:root{--bg:#F2ECE1;--paper:#FBF8F1;--ink:#2B2622;--ink2:#564C43;--muted:#8A7F73;--line:#DDD2C1;--rule:rgba(43,38,34,.09);--red:#B8352A;--red2:#9A2A21;--navy:#22304F;--navy2:#2E3E63;--env:#E9DDC6;--env2:#DCCBAE;--soft:#EFE6D6;--shadow:0 1px 0 rgba(43,38,34,.05),0 18px 40px -18px rgba(60,40,20,.35);
--wk:'WK','Kaiti SC','STKaiti','KaiTi',serif;--song:'Songti SC','STSong','Noto Serif SC','Source Han Serif SC','Noto Serif CJK SC',serif;color-scheme:light}
@media (prefers-color-scheme:dark){:root{--bg:#14161D;--paper:#1D2029;--ink:#EDE5D6;--ink2:#C8BEAF;--muted:#8F877B;--line:#30343F;--rule:rgba(237,229,214,.07);--red:#D0503E;--red2:#E2654F;--navy:#8FA6D6;--navy2:#A9BDE6;--env:#2A2C35;--env2:#353844;--soft:#252833;--shadow:0 18px 40px -18px rgba(0,0,0,.7);color-scheme:dark}}
*{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%;overflow-x:clip}
body{margin:0;min-height:100vh;background:var(--bg);color:var(--ink);font:16px/1.75 var(--wk);
background-image:radial-gradient(rgba(120,90,50,.06) 1px,transparent 1.2px);background-size:5px 5px}
@media (prefers-color-scheme:dark){body{background-image:radial-gradient(rgba(255,255,255,.025) 1px,transparent 1.2px)}}
button,input,textarea,a{font:inherit;color:inherit;-webkit-tap-highlight-color:transparent}
a{text-decoration:none}
main{max-width:600px;margin:0 auto;padding:14px 18px 10px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
.top{display:flex;justify-content:space-between;align-items:center}
.brand{display:inline-flex;align-items:center;gap:8px;font-size:17px;color:var(--ink);border-radius:8px;padding:2px 4px 2px 0}
.brand img{border-radius:6px}
.now{font-size:13px;color:var(--muted);font-variant-numeric:tabular-nums}
.view{animation:in .45s ease both}
@keyframes in{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}

.hero{padding:26px 2px 6px}
.kicker{margin:0;font-size:14px;color:var(--red);letter-spacing:4px}
.title{margin:8px 0 0;font-weight:400;font-size:44px;line-height:1.2;letter-spacing:1px}
.title em{font-style:normal;color:var(--red);position:relative;white-space:nowrap}
.title em::after{content:'';position:absolute;left:0;right:0;bottom:2px;height:8px;background:var(--red);opacity:.14;border-radius:4px}
.sub{margin:12px 0 0;color:var(--ink2);font-size:16px}

.paper{position:relative;margin:22px 0 12px;background:var(--paper);border-radius:6px;box-shadow:var(--shadow);padding:22px 18px 16px;overflow:hidden;
background-image:linear-gradient(transparent 31px,var(--rule) 31px 32px);background-size:100% 32px;background-position:0 12px}
.air{position:absolute;left:0;right:0;top:0;height:6px;background:repeating-linear-gradient(135deg,var(--red) 0 12px,transparent 12px 18px,var(--navy) 18px 30px,transparent 30px 36px)}
.line{display:flex;align-items:baseline;gap:10px;border-bottom:1px dashed var(--line);padding:4px 0 6px}
.line .lab{flex:none;font-size:14px;color:var(--muted);letter-spacing:2px}
.line input{flex:1;min-width:0;border:0;background:transparent;outline:0;font-size:17px;padding:2px 0}
.sign{margin-top:6px;justify-content:flex-end}.sign input{flex:0 1 210px;text-align:right}
input::placeholder,textarea::placeholder{color:var(--muted);opacity:.75}
.body{display:block;position:relative;margin-top:8px}
textarea{display:block;width:100%;border:0;background:transparent;outline:0;resize:vertical;min-height:224px;font:17px/32px var(--song);padding:0;color:var(--ink)}
.count{position:absolute;right:0;bottom:-22px;font-size:12px;color:var(--muted);font-variant-numeric:tabular-nums}
.count.over{color:var(--red)}
.hp{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}
.paper :focus-visible{outline:2px solid var(--navy);outline-offset:2px;border-radius:4px}

.when{border:0;margin:26px 0 0;padding:16px 0 0;border-top:1px solid var(--line);min-width:0}
.when legend{padding:0;font-size:15px;color:var(--ink2);letter-spacing:2px;float:left;width:100%;margin-bottom:10px}
.chips{clear:both;display:flex;flex-wrap:wrap;gap:8px}
.chip{appearance:none;border:1px solid var(--line);background:var(--paper);color:var(--ink2);border-radius:999px;padding:6px 14px;font-size:15px;line-height:1.4;cursor:pointer;transition:all .15s}
@media (hover:hover){.chip:hover{border-color:var(--navy);color:var(--ink)}}
.chip.on{background:var(--navy);border-color:var(--navy);color:var(--paper)}
.pick{display:flex;gap:10px;margin-top:12px}
.pick label{flex:1;display:flex;flex-direction:column;gap:4px;font-size:13px;color:var(--muted);min-width:0}
.pick input{appearance:none;-webkit-appearance:none;width:100%;min-height:42px;border:1px solid var(--line);border-radius:8px;background:var(--paper);padding:8px 10px;font:16px/1.4 var(--wk);color:var(--ink);outline:0}
.pick input:focus{border-color:var(--navy)}
.pick input::-webkit-calendar-picker-indicator{opacity:.6}
@media (prefers-color-scheme:dark){.pick input::-webkit-calendar-picker-indicator{filter:invert(1)}}
.when-out{margin:12px 0 0;font-size:15px;color:var(--ink2);min-height:1.75em}
.when-out b{color:var(--ink);font-weight:400;border-bottom:2px solid var(--red)}

.btn{appearance:none;display:inline-flex;align-items:center;justify-content:center;gap:6px;border:1.5px solid var(--navy);border-radius:10px;padding:10px 20px;font-size:16px;line-height:1.3;cursor:pointer;text-decoration:none;transition:transform .12s,background .15s,box-shadow .15s;background:transparent;color:var(--navy);white-space:nowrap}
.btn:active{transform:translateY(1px) scale(.99)}
.btn.primary{background:var(--red);border-color:var(--red);color:#FFF7EE;box-shadow:0 6px 16px -8px var(--red)}
.btn.primary:hover{background:var(--red2);border-color:var(--red2)}
.btn.ghost:hover{background:var(--soft)}
.btn.big{width:100%;margin-top:18px;padding:13px 20px;font-size:18px;letter-spacing:6px}
.btn[disabled]{opacity:.55;cursor:progress}
.btn:focus-visible,.tlink:focus-visible,.brand:focus-visible,.chip:focus-visible,.foot a:focus-visible{outline:2px solid var(--navy);outline-offset:3px}
.err{margin:10px 0 0;min-height:1.5em;color:var(--red);font-size:15px}
.err.center{text-align:center}
.tlink{color:var(--ink2);background:linear-gradient(var(--red),var(--red)) 0 100%/100% 1.5px no-repeat;padding-bottom:2px;transition:color .15s}
.tlink:hover{color:var(--red)}

.facts{list-style:none;margin:28px 0 8px;padding:0;display:grid;gap:12px}
.facts li{position:relative;padding-left:22px;color:var(--ink2);font-size:15px}
.facts li::before{content:'';position:absolute;left:2px;top:.62em;width:9px;height:9px;border-radius:50%;background:var(--red);opacity:.8}
.facts b{font-weight:400;color:var(--ink)}

/* 信封 */
.env{position:relative;width:min(100%,340px);aspect-ratio:1.55;margin:34px auto 6px;background:var(--env);border-radius:8px;box-shadow:var(--shadow);perspective:900px}
.env::before{content:'';position:absolute;inset:0;border-radius:8px;background:linear-gradient(to top right,transparent 49.6%,var(--env2) 50%,transparent 50.4%),linear-gradient(to top left,transparent 49.6%,var(--env2) 50%,transparent 50.4%);background-size:50% 100%;background-repeat:no-repeat;background-position:0 0,100% 0;opacity:.8}
.env .flap{position:absolute;left:0;right:0;top:0;height:58%;background:var(--env2);clip-path:polygon(0 0,100% 0,50% 100%);transform-origin:50% 0;border-radius:8px 8px 0 0;z-index:3;transition:transform .7s cubic-bezier(.4,.1,.3,1)}
.env .seal{position:absolute;left:50%;top:58%;width:62px;height:62px;margin:-31px 0 0 -31px;border-radius:50%;z-index:4;display:grid;place-items:center;
background:radial-gradient(circle at 35% 30%,#D9604F,var(--red) 55%,#8E241B);box-shadow:0 3px 8px rgba(80,20,10,.35),inset 0 0 0 4px rgba(255,255,255,.08);transition:transform .35s,opacity .35s}
.env .seal::before{content:'';position:absolute;inset:7px;border-radius:50%;border:1.5px dashed rgba(255,230,220,.55)}
.env .seal span{color:#FBE3DA;font-size:22px;line-height:1}
.pm{position:absolute;right:14px;bottom:12px;width:92px;height:92px;border-radius:50%;border:2px solid var(--navy);color:var(--navy);opacity:.75;transform:rotate(-12deg);display:flex;flex-direction:column;align-items:center;justify-content:center;font-size:11px;line-height:1.35;text-align:center;z-index:2}
.pm b{font-weight:400;font-size:15px;letter-spacing:.5px}
.pm::before{content:'';position:absolute;inset:4px;border-radius:50%;border:1px solid var(--navy);opacity:.6}
.env .letter-peek{position:absolute;left:8%;right:8%;top:10%;bottom:8%;background:var(--paper);border-radius:4px;z-index:1;transition:transform .8s cubic-bezier(.3,.1,.2,1) .35s;box-shadow:0 2px 8px rgba(0,0,0,.08);
background-image:linear-gradient(transparent 15px,var(--rule) 15px 16px);background-size:100% 16px}
.env.ready .seal{animation:pulse 2.2s ease-in-out infinite}
@keyframes pulse{0%,100%{transform:scale(1)}50%{transform:scale(1.06)}}
.env.opening .seal{animation:crack .5s ease forwards}
@keyframes crack{30%{transform:scale(1.15) rotate(-6deg)}100%{transform:scale(.6) rotate(25deg) translateY(30px);opacity:0}}
.env.opening .flap{transform:rotateX(180deg);transition-delay:.25s;z-index:0}
.env.opening .letter-peek{transform:translateY(-62%)}

.h2{margin:16px 0 0;text-align:center;font-weight:400;font-size:32px;letter-spacing:2px}
.lead{margin:8px auto 0;max-width:440px;text-align:center;color:var(--ink2)}
.lead b{font-weight:400;color:var(--ink)}
.note{margin:12px auto 0;max-width:440px;text-align:center;color:var(--muted);font-size:14px}
.again{text-align:center;margin:22px 0 6px}
.btns{display:flex;flex-wrap:wrap;justify-content:center;gap:10px;margin-top:18px}
.linkbox{margin:18px auto 0;max-width:460px;background:var(--paper);border:1px dashed var(--line);border-radius:10px;padding:12px 14px;text-align:center}
.url{font:15px/1.5 ui-monospace,SFMono-Regular,Menlo,monospace;word-break:break-all;user-select:all;color:var(--ink)}

.cd{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;max-width:420px;margin:22px auto 0}
.cd div{background:var(--paper);border-radius:10px;box-shadow:var(--shadow);padding:12px 4px 8px;text-align:center}
.cd b{display:block;font-weight:400;font-size:34px;line-height:1.1;font-variant-numeric:tabular-nums;color:var(--ink)}
.cd span{font-size:13px;color:var(--muted)}
.cd.long div:first-child b{color:var(--red)}

.loading{display:flex;justify-content:center;gap:8px;padding:90px 0}
.loading i{width:10px;height:10px;border-radius:50%;background:var(--red);animation:dot 1s ease-in-out infinite}
.loading i:nth-child(2){animation-delay:.15s}.loading i:nth-child(3){animation-delay:.3s}
@keyframes dot{0%,100%{opacity:.25;transform:translateY(0)}50%{opacity:1;transform:translateY(-6px)}}

.letter{position:relative;margin:30px 0 0;background:var(--paper);border-radius:6px;box-shadow:var(--shadow);padding:30px 22px 22px;overflow:hidden;animation:rise .8s cubic-bezier(.2,.7,.2,1) both;
background-image:linear-gradient(transparent 33px,var(--rule) 33px 34px);background-size:100% 34px;background-position:0 20px}
@keyframes rise{from{opacity:0;transform:translateY(40px) scale(.97)}to{opacity:1;transform:none}}
.lt-to{margin:0;font-size:18px;color:var(--ink2)}
.lt-body{margin:6px 0 0;font:17.5px/34px var(--song);white-space:pre-wrap;word-break:break-word;overflow-wrap:anywhere}
.lt-body p{margin:0;animation:in .6s ease both}
.lt-from{margin:14px 0 0;text-align:right;font-size:18px;color:var(--ink2)}
.lt-meta span{display:block}
.lt-meta{margin:14px 0 0;padding-top:10px;border-top:1px dashed var(--line);font-size:13px;color:var(--muted);text-align:right}

.toast{position:fixed;left:50%;bottom:28px;transform:translate(-50%,20px);background:var(--navy);color:var(--paper);padding:9px 18px;border-radius:999px;font-size:15px;opacity:0;pointer-events:none;transition:all .25s;z-index:9}
.toast.on{opacity:1;transform:translate(-50%,0)}

.foot{max-width:600px;margin:28px auto 0;padding:16px 18px 34px;color:var(--muted);font-size:13px;border-top:1px solid var(--line)}
.foot p{margin:0 0 8px}
.foot .links{display:flex;flex-wrap:wrap;gap:6px 16px}
.foot a{color:var(--ink2);background:linear-gradient(var(--line),var(--line)) 0 100%/100% 1px no-repeat;padding-bottom:1px}
.foot a:hover{color:var(--red);background-image:linear-gradient(var(--red),var(--red))}

@media (min-width:720px){main{padding-top:22px}.title{font-size:54px}.paper{padding:26px 28px 20px}.letter{padding:38px 40px 28px}.cd b{font-size:42px}}
@media (prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important}}
/* 用户写的字用系统宋体，网页字体只裁了界面用字 */
.line input,.lt-to,.lt-from,.lead b.u{font-family:var(--song)}