/* ============ Con kể tiếp nhé: giao diện ============ */
:root{
  --paper:#EDF0F3; --ink:#1E2533; --soft:#5D6878; --blue:#2E4A72; --dawn:#C4864A; --rule:#CBD2DB;
  --sheet:#FAF9F5; --sheet-line:rgba(46,74,114,.10); --margin-line:rgba(196,134,74,.35);
  --bubble:#E0E6ED; --bubble-me:#2E4A72; --bubble-me-ink:#F3F5F8;
  --sky:linear-gradient(172deg,#121B2F 0%,#1F3354 34%,#4A5F84 60%,#A79A97 82%,#E8BA88 100%);
  --lora:"Lora", Georgia, "Times New Roman", serif;
  --body:var(--lora); --size:19px; --grain:.035;
}
html[data-theme="giay"]{ --paper:#EEE5D2; --ink:#34291C; --soft:#786A56; --blue:#3E5679; --dawn:#AD7236; --rule:#D8CAB0; --sheet:#F8F2E5; --sheet-line:rgba(120,90,50,.13); --margin-line:rgba(173,114,54,.35); --bubble:#E4D9C2; --bubble-me:#3E5679; }
html[data-theme="dem"]{ --paper:#11151C; --ink:#D7DDE5; --soft:#8A94A2; --blue:#8DA8D0; --dawn:#DDA76B; --rule:#27303C; --sheet:#171D26; --sheet-line:rgba(141,168,208,.08); --margin-line:rgba(221,167,107,.25); --bubble:#1E2631; --bubble-me:#34507A; --bubble-me-ink:#EEF2F7; --grain:.03; }
html[data-font="literata"]{ --body:"Literata", Georgia, serif; }
html[data-font="sans"]{ --body:system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif; }

*{box-sizing:border-box}
html{background:var(--paper)}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--lora);font-size:16px;line-height:1.55;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
body::before{content:"";position:fixed;inset:0;pointer-events:none;z-index:50;opacity:var(--grain);mix-blend-mode:multiply;
  background-image:url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0  0 0 0 0 0  0 0 0 0 0  0 0 0 1 0'/></filter><rect width='160' height='160' filter='url(%23n)'/></svg>")}
html[data-theme="dem"] body::before{mix-blend-mode:screen}
a{color:inherit}
:focus-visible{outline:2px solid var(--blue);outline-offset:3px;border-radius:2px}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
h1,h2{font-weight:400}

/* ---------- thanh trên ---------- */
.progress{position:fixed;top:0;left:0;height:2px;width:0;background:var(--dawn);z-index:20}
.bar{position:sticky;top:0;z-index:10;display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 24px;
  background:color-mix(in srgb,var(--paper) 88%,transparent);backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);border-bottom:1px solid var(--rule)}
.pg-home .bar{border-bottom-color:transparent}
.mark{font-size:13.5px;letter-spacing:.2em;text-decoration:none;white-space:nowrap}
.mark i{font-style:normal;color:var(--dawn);margin:0 .45em}
.nav{display:flex;align-items:center;gap:20px;font-size:15px}
.nav a{text-decoration:none;color:var(--soft)}
.nav a[aria-current]{color:var(--ink);text-decoration:underline;text-decoration-color:var(--dawn);text-underline-offset:6px}
.aa{font-size:16px;padding:4px 9px;border:1px solid var(--rule);border-radius:6px;line-height:1.1}

/* ---------- bảng tùy chỉnh ---------- */
.sheet{position:fixed;right:16px;top:60px;z-index:30;width:min(340px,calc(100vw - 32px));background:var(--paper);border:1px solid var(--rule);border-radius:12px;padding:16px 18px;box-shadow:0 18px 50px -12px rgba(15,22,35,.35);display:none;font-size:14px}
.sheet.on{display:block}
.row{margin-bottom:16px}.row:last-child{margin-bottom:0}
.lb{color:var(--soft);margin-bottom:8px}
.seg{display:flex;gap:6px}
.seg button{flex:1;padding:8px 4px;border:1px solid var(--rule);border-radius:8px;white-space:nowrap}
.seg button[aria-pressed="true"]{border-color:var(--ink);background:color-mix(in srgb,var(--ink) 6%,transparent)}
.sw{display:inline-block;width:10px;height:10px;border-radius:50%;margin-right:6px;border:1px solid rgba(0,0,0,.2)}
.sw-sang{background:#EDF0F3}.sw-giay{background:#EEE5D2}.sw-dem{background:#11151C}
.f-literata{font-family:"Literata",Georgia,serif}.f-sans{font-family:system-ui,sans-serif}

/* ---------- giấy thư (dùng chung) ---------- */
.paper{--lh:1.95em;--pad:1.3em;position:relative;display:block;background-color:var(--sheet);color:var(--ink);text-decoration:none;
  padding:var(--pad) 1.5em var(--pad) 2.6em;line-height:var(--lh);font-style:italic;
  background-image:
    linear-gradient(to right,transparent 1.7em,var(--margin-line) 1.7em,var(--margin-line) calc(1.7em + 1px),transparent calc(1.7em + 1px)),
    repeating-linear-gradient(to bottom,transparent 0,transparent calc(var(--lh) - 1px),var(--sheet-line) calc(var(--lh) - 1px),var(--sheet-line) var(--lh));
  background-position:0 0,0 var(--pad);background-repeat:no-repeat,repeat;
  box-shadow:0 1px 0 var(--rule),0 22px 40px -28px rgba(15,25,45,.45);border-radius:2px}
.paper p{margin:0}

/* ---------- trang chủ ---------- */
.hero{max-width:1060px;margin:0 auto;padding:64px 32px 40px;display:grid;grid-template-columns:minmax(220px,300px) 1fr;gap:72px;align-items:center}
.cover{position:relative;aspect-ratio:2/3;width:100%;border-radius:3px 8px 8px 3px;background:var(--sky);container-type:inline-size;overflow:hidden;color:#FFF8EE;
  box-shadow:0 40px 70px -40px rgba(12,20,38,.75),0 3px 8px rgba(12,20,38,.18)}
.cover::before{content:"";position:absolute;left:0;top:0;bottom:0;width:4.5%;background:linear-gradient(to right,rgba(0,0,0,.28),rgba(255,255,255,.06) 70%,transparent)}
.cover::after{content:"";position:absolute;inset:auto -20% -30% -20%;height:55%;background:radial-gradient(ellipse at 70% 100%,rgba(255,214,160,.55),transparent 65%);opacity:0;animation:glow 2.6s .6s ease forwards}
.cv-series{position:absolute;top:8%;left:11%;font-size:4cqw;letter-spacing:.24em;color:rgba(255,248,238,.72)}
.cv-series i{font-style:normal;color:#F3C996;margin:0 .45em}
.cv-slash{position:absolute;inset:0;width:100%;height:100%}
.cv-slash line{stroke-dasharray:400;stroke-dashoffset:400;animation:draw 2s .2s cubic-bezier(.6,.1,.2,1) forwards}
.cv-title{position:absolute;left:11%;right:9%;bottom:16%;font-style:italic;font-size:12.5cqw;line-height:1.08;z-index:1}
.cv-author{position:absolute;left:11%;bottom:8%;font-size:4cqw;letter-spacing:.22em;color:rgba(255,248,238,.78);z-index:1}
@keyframes draw{to{stroke-dashoffset:0}}
@keyframes glow{to{opacity:1}}
.hero-text h1{font-style:italic;font-size:clamp(40px,5.4vw,64px);line-height:1.05;margin:0}
.by{color:var(--soft);margin:12px 0 0;font-size:16px}
.blurb{font-size:19px;line-height:1.75;margin:28px 0 32px;max-width:34rem}
.cta{display:flex;flex-wrap:wrap;gap:12px}
.btn{display:inline-block;text-decoration:none;font-size:16px;padding:11px 20px;border-radius:999px;border:1px solid var(--ink)}
.btn.solid{background:var(--ink);color:var(--paper)}
.btn:hover{border-color:var(--dawn)}
.home-letter{max-width:36rem;margin:40px auto 72px;padding:0 24px}
.home-letter .paper{font-size:19px;transform:rotate(-.7deg);transition:transform .4s ease}
.home-letter .paper:hover{transform:rotate(0)}
.home-letter .more{display:block;font-style:normal;font-size:15px;color:var(--blue);margin-top:.2em;text-decoration:underline;text-underline-offset:4px}
.home-list,.toc{max-width:40rem;margin:0 auto;padding:0 24px}
.home-list h2{font-size:24px;margin:0 0 8px}
.all{margin:16px 0 0;font-size:15px}.all a{color:var(--blue)}

/* ---------- danh sách chương ---------- */
.list{list-style:none;margin:0;padding:0}
.list li a{display:grid;grid-template-columns:3rem 1fr auto;gap:12px;align-items:baseline;padding:14px 0;text-decoration:none;border-bottom:1px solid var(--rule)}
.list li:first-child a{border-top:1px solid var(--rule)}
.list .num{font-size:24px;color:var(--dawn);font-variant-numeric:lining-nums tabular-nums;line-height:1}
.list .t{font-size:19px}
.list .d{font-size:13px;color:var(--soft)}
.list li a:hover .t{text-decoration:underline;text-decoration-color:var(--dawn);text-underline-offset:5px}
.list li.read .t{color:var(--soft)}
.list li.read .t::after{content:"  đã đọc";font-size:12px;font-style:italic;color:var(--soft)}

/* ---------- mục lục ---------- */
.toc{padding-top:56px}
.toc h1{font-size:44px;margin:0 0 40px}
.part{margin-bottom:48px}
.part h2{margin:0 0 14px;display:flex;flex-direction:column}
.pno{font-size:15px;color:var(--soft)}
.pname{font-style:italic;font-size:32px;line-height:1.2}
.later{color:var(--soft);font-style:italic}

/* ---------- trang đọc ---------- */
.reader{max-width:calc(34rem + 48px);margin:0 auto;padding:56px 24px 24px}
.ch-top{position:relative;padding-top:8px;isolation:isolate}
.ch-big{position:absolute;right:-8px;top:-44px;font-size:150px;line-height:1;color:color-mix(in srgb,var(--rule) 55%,var(--paper));z-index:-1;font-variant-numeric:lining-nums;user-select:none}
.ch-part{margin:0;font-size:15px;color:var(--soft)}
.ch-head{margin:6px 0 0}
.ch-head .no{display:block;font-size:16px;color:var(--dawn)}
.ch-head .nm{display:block;font-size:clamp(32px,6vw,44px);line-height:1.15;margin-top:2px}
.fragment{margin:44px 0 60px;font-size:calc(var(--size) * .95);color:color-mix(in srgb,var(--ink) 82%,var(--paper))}
.body{font-family:var(--body);font-size:var(--size);line-height:1.8}
.body p{margin:0 0 .9em}
.body em{font-style:italic}
.brk{text-align:center;font-family:var(--lora);font-size:1.7em;line-height:1;color:var(--dawn);margin:1.5em 0}
.chat{margin:1.4em 0;display:flex;flex-direction:column;gap:6px;font-size:.84em;line-height:1.45}
.msg{max-width:80%;padding:8px 13px;border-radius:15px;background:var(--bubble);align-self:flex-start;border-bottom-left-radius:4px}
.msg .who{display:block;font-size:.8em;color:var(--soft)}
.msg.me{align-self:flex-end;background:var(--bubble-me);color:var(--bubble-me-ink);border-bottom-left-radius:15px;border-bottom-right-radius:4px}
.endmark{margin:64px 0 0;text-align:center;font-size:15px;color:var(--soft);font-style:italic}
.endmark a{color:var(--blue)}
.pager{display:grid;grid-template-columns:1fr auto 1fr;gap:10px;align-items:end;margin-top:40px;padding-top:20px;border-top:1px solid var(--rule);font-size:14px}
.pager a{text-decoration:none;color:var(--soft)}
.pager small{display:block;font-size:13px;color:var(--soft)}
.pager b{font-weight:400;font-size:17px;color:var(--ink);display:block;margin-top:2px}
.pager .nx{text-align:right}
.pager .off small{opacity:.6}
.pager a:hover b{text-decoration:underline;text-decoration-color:var(--dawn);text-underline-offset:4px}

/* ---------- lá thư ---------- */
.letter-wrap{max-width:40rem;margin:0 auto;padding:56px 20px 24px}
.intro{color:var(--soft);font-size:15px;margin:0 0 32px;font-style:italic}
.sheet-letter{--pad:2em;font-size:19px;padding:2em 1.6em 2em 3em}
.lg:not(.locked) ~ .lg:not(.locked){margin-top:var(--lh)}
.sheet-letter .sep{font-style:normal;text-align:center;font-size:14px;color:var(--soft);letter-spacing:.06em}
.lg.locked{display:none}
.lg.gap{display:block;margin-top:var(--lh)}
.lg.gap > p:not(.sep){display:none}
.gap-link{display:block;text-align:center;font-style:normal;font-size:14px;color:var(--soft)}
.lg.new p{animation:ink 2.6s ease both}
@keyframes ink{from{opacity:0;filter:blur(3px)}to{opacity:1;filter:none}}
.rest{color:var(--soft);font-size:15px;margin:28px 0 0;font-style:italic}
.rest a{color:var(--blue)}

/* ---------- chân trang ---------- */
.foot{color:var(--soft);font-size:13px;text-align:center;padding:72px 24px 40px}
.foot p{margin:2px 0}

/* ---------- điện thoại ---------- */
@media (max-width:720px){
  .bar{padding:10px 16px}
  .nav{gap:14px}
  .mark{font-size:12px;letter-spacing:.14em}
  .hero{grid-template-columns:1fr;gap:36px;padding:36px 24px 16px;text-align:left}
  .cover{width:min(62vw,240px);margin:0 auto}
  .blurb{font-size:18px}
  .ch-big{font-size:100px;top:-30px;right:-4px}
  .reader{padding-top:40px}
  .pager{grid-template-columns:1fr 1fr;grid-template-areas:'pv nx' 'mid mid'}
  .pager .pv{grid-area:pv}.pager .nx{grid-area:nx}.pager .mid{grid-area:mid;text-align:center;padding-top:14px}
  .paper{padding-left:2.3em}
  .sheet-letter{padding:1.6em 1.1em 1.6em 2.5em;font-size:18px}
}
@media (prefers-reduced-motion:reduce){
  .cv-slash line{animation:none;stroke-dashoffset:0}
  .cover::after{animation:none;opacity:1}
  .lg.new p{animation:none}
  .home-letter .paper{transition:none}
}