html,body{height:100%;background:#cfd8ea}
body{font-size:20px;line-height:1.45;overscroll-behavior:none}
#app{position:relative;max-width:480px;height:100vh;height:100dvh;margin:0 auto;background:var(--paper);overflow:hidden;display:flex;flex-direction:column;box-shadow:0 0 30px rgba(0,0,0,.2)}
.topbar{flex:none;height:60px;display:flex;align-items:center;gap:10px;padding:0 14px;background:var(--navy);color:#fff;border-bottom:3px solid var(--gold)}
.topbar .badge{width:34px}
.topbar .t{flex:1;font-weight:800;font-size:20px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.pill{background:var(--gold);color:var(--deep);font-weight:900;border-radius:20px;padding:4px 12px;font-size:18px;white-space:nowrap}
.viewport{flex:1;overflow:hidden;position:relative;touch-action:pan-y}
.track{display:flex;height:100%;transition:transform .35s ease;will-change:transform}
.screen{flex:0 0 100%;width:100%;height:100%;overflow-y:auto;overflow-x:hidden;padding:20px 20px 28px;-webkit-overflow-scrolling:touch}
.order{font-family:var(--mono);font-size:18px;font-weight:700;letter-spacing:.12em;color:var(--blue);margin-bottom:6px}
.q{font-size:30px;font-weight:900;line-height:1.2;color:var(--navy)}
.q .zh{display:block;font-size:20px;margin-top:6px}
.hero{position:relative;margin:-20px -20px 18px;height:210px;background:url(../img/sunset-field.webp) center/cover}
.hero::after{content:"";position:absolute;inset:0;background:linear-gradient(180deg,rgba(6,22,52,.1),rgba(6,22,52,.85))}
.hero .ai-cap{position:absolute;right:10px;top:10px;z-index:2}
.hero .in{position:absolute;left:20px;right:20px;bottom:16px;z-index:2;color:#fff;display:flex;gap:14px;align-items:flex-end}
.hero .badge{width:74px;flex:none}
.hero h1{font-size:30px;line-height:1.1}
.hero h1 small{display:block;font-size:20px;color:var(--gold2);font-weight:700}
.btn{font-family:var(--font);display:flex;align-items:center;justify-content:center;gap:8px;width:100%;min-height:60px;border:0;border-radius:16px;background:var(--navy);color:#fff;font-size:22px;font-weight:900;cursor:pointer;margin-top:14px;box-shadow:0 4px 0 var(--deep)}
.btn:active{transform:translateY(2px);box-shadow:0 2px 0 var(--deep)}
.btn.gold{background:var(--gold);color:var(--deep);box-shadow:0 4px 0 #9c7618}
.btn[disabled]{opacity:.5}
.grid5{display:grid;grid-template-columns:repeat(5,1fr);gap:10px;margin-top:12px}
.grid5 button{font-family:var(--font);min-height:56px;border-radius:14px;border:3px solid var(--navy);background:#fff;font-size:24px;font-weight:900;color:var(--navy)}
.grid5 button.on{background:var(--navy);color:var(--gold2)}
.field{width:100%;min-height:60px;font-size:24px;font-family:var(--font);border:3px solid var(--navy);border-radius:16px;padding:10px 16px;margin-top:16px}
.chips{display:flex;flex-wrap:wrap;gap:10px;margin-top:12px}
.chips button{font-family:var(--font);min-height:48px;padding:0 18px;border-radius:24px;border:2px solid var(--blue);background:#fff;color:var(--navy);font-size:20px;font-weight:700}
.opt{font-family:var(--font);display:flex;align-items:center;gap:14px;width:100%;min-height:76px;text-align:left;padding:12px 16px;margin-top:12px;border-radius:18px;border:3px solid #c8d3e8;background:#fff;font-size:20px;color:var(--ink);cursor:pointer}
.opt .n{flex:none;width:48px;height:48px;border-radius:12px;background:var(--navy);color:var(--gold2);font-size:26px;font-weight:900;display:flex;align-items:center;justify-content:center}
.opt.picked{border-color:var(--blue);background:#e8f0ff}
.opt.right{border-color:var(--ok);background:#e6f7ee}
.opt.wrong{border-color:var(--bad);background:#fdecea}
.status{margin-top:14px;min-height:30px;font-weight:800;color:var(--blue)}
details.tip{margin-top:10px;background:#fff;border:2px solid #c8d3e8;border-radius:16px;overflow:hidden}
details.tip summary{list-style:none;min-height:56px;display:flex;align-items:center;gap:10px;padding:0 16px;font-weight:800;color:var(--navy);cursor:pointer}
details.tip summary::-webkit-details-marker{display:none}
details.tip summary::after{content:"＋";margin-left:auto;font-size:24px;color:var(--gold)}
details.tip[open] summary::after{content:"－"}
details.tip .body{padding:0 16px 14px;font-size:20px}
details.tip .wb{display:flex;flex-wrap:wrap;gap:8px}
details.tip .wb span{background:var(--paper);border-radius:12px;padding:4px 10px}
.minicloud{margin-top:14px;background:#fff;border-radius:16px;border:2px solid var(--gold);padding:12px;min-height:120px}
/* flip card */
.flip{perspective:1200px;margin-top:6px;cursor:pointer}
.flip .inner{position:relative;height:330px;transition:transform .5s;transform-style:preserve-3d}
.flip.on .inner{transform:rotateY(180deg)}
.flip .face{position:absolute;inset:0;backface-visibility:hidden;-webkit-backface-visibility:hidden;border-radius:24px;background:linear-gradient(160deg,var(--navy),var(--deep));color:#fff;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;padding:18px;border:4px solid var(--gold)}
.flip .back{transform:rotateY(180deg);background:#fff;color:var(--ink)}
.flip svg{width:150px;height:150px}
.flip .w{font-size:52px;font-weight:900;line-height:1.05}
.flip .ipa{font-size:20px;color:#c9d6f0;font-family:"Noto Sans","Segoe UI",sans-serif}
.flip .cn{font-size:46px;font-weight:900;color:var(--navy)}
.flip .ex{font-size:22px;margin-top:10px}
.flip .hint{font-size:20px;color:var(--gold2);margin-top:8px}
.flip .back .hint{color:var(--muted)}
.say{font-family:var(--font);min-height:48px;min-width:48px;border-radius:24px;border:2px solid var(--gold2);background:transparent;color:#fff;font-size:20px;font-weight:800;padding:0 16px;margin-top:8px}
.tags{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}
.tags span{font-size:20px;font-weight:700;background:#e8f0ff;color:var(--navy);border-radius:14px;padding:2px 10px}
.two{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.two .opt{justify-content:center;font-size:22px;font-weight:800;min-height:64px}
.statrow{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-top:14px}
.statrow div{background:var(--navy);color:#fff;border-radius:16px;padding:10px;text-align:center;font-size:20px;font-weight:700;border-bottom:4px solid var(--gold)}
.statrow b{display:block;font-size:40px;color:var(--gold2);line-height:1.1}
.acc summary b{margin-left:auto;margin-right:6px;font-size:22px;color:var(--blue)}
.acc.hot{border-color:var(--gold);background:#fffaf0}
.acc.hot summary b{color:#b07d00}
.lbm .r{display:grid;grid-template-columns:44px 1fr 48px;align-items:center;gap:8px;min-height:48px;font-weight:800}
.lbm .bar{height:16px;background:#dfe6f3;border-radius:8px;overflow:hidden}
.lbm .bar i{display:block;height:100%;background:var(--gold)}
.lbm .r.mine{color:var(--blue)}
.mybadges{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:10px;text-align:center;font-size:18px;font-weight:700}
.navbar{flex:none;height:84px;display:flex;align-items:center;gap:12px;padding:0 14px;background:#fff;border-top:2px solid #dbe3f1}
.navbar button{font-family:var(--font);min-width:96px;min-height:56px;border-radius:16px;border:3px solid var(--navy);background:#fff;font-size:20px;font-weight:900;color:var(--navy)}
.navbar button.next{background:var(--navy);color:#fff}
.navbar .dots{flex:1;display:flex;justify-content:center;gap:8px}
.navbar .dots i{width:10px;height:10px;border-radius:50%;background:#c8d3e8;display:block}
.navbar .dots i.on{background:var(--gold);width:24px;border-radius:6px}
.pace{position:absolute;left:12px;right:12px;top:-120px;z-index:10;background:var(--deep);color:#fff;border:3px solid var(--gold);border-radius:16px;padding:10px 12px;display:flex;align-items:center;gap:10px;transition:top .35s;font-size:18px}
.pace.on{top:70px}
.pace button{font-family:var(--font);min-height:48px;border-radius:12px;border:0;background:var(--gold);color:var(--deep);font-weight:900;font-size:18px;padding:0 14px;white-space:nowrap}
.toast{position:absolute;left:50%;bottom:110px;transform:translateX(-50%) translateY(40px);opacity:0;background:var(--ok);color:#fff;font-weight:900;font-size:22px;border-radius:30px;padding:10px 24px;transition:.3s;z-index:11;white-space:nowrap}
.toast.on{opacity:1;transform:translateX(-50%) translateY(0)}
.demo-line{margin-top:12px;font-size:18px}

.hero .ai-cap{font-size:16px}
#afterWord{display:none}
.sent #beforeWord{display:none}
.sent #afterWord{display:block}
.linkbtn{font-family:var(--font);min-height:48px;border:0;background:none;color:var(--blue);font-size:20px;font-weight:800;text-decoration:underline;padding:0}