shadow:0 0 22px rgba(213,180,255,.8)}}
.nav-toggle{display:none}
.burger{display:flex;flex-direction:column;gap:4px;cursor:pointer;padding:6px;margin-left:4px}
.burger span{width:22px;height:2px;background:var(--accent);border-radius:2px}
.m-nav{display:none;background:var(--panel);border-bottom:1px solid rgba(213,180,255,.3)}
.m-nav-group{padding:10px 16px}
.m-nav-group h3{font-size:.8rem;text-transform:uppercase;letter-spacing:.08em;color:var(--accent);margin-bottom:6px;font-weight:700;font-family:var(--font-b)}
.m-nav-group a{display:block;padding:6px 0;color:var(--text)}
.nav-toggle:checked~.m-nav{display:block}
/* 井字格 hero（纯 CSS） */
.xo-hero{padding:44px 0 6px;background:radial-gradient(60% 70% at 50% 0%,rgba(213,180,255,.13) 0%,rgba(28,22,34,0) 70%)}
.xo-head{text-align:center}
.xo-head h1{font-family:var(--font-h);font-weight:400;font-size:clamp(2.4rem,7vw,4rem);letter-spacing:.07em;text-shadow:0 2px 0 #8F7BB5,0 0 26px rgba(213,180,255,.5)}
.hero-sub{max-width:640px;margin:12px auto 20px;color:var(--muted)}
.hero-cta{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.xo-board{width:min(300px,78vw);aspect-ratio:1;margin:30px auto 0;display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:repeat(3,1fr);gap:6px;padding:10px;background:rgba(38,29,48,.72);border:3px solid rgba(213,180,255,.6);border-radius:18px;box-shadow:0 0 26px rgba(213,180,255,.28),inset 0 0 30px rgba(213,180,255,.08)}
.xo-cell{border:1px dashed rgba(213,180,255,.16);border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:16px}
.xo-cell.next{border:1px solid rgba(213,180,255,.55);animation:cell-breath 1.6s ease-in-out infinite}
@keyframes cell-breath{0%,100%{background:rgba(213,180,255,.05)}50%{background:rgba(213,180,255,.18)}}
.mark-x{position:relative;display:block;width:54%;height:54%;animation:mark-drop .5s cubic-bezier(.2,.9,.3,1.4) backwards}
.mark-x::before,.mark-x::after{content:"";position:absolute;left:50%;top:50%;width:100%;height:10%;background:var(--accent);border-radius:99px;box-shadow:0 0 10px rgba(213,180,255,.6);transform:translate(-50%,-50%) rotate(45deg)}
.mark-x::after{transform:translate(-50%,-50%) rotate(-45deg)}
.mark-o{display:block;width:52%;height:52%;border:.42em solid var(--text);border-radius:50%;box-shadow:0 0 10px rgba(242,235,250,.35);animation:mark-drop .5s cubic-bezier(.2,.9,.3,1.4) backwards}
@keyframes mark-drop{from{opacity:0;transform:translateY(-24px) scale(.5)}to{opacity:1;transform:translateY(0) scale(1)}}
.d1{animation-delay:.15s}.d2{animation-delay:.55s}.d3{animation-delay:.95s}.d4{animation-delay:1.35s}.d5{animation-delay:1.75s}
.stage-chips{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin:16px 0 4px}
.chip{font-size:.78rem;letter-spacing:.06em;color:var(--accent);border:1px solid rgba(213,180,255,.4);border-radius:99px;padding:3px 14px;background:rgba(28,22,34,.6)}
.chip-soft{color:#EDE4F8;border-color:#8F7BB5}
.section{padding:38px 0}
.section-alt{background:rgba(38,29,48,.55)}
.sec-title{font-family:var(--font-h);font-weight:400;font-size:1.5rem;letter-spacing:.05em;margin-bottom:18px;text-align:center}
.sec-sub{color:var(--muted);text-align:center;max-width:640px;margin:-8px auto 18px;font-size:.92rem}
.grid-2,.grid-3,.grid-4{display:grid;gap:16px;grid-template-columns:1fr;margin-bottom:8px}
.glow-card{display:block;background:var(--grad-panel);border:1px solid rgba(213,180,255,.35);border-radius:14px;padding:18px;color:var(--text);transition:border-color .15s,box-shadow .15s}
.glow-card:hover{border-color:var(--accent);box-shadow:var(--glow);text-decoration:none}
.glow-card h3{font-size:1.05rem;margin-bottom:6px;color:var(--accent)}
.glow-card p{color:var(--muted);font-size:.92rem}
.nc-icon{font-size:1.4rem;display:block;margin-bottom:8px;color:var(--accent);letter-spacing:.1em}
/* Papan XO Terpecahkan 特色板块 */
.solved-grid{display:grid;gap:16px;grid-template-columns:1fr;margin:8px 0 16px}
.solved-card{background:var(--grad-panel);border:1px solid rgba(213,180,255,.35);border-radius:14px;padding:18px}
.mini-board{width:180px;aspect-ratio:1;margin:0 auto;display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:repeat(3,1fr);gap:4px;padding:7px;background:rgba(28,22,34,.7);border:2px solid rgba(213,180,255,.5);border-radius:14px;box-shadow:0 0 16px rgba(213,180,255,.2);font-size:11px}
.mini-board .xo-cell{border-radius:7px;border:1px dashed rgba(213,180,255,.14)}
.solved-cap{font-size:.9rem;color:var(--muted);margin-top:12px;text-align:center}
.solved-cap strong{color:var(--accent)}
.solved-note{text-align:center;color:var(--muted);font-size:.88rem;max-width:640px;margin:0 auto}
.pill-il{display:inline-block;font-size:.68rem;letter-spacing:.14em;font-weight:700;color:var(--accent);border:1px solid rgba(213,180,255,.5);border-radius:99px;padding:1px 10px;margin-right:8px;vertical-align:middle}
.trust-zone p{max-width:640px;margin:10px auto;color:var(--muted)}
.trust-zone .pill-18{margin:6px 0 12px}
.flow{margin:16px 0;padding:20px;display:block}
.flow>*{border-radius:10px;padding:11px 14px;margin-bottom:9px;font-size:.95rem;background:rgba(28,22,34,.55);border:1px solid rgba(213,180,255,.35)}
.flow-step strong{color:var(--accent)}
.flow-end{border:1px dashed rgba(213,180,255,.5);color:var(--muted)}
.prose .note{color:var(--muted);font-size:.9rem}
.page-head{padding-top:22px}
.page-head h1,.prose h1{font-family:var(--font-h);font-weight:400;font-size:clamp(1.6rem,4.5vw,2.3rem);line-height:1.3;letter-spacing:.04em}
.prose h2{font-family:var(--font-h);font-weight:400;font-size:1.4rem;margin:26px 0 10px;line-height:1.35;letter-spacing:.03em}
.prose h3{font-size:1.1rem;font-weight:700;margin:20px 0 8px;color:var(--accent)}
.prose p{margin:0 0 14px}
.prose ul,.prose ol{margin:0 0 14px 22px}
.prose li{margin-bottom:6px}
.steps li{margin-bottom:10px}
.steps li strong{color:var(--accent)}
.edu-fig{margin:18px 0}
.edu-fig img{width:100%;height:auto;border-radius:12px;border:1px solid rgba(213,180,255,.35);box-shadow:0 0 18px rgba(213,180,255,.15)}
.edu-fig figcaption{font-size:.85rem;color:var(--muted);margin-top:8px;text-align:center}
.quick-form{display:grid;gap:8px;max-width:360px;margin:12px 0}
.quick-form label{font-size:.85rem;color:var(--muted)}
.quick-form input{background:#1C1622;border:1px solid rgba(213,180,255,.4);border-radius:8px;padding:10px 12px;color:var(--text);font-family:var(--font-b)}
.quick-form input:focus{outline:none;border-color:var(--accent)}
.kamus-grid{display:grid;gap:10px;margin:14px 0}
.kamus-item{background:var(--grad-panel);border:1px solid rgba(213,180,255,.3);border-radius:10px;overflow:hidden}
.kamus-item summary{cursor:pointer;padding:13px 16px;font-weight:700;list-style:none;position:relative}
.kamus-item summary::-webkit-details-marker{display:none}
.kamus-item summary::after{content:"+";position:absolute;right:16px;color:var(--accent)}
.kamus-item[open] summary::after{content:"−"}
.kamus-item p{padding:0 16px 14px;color:var(--muted);font-size:.95rem}
.err-wrap{padding:70px 16px}
.err-code{font-family:var(--font-h);font-size:5rem;color:var(--accent);text-shadow:var(--glow);letter-spacing:.1em}
.err-wrap .btn{margin:18px 0}
.crumbs{padding:12px 0 0;font-size:.82rem;color:var(--muted)}
.crumbs ol{list-style:none;display:flex;flex-wrap:wrap;gap:6px}
.crumbs li+li::before{content:"›";margin-right:6px;color:var(--accent)}
.site-footer{background:var(--panel);border-top:1px solid rgba(213,180,255,.35);padding:36px 0 92px;margin-top:30px}
.foot-grid{display:grid;gap:24px;grid-template-columns:1fr}
.foot-brand p{color:var(--muted);font-size:.9rem;margin:10px 0}
.foot-col h3{font-size:.85rem;text-transform:uppercase;letter-spacing:.08em;color:var(--accent);margin-bottom:8px;font-weight:700;font-family:var(--font-b)}
.foot-col a{display:block;color:var(--muted);padding:3px 0;font-size:.92rem}
.foot-col a:hover{color:var(--accent);text-decoration:none}
.pill-18{display:inline-block;border:1px solid var(--accent);color:var(--accent);border-radius:999px;padding:2px 12px;font-weight:700;font-size:.85rem}
.foot-bottom{margin-top:24px;padding-top:16px;border-top:1px solid rgba(213,180,255,.25);color:var(--muted);font-size:.85rem}
.float-cta{position:fixed;left:0;right:0;bottom:0;z-index:60;padding:10px 16px calc(10px + env(safe-area-inset-bottom));background:rgba(28,22,34,.92);backdrop-filter:blur(8px);border-top:1px solid rgba(213,180,255,.4)}
@media (max-width:767px){
  .header-in{gap:8px}
  .brand{font-size:.98rem}
  .brand .logo-mark{width:26px;height:26px}
  .header-cta{gap:6px}
  .header-cta .btn{padding:8px 13px;font-size:.85rem}
  .burger{padding:5px}
}
@media (min-width:768px){
  .grid-2{grid-template-columns:repeat(2,1fr)}
  .grid-3{grid-template-columns:repeat(3,1fr)}
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .solved-grid{grid-template-columns:repeat(3,1fr)}
  .foot-grid{grid-template-columns:2fr 1fr 1.4fr 1fr}
  .nav-desktop{display:flex}
  .header-cta{margin-left:0}
  .burger{display:none}
  .m-nav{display:none!important}
  .float-cta{left:auto;right:18px;bottom:18px;border-radius:12px;border:1px solid rgba(213,180,255,.5)}
  .float-cta .btn-block{width:auto}
}
@media (min-width:1024px){.grid-4{grid-template-columns:repeat(4,1fr)}}
@media (prefers-reduced-motion:reduce){
  .pulse,.mark-x,.mark-o,.xo-cell.next,.jackpot-blink,.masuk-btn,.masuk-btn::after,.jp-spark{animation:none}
}

/* ===== Float CTA Jackpot v2 (2026-09-13): 底部居中 + 闪烁 ===== */
.float-cta{left:50%;right:auto;transform:translateX(-50%);width:100%;max-width:600px;margin:0;display:block}
.float-inner{display:flex;align-items:center;justify-content:center;gap:12px;flex-wrap:wrap}
.jackpot-tag{display:inline-flex;align-items:center;gap:6px;font-weight:800;font-size:1rem;letter-spacing:.02em;color:#FFE066;text-shadow:0 0 10px rgba(255,224,102,.6)}
.jackpot-blink{animation:jackpot-blink 1.1s ease-in-out infinite}
@keyframes jackpot-blink{0%,100%{opacity:1;text-shadow:0 0 10px rgba(255,224,102,.85),0 0 22px rgba(255,224,102,.45)}50%{opacity:.5;text-shadow:0 0 4px rgba(255,224,102,.3)}}
.masuk-btn{position:relative;overflow:hidden;white-space:nowrap;flex:0 0 auto;font-weight:800;letter-spacing:.02em;animation:masuk-glow 1.4s ease-in-out infinite}
.masuk-btn::after{content:"";position:absolute;top:0;left:-80%;width:55%;height:100%;background:linear-gradient(105deg,rgba(255,255,255,0) 0%,rgba(255,255,255,.55) 50%,rgba(255,255,255,0) 100%);transform:skewX(-20deg);animation:masuk-shine 1.8s linear infinite}
@keyframes masuk-shine{0%{left:-80%}55%,100%{left:130%}}
@keyframes masuk-glow{0%,100%{box-shadow:0 0 8px rgba(255,215,80,.55)}50%{box-shadow:0 0 24px rgba(255,215,80,.95),0 0 40px rgba(255,180,40,.5)}}
.jp-spark{display:inline-block;animation:spark-twinkle 1s ease-in-out infinite}
@keyframes spark-twinkle{0%,100%{transform:scale(1);opacity:1}50%{transform:scale(.55) rotate(18deg);opacity:.45}}
@media (prefers-reduced-motion:reduce){.jackpot-blink,.masuk-btn,.masuk-btn::after,.jp-spark{animation:none}}