/* ============================================================
   生日快乐 · 致李 — V3
   叙事型单页：开屏 → 满幅章节 → 横向长卷 → 粘性图文 → 信 → 终章
   ============================================================ */

@font-face{
  font-family:"LiSerif";
  src:url("/assets/fonts/serif-subset.woff2") format("woff2");
  font-weight:400;font-style:normal;font-display:swap;
}

:root{
  --bg:#080706;
  --bg-2:#0f0e0d;
  --fg:#eee9df;
  --fg-2:#b5aea2;
  --fg-3:#6f695f;
  --fg-4:#454039;
  --line:rgba(238,233,223,.16);
  --line-2:rgba(238,233,223,.07);
  --gold:#b5904f;

  --serif:"LiSerif","Songti SC","STSong","Source Han Serif SC","Noto Serif SC","SimSun",serif;
  --sans:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",system-ui,sans-serif;
  --latin:"Helvetica Neue",Helvetica,Arial,sans-serif;

  --gut:clamp(22px,6vw,96px);
  --ease:cubic-bezier(.16,.84,.28,1);
  --ease-out:cubic-bezier(.22,.61,.36,1);
}

*,*::before,*::after{box-sizing:border-box}

html{background:var(--bg);scroll-behavior:smooth;-webkit-text-size-adjust:100%}

body{
  margin:0;background:var(--bg);color:var(--fg);
  font-family:var(--sans);line-height:1.8;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
  overflow-x:hidden;
}

img{display:block;max-width:100%;height:auto}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
::selection{background:var(--gold);color:#080706}

/* ============================================================
   开屏
   ============================================================ */

.intro{
  position:fixed;inset:0;z-index:300;
  background:#080706;
  display:grid;place-items:center;
  transition:opacity .7s var(--ease),visibility .7s;
}
.intro.is-done{opacity:0;visibility:hidden;pointer-events:none}
.intro.is-done .intro-inner{transform:translateY(-16px)}

.intro-inner{
  display:flex;flex-direction:column;align-items:center;gap:clamp(20px,4vh,36px);
  transition:transform 1s var(--ease);
}
.intro-num{
  font-family:var(--latin);font-size:11px;letter-spacing:.5em;
  color:var(--gold);opacity:.75;
}
.intro-name{
  font-family:var(--serif);
  font-size:clamp(64px,13vw,132px);
  line-height:1;letter-spacing:.1em;text-indent:.1em;
  color:var(--fg);
  overflow:hidden;
}
.intro-name span{
  display:block;
  transform:translateY(105%);
  animation:introRise 1.15s var(--ease) .12s forwards;
}
@keyframes introRise{to{transform:translateY(0)}}

.intro-bar{
  width:clamp(120px,18vw,220px);height:1px;
  background:var(--line);overflow:hidden;
}
.intro-bar i{
  display:block;height:100%;width:0;
  background:var(--gold);
  transition:width .5s var(--ease-out);
}

/* ============================================================
   全局装饰
   ============================================================ */

.grain{
  position:fixed;inset:0;z-index:3;pointer-events:none;opacity:.048;
  background-image:radial-gradient(rgba(255,255,255,.85) .5px,transparent .5px);
  background-size:3px 3px;
}

.progress{
  position:fixed;top:0;left:0;right:0;z-index:60;
  height:1px;background:var(--line-2);
}
.progress i{
  display:block;height:100%;width:0;
  background:linear-gradient(to right,transparent,var(--gold));
  transition:width .12s linear;
}

/* 自定义光标 */
.cursor{
  position:fixed;top:0;left:0;z-index:250;
  width:34px;height:34px;margin:-17px 0 0 -17px;
  pointer-events:none;border-radius:50%;
  border:1px solid rgba(238,233,223,.35);
  opacity:0;
  transition:opacity .3s, width .35s var(--ease-out), height .35s var(--ease-out),
             margin .35s var(--ease-out), background .35s var(--ease-out),
             border-color .35s var(--ease-out);
  will-change:transform;
}
.cursor.is-on{opacity:1}
.cursor.is-view{
  width:74px;height:74px;margin:-37px 0 0 -37px;
  background:rgba(181,144,79,.12);
  border-color:rgba(181,144,79,.6);
}
.cursor i{
  position:absolute;inset:0;display:grid;place-items:center;
  font-family:var(--sans);font-size:0;letter-spacing:.1em;
  color:var(--fg);opacity:0;transition:opacity .25s,font-size .25s;
}
.cursor.is-view i{opacity:1;font-size:9px;}

/* 右侧章节导航 */
.rail{
  position:fixed;right:clamp(14px,2.4vw,34px);top:50%;z-index:55;
  transform:translateY(-50%);
  display:flex;flex-direction:column;gap:clamp(12px,2.2vh,22px);
  opacity:0;transition:opacity .6s var(--ease-out);
}
.rail.is-on{opacity:1}
.rail a{
  display:flex;align-items:center;gap:12px;
  text-decoration:none;color:var(--fg-3);
  flex-direction:row-reverse;
}
.rail a i{
  display:block;width:5px;height:5px;border-radius:50%;
  background:currentColor;
  transition:transform .4s var(--ease-out),background .4s;
}
.rail a span{
  font-family:var(--serif);font-size:11px;letter-spacing:.24em;
  white-space:nowrap;opacity:0;transform:translateX(6px);
  transition:opacity .35s var(--ease-out),transform .35s var(--ease-out);
}
.rail a:hover span,.rail a.is-active span{opacity:1;transform:none}
.rail a:hover{color:var(--fg-2)}
.rail a.is-active{color:var(--gold)}
.rail a.is-active i{transform:scale(1.7)}

/* ============================================================
   拆分字动画
   ============================================================ */

.split-word{display:inline-block;overflow:hidden;vertical-align:bottom}
.split-char{
  display:inline-block;
  transform:translateY(110%);
  opacity:0;
  transition:transform 1.1s var(--ease),opacity 1.1s var(--ease);
  transition-delay:calc(var(--i,0) * 90ms);
}
.is-in .split-char,.split-ready .split-char{transform:none;opacity:1}

/* 通用入场 */
[data-reveal]{
  opacity:0;transform:translateY(28px);
  transition:opacity 1.1s var(--ease-out),transform 1.1s var(--ease-out);
  transition-delay:var(--d,0s);
}
[data-reveal].is-in{opacity:1;transform:none}

/* ============================================================
   序 · 首屏
   ============================================================ */

.hero{
  position:relative;
  min-height:100svh;
  display:flex;align-items:flex-end;
  padding:0 0 clamp(90px,13vh,150px);
  overflow:hidden;
}

.hero-media{
  position:absolute;inset:0;z-index:0;
  clip-path:inset(0 0 0 0);
}
.hero-media img{
  width:100%;height:100%;object-fit:cover;object-position:52% 40%;
  filter:brightness(.46) saturate(.78) contrast(1.05);
  transform:scale(1.06);
  animation:heroIn 2.4s var(--ease) forwards;
}
@keyframes heroIn{from{transform:scale(1.14)}to{transform:scale(1.06)}}
.hero-shade{
  position:absolute;inset:0;
  background:
    linear-gradient(to top,rgba(8,7,6,.95) 0%,rgba(8,7,6,.55) 42%,rgba(8,7,6,.22) 72%,rgba(8,7,6,.5) 100%),
    linear-gradient(to right,rgba(8,7,6,.7) 0%,rgba(8,7,6,.1) 60%);
}

.hero-type{
  position:relative;z-index:2;
  width:100%;
  max-width:1500px;
  margin-inline:auto;
  padding-inline:var(--gut);
}

.hero-kicker{
  margin:0 0 clamp(20px,4vh,36px);
  font-size:11.5px;letter-spacing:.46em;text-indent:.46em;
  color:var(--gold);
}

.hero-title{
  margin:0;
  font-family:var(--serif);
  font-weight:400;
  font-size:clamp(58px,13.5vw,180px);
  line-height:1.02;
  letter-spacing:.02em;
  color:var(--fg);
  text-shadow:0 4px 60px rgba(0,0,0,.55);
}
.hero-title .split-char{padding-bottom:.04em}

.hero-sub{
  display:flex;align-items:center;gap:clamp(14px,2.4vw,26px);
  margin-top:clamp(26px,5vh,48px);
  max-width:640px;
}
.hs-line{
  display:block;flex:0 0 clamp(30px,5vw,70px);height:1px;
  background:var(--gold);opacity:.55;
}
.hero-sub p{
  margin:0;
  font-family:var(--serif);
  font-size:clamp(13px,1.35vw,17px);
  line-height:2;
  letter-spacing:.14em;
  color:var(--fg-2);
}

.hero-to{
  position:absolute;
  right:var(--gut);
  bottom:clamp(24px,4vh,44px);
  margin:0;
  font-family:var(--serif);
  font-size:clamp(12px,1.1vw,14px);
  letter-spacing:.4em;
  color:var(--fg-3);
}

.hero-scroll{
  position:absolute;
  left:50%;bottom:clamp(22px,4vh,40px);
  transform:translateX(-50%);
  z-index:3;
  display:flex;flex-direction:column;align-items:center;gap:14px;
  text-decoration:none;
  color:var(--fg-3);
  transition:color .4s var(--ease-out);
}
.hero-scroll:hover{color:var(--fg-2)}
.hero-scroll span{font-size:10px;letter-spacing:.42em;text-indent:.42em}
.hero-scroll i{
  display:block;width:1px;height:58px;overflow:hidden;position:relative;
  background:var(--line-2);
}
.hero-scroll i::after{
  content:"";position:absolute;inset:0;background:var(--fg-2);
  animation:cueRun 2.6s var(--ease-out) infinite;
}
@keyframes cueRun{
  0%{transform:translateY(-100%)}
  60%,100%{transform:translateY(100%)}
}

/* ============================================================
   章节共用
   ============================================================ */

main{position:relative;z-index:4}

.ch-head{
  display:flex;align-items:center;gap:clamp(12px,2vw,24px);
}
.ch-no{
  font-family:var(--latin);font-size:10.5px;letter-spacing:.2em;
  color:var(--gold);
}
.ch-line{display:block;width:clamp(26px,5vw,56px);height:1px;background:var(--line)}
.ch-label{
  font-family:var(--serif);font-size:clamp(11px,1.1vw,13px);
  letter-spacing:.36em;text-indent:.36em;color:var(--fg-3);
}

/* ============================================================
   01 · 满幅章节
   ============================================================ */

.chapter--bleed{
  position:relative;
  height:clamp(560px,100svh,1000px);
  overflow:hidden;
}

.ch-media{
  position:absolute;inset:0;z-index:0;
  overflow:hidden;
}
.ch-media img{
  width:100%;height:120%;
  object-fit:cover;object-position:50% 30%;
  filter:brightness(.52) saturate(.82) contrast(1.04);
  will-change:transform;
}

.ch-overlay{
  position:relative;z-index:2;
  height:100%;
  display:flex;flex-direction:column;justify-content:space-between;
  max-width:1500px;
  margin-inline:auto;
  padding:clamp(40px,8vh,90px) var(--gut);
  background:linear-gradient(to bottom,rgba(8,7,6,.6),transparent 30%,transparent 62%,rgba(8,7,6,.75));
}

.ch-big{
  position:absolute;
  left:var(--gut);
  bottom:clamp(40px,7vh,80px);
  margin:0;
  font-family:var(--serif);
  font-weight:400;
  font-size:clamp(110px,26vw,340px);
  line-height:.82;
  letter-spacing:.04em;
  color:transparent;
  -webkit-text-stroke:1px rgba(238,233,223,.3);
  pointer-events:none;
  user-select:none;
}

.ch-quote{
  align-self:flex-end;
  margin:0;
  max-width:min(30em,88%);
  text-align:right;
  font-family:var(--serif);
  font-size:clamp(15px,1.7vw,22px);
  line-height:2.1;
  letter-spacing:.14em;
  color:var(--fg);
  text-shadow:0 2px 24px rgba(0,0,0,.6);
  position:relative;z-index:3;
}

/* ============================================================
   02 · 横向长卷
   ============================================================ */

.hsec{
  position:relative;
  height:260vh;
  background:var(--bg-2);
}
.hsec-pin{
  position:sticky;top:0;
  height:100svh;
  overflow:hidden;
  display:flex;align-items:center;
}
.hsec-track{
  display:flex;align-items:center;
  gap:clamp(30px,5.5vw,110px);
  height:100%;
  padding-inline:var(--gut);
  width:max-content;
  will-change:transform;
}

.hpanel{
  flex:0 0 auto;
  height:100%;
  display:flex;flex-direction:column;justify-content:center;
  margin:0;
}

.hpanel--title{
  flex:0 0 auto;
  width:min(86vw,780px);
  justify-content:center;
  gap:clamp(20px,3vh,34px);
}
.hp-title{
  margin:0;
  font-family:var(--serif);
  font-weight:400;
  font-size:clamp(36px,5.6vw,84px);
  line-height:1.28;
  letter-spacing:.06em;
  color:var(--fg);
  white-space:nowrap;
}
.hp-title span{display:block}
.hp-note{
  margin:0;
  font-size:11px;letter-spacing:.36em;color:var(--fg-3);
}

.hpanel--img{
  width:auto;
  justify-content:center;
}
.hpanel--img .photo-btn{
  display:block;
  height:min(74svh,860px);
  aspect-ratio:2/3;
  cursor:zoom-in;
  position:relative;
  overflow:hidden;
  box-shadow:0 40px 90px -30px rgba(0,0,0,.95);
}
.hpanel--img img{
  height:100%;width:auto;
  object-fit:cover;
  transition:filter .6s var(--ease-out),transform 1.4s var(--ease);
}
.hpanel--img .photo-btn::after{
  content:"查看原图";
  position:absolute;left:0;right:0;bottom:0;
  padding:clamp(16px,3vh,30px);
  font-size:11px;letter-spacing:.3em;color:var(--fg);
  background:linear-gradient(to top,rgba(8,7,6,.85),transparent);
  opacity:0;transform:translateY(8px);
  transition:opacity .45s var(--ease-out),transform .45s var(--ease-out);
}
.hpanel--img .photo-btn:hover::after{opacity:1;transform:none}

.hpanel--img figcaption{
  display:flex;align-items:baseline;gap:12px;
  margin-top:clamp(14px,2vh,22px);
  font-family:var(--serif);font-size:12.5px;
  letter-spacing:.22em;color:var(--fg-3);
}
.hpanel--img figcaption span{color:var(--gold);font-size:11px}

/* 无 JS / 移动端：退化为纵向 */
.hsec.is-flat{height:auto}
.hsec.is-flat .hsec-pin{position:relative;height:auto;display:block;padding-block:clamp(60px,12vh,110px)}
.hsec.is-flat .hsec-track{
  flex-direction:column;align-items:stretch;
  height:auto;gap:clamp(30px,7vw,56px);
  transform:none!important;
}
.hsec.is-flat .hpanel{width:100%;height:auto}
.hsec.is-flat .hsec-track{width:auto}
.hsec.is-flat .hpanel--img .photo-btn{height:auto;aspect-ratio:auto}
.hsec.is-flat .hpanel--img img{width:100%;height:auto}
.hsec.is-flat .hp-note{display:none}

/* ============================================================
   03 · 粘性图文
   ============================================================ */

.sticky{
  position:relative;
  display:grid;
  grid-template-columns:1.15fr .85fr;
  align-items:center;
  gap:clamp(24px,4vw,70px);
  min-height:100svh;
  padding:clamp(70px,12vh,130px) var(--gut);
  max-width:1500px;
  margin-inline:auto;
}

.sticky-media{overflow:hidden}
.sticky-media img{
  width:100%;
  filter:brightness(.86) saturate(.9);
  will-change:transform;
}

.sticky-copy{
  position:sticky;
  top:34vh;
  align-self:start;
}
.sc-title{
  margin:clamp(20px,3vh,30px) 0 clamp(18px,3vh,28px);
  font-family:var(--serif);
  font-weight:400;
  font-size:clamp(40px,5.4vw,82px);
  line-height:1.14;
  letter-spacing:.08em;
  color:var(--fg);
}
.sc-text{
  margin:0;
  font-family:var(--serif);
  font-size:clamp(14px,1.35vw,17.5px);
  line-height:2.15;
  letter-spacing:.12em;
  color:var(--fg-2);
}
.sc-link{
  display:inline-flex;align-items:center;gap:10px;
  margin-top:clamp(26px,4vh,40px);
  font-size:12px;letter-spacing:.26em;color:var(--fg-3);
  border-bottom:1px solid var(--line);
  padding-bottom:6px;
  transition:color .35s var(--ease-out),border-color .35s;
}
.sc-link:hover{color:var(--fg);border-color:var(--gold)}
.sc-link span{transition:transform .35s var(--ease-out)}
.sc-link:hover span{transform:translate(3px,-3px)}

/* ============================================================
   04 · 信
   ============================================================ */

.letter{
  padding:clamp(90px,18vh,190px) var(--gut);
  background:var(--bg-2);
  border-block:1px solid var(--line-2);
}
.letter-wrap{
  max-width:820px;
  margin-inline:auto;
}

.letter-title{
  margin:clamp(28px,6vh,56px) 0 clamp(40px,8vh,76px);
  font-family:var(--serif);
  font-weight:400;
  font-size:clamp(32px,4.6vw,68px);
  line-height:1.35;
  letter-spacing:.06em;
  color:var(--fg);
}
.letter-title .split-char{padding-bottom:.06em}

.letter-body p{
  margin:0 0 clamp(18px,3.4vh,30px);
  font-family:var(--serif);
  font-size:clamp(15px,1.55vw,20px);
  line-height:2.25;
  letter-spacing:.1em;
  color:var(--fg-2);
}
.letter-body p:last-child{color:var(--fg)}

.letter-sign{
  margin:clamp(40px,7vh,70px) 0 0;
  font-family:var(--serif);
  font-size:13px;letter-spacing:.34em;
  color:var(--fg-3);
}

/* ============================================================
   05 · 终章
   ============================================================ */

.finale{
  position:relative;
  min-height:100svh;
  display:flex;flex-direction:column;
  justify-content:center;align-items:center;
  text-align:center;
  padding:clamp(90px,16vh,170px) var(--gut) clamp(40px,8vh,80px);
  overflow:hidden;
  background:
    radial-gradient(ellipse at 50% 40%,rgba(181,144,79,.09),transparent 62%),
    var(--bg);
}

.finale-particles{position:absolute;inset:0;pointer-events:none;overflow:hidden}
.mote{
  position:absolute;bottom:-10px;
  width:2px;height:2px;border-radius:50%;
  background:var(--gold);
  opacity:0;
  animation:floatUp linear infinite;
}
@keyframes floatUp{
  0%{transform:translate3d(0,0,0) scale(.6);opacity:0}
  12%{opacity:var(--o,.5)}
  80%{opacity:var(--o,.5)}
  100%{transform:translate3d(var(--dx,20px),-110vh,0) scale(1);opacity:0}
}

.finale-inner{position:relative;z-index:2}

.finale-kicker{
  margin:0 0 clamp(26px,5vh,46px);
  font-size:11px;letter-spacing:.46em;text-indent:.46em;
  color:var(--gold);
}

.finale-title{
  margin:0;
  font-family:var(--serif);
  font-weight:400;
  font-size:clamp(56px,12vw,168px);
  line-height:1.06;
  letter-spacing:.04em;
  color:var(--fg);
}
.finale-title .split-char{padding-bottom:.05em}

.finale-wish{
  margin:clamp(30px,6vh,56px) 0 0;
  font-family:var(--serif);
  font-size:clamp(13px,1.3vw,16px);
  letter-spacing:.28em;
  color:var(--fg-2);
}

.finale-foot{
  position:absolute;
  left:var(--gut);right:var(--gut);bottom:clamp(22px,4vh,40px);
  display:flex;justify-content:space-between;gap:16px;
  font-family:var(--latin);font-size:10.5px;letter-spacing:.3em;
  color:var(--fg-4);
}
.finale-top{
  font-family:var(--sans);font-size:11px;letter-spacing:.24em;
  color:var(--fg-3);
  transition:color .35s var(--ease-out);
}
.finale-top:hover{color:var(--gold)}

/* ============================================================
   灯箱
   ============================================================ */

.lightbox{
  position:fixed;inset:0;z-index:200;
  display:flex;align-items:center;justify-content:center;
  padding:clamp(16px,4vw,56px);
  background:rgba(5,4,3,.97);
  -webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);
  animation:lbIn .4s var(--ease-out);
}
.lightbox[hidden]{display:none}
@keyframes lbIn{from{opacity:0}to{opacity:1}}

.lb-figure{margin:0;display:flex;flex-direction:column;align-items:center;gap:20px;max-width:100%;max-height:100%}
.lb-figure img{
  width:auto;height:auto;
  max-width:calc(100vw - clamp(32px,8vw,112px));
  max-height:calc(100svh - clamp(112px,18vh,180px));
  object-fit:contain;
  box-shadow:0 30px 90px rgba(0,0,0,.75);
}
.lb-figure figcaption{
  font-family:var(--serif);font-size:13px;letter-spacing:.24em;color:var(--fg-2);
}
.lb-close{
  position:absolute;top:clamp(12px,2.4vw,26px);right:clamp(14px,2.6vw,30px);
  width:46px;height:46px;font-size:30px;line-height:1;color:var(--fg-3);
  transition:color .3s,transform .35s var(--ease-out);
}
.lb-close:hover{color:var(--fg);transform:rotate(90deg)}
.lb-hint{
  position:absolute;bottom:clamp(14px,2.4vw,24px);
  font-family:var(--latin);font-size:10.5px;letter-spacing:.26em;color:var(--fg-4);
}

/* ============================================================
   减少动效
   ============================================================ */

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .split-char{transform:none;opacity:1;transition:none}
  [data-reveal]{opacity:1;transform:none;transition:none}
  .hero-media img,.intro-name span{animation:none}
  .mote,.hero-scroll i::after{animation:none;display:none}
  .intro{transition:none}
  *{animation-duration:.01ms!important;transition-duration:.01ms!important}
}

/* ============================================================
   响应式
   ============================================================ */

@media (max-height:760px){
  .hpanel--img .photo-btn{height:calc(100svh - 130px)}
  .hpanel--img figcaption{margin-top:10px}
  .hp-title{font-size:clamp(30px,4.2vw,60px)}
}

@media (max-width:1100px){
  .sticky{grid-template-columns:1fr;gap:clamp(30px,6vw,50px)}
  .sticky-copy{position:static;top:auto}
}

@media (max-width:820px){
  .rail{display:none}
  .cursor{display:none}

  .hero{align-items:flex-end;padding-bottom:clamp(150px,20vh,190px)}
  .hero-to{display:none}
  .hero-sub{flex-direction:column;align-items:flex-start;gap:14px}
  .hs-line{flex:none;width:40px;height:1px}
  .hero-scroll{bottom:clamp(20px,3.5vh,30px)}
  .hero-scroll i{height:42px}

  .ch-big{font-size:clamp(92px,32vw,180px);opacity:.9}
  .ch-quote{text-align:left;align-self:flex-start;max-width:100%}
  .ch-overlay{justify-content:flex-start;gap:auto}

  .hsec{height:auto}
  .hsec-pin{position:relative;height:auto;display:block;padding-block:clamp(50px,10vh,90px);overflow:visible}
  .hsec-track{
    flex-direction:column;align-items:stretch;
    height:auto;width:auto;gap:clamp(26px,6vw,44px);transform:none!important;
  }
  .hpanel{width:100%;height:auto}
  .hpanel--img .photo-btn{height:auto;aspect-ratio:auto}
  .hpanel--img img{width:100%;height:auto}
  .hp-note{display:none}

  .sticky{padding-block:clamp(60px,10vh,100px)}

  .letter-title{letter-spacing:.04em}
  .finale-foot{font-size:9.5px;letter-spacing:.2em}
}

@media (max-width:520px){
  .hero-title{letter-spacing:0}
  .ch-big{letter-spacing:0}
  .letter-body p{letter-spacing:.06em}
  .finale-wish{letter-spacing:.16em}
}