/* ============================================================
   高简宣传页 v4 · 建筑制图风 · 黑白线条
   三级响应式(手机/平板/桌面) · 移动优先 · 桌面端滚动reveal
   ============================================================ */

:root{
  --ink:#111; --ink-soft:#2a2a2a; --ink-muted:#6b6b6b;
  --paper:#fefefb; --paper-warm:#f5f2ea;
  --hairline:#d6d1c7; --hairline-pale:#ece8de;
  --accent:#b91c1c;
  --font-serif:"Noto Serif SC","Songti SC","SimSun","STSong",serif;
  --font-sans:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;
  --font-mono:ui-monospace,"SF Mono",Menlo,Consolas,monospace;
  --max:680px;
  --nav-h:54px;
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
body{
  font-family:var(--font-sans);font-size:16px;line-height:1.7;color:var(--ink);
  background:var(--paper);position:relative;overflow-x:hidden;
}
/* 蓝图网格底纹(极淡,全局) */
body::before{
  content:'';position:fixed;inset:0;z-index:0;pointer-events:none;
  background-image:
    linear-gradient(rgba(17,17,17,.02) 1px,transparent 1px),
    linear-gradient(90deg,rgba(17,17,17,.02) 1px,transparent 1px);
  background-size:48px 48px;
}
body>*{position:relative;z-index:1}
::selection{background:var(--ink);color:var(--paper)}

/* ---- Typography ---- */
.t-hero{font:700 clamp(2.2rem,9vw,4rem)/1.05 var(--font-serif);letter-spacing:.005em}
.t-headline{font:700 clamp(1.45rem,5vw,2.1rem)/1.2 var(--font-serif)}
.t-title{font:600 1.15rem/1.35 var(--font-serif)}
.t-body{font:1rem/1.8 var(--font-sans);color:var(--ink-soft)}
.t-body-lg{font:1.05rem/1.85 var(--font-serif);color:var(--ink-soft)}
.t-label{
  font:600 .68rem/1 var(--font-mono);letter-spacing:.18em;text-transform:uppercase;
  color:var(--ink-muted);
}
.t-label::before{content:'—  '}
.t-label.t-center{text-align:center}
.t-label.t-center::after{content:'  —'}
.t-muted{color:var(--ink-muted)}
.t-sm{font-size:.85rem}
.t-center{text-align:center}
.t-num{font:700 2.8rem/1 var(--font-serif)}
.t-strike{text-decoration:line-through;color:var(--ink-muted)}
.arrow{font-family:var(--font-sans);color:var(--ink-muted)}

/* ---- Layout ---- */
.wrap{max-width:var(--max);margin:0 auto;padding:0 1.25rem}
.sec{padding:4rem 0}
.sec-sm{padding:2.75rem 0}
.sec-warm{background:var(--paper-warm)}
.sp-xxs{margin-bottom:.25rem}.sp-xs{margin-bottom:.5rem}
.sp-sm{margin-bottom:1rem}.sp{margin-bottom:1.5rem}
.sp-lg{margin-bottom:2.5rem}.sp-xl{margin-bottom:4rem}

/* ---- Crop marks(建筑制图十字角标) ---- */
.crop{position:relative}
.crop::before,.crop::after{
  content:'';position:absolute;width:9px;height:9px;pointer-events:none;
  border:1px solid var(--ink);
}
.crop::before{top:-1px;left:-1px;border-right:0;border-bottom:0}
.crop::after{bottom:-1px;right:-1px;border-left:0;border-top:0}

/* ---- Nav(与主站 gj-nav 统一) ---- */
.nav{
  position:fixed;top:0;left:0;right:0;z-index:100;height:var(--nav-h);
  display:flex;align-items:center;justify-content:space-between;
  padding:0 1.25rem;padding-top:env(safe-area-inset-top);
  background:rgba(254,254,251,.86);
  backdrop-filter:blur(12px) saturate(1.2);-webkit-backdrop-filter:blur(12px) saturate(1.2);
  border-bottom:1px solid var(--hairline-pale);
}
.nav-brand{
  font:500 1.35rem/1 var(--font-serif);color:var(--ink);text-decoration:none;
  letter-spacing:.02em;
}
.nav-brand span{position:relative}
.nav-brand span::after{
  content:'';position:absolute;left:0;bottom:.08em;
  width:100%;height:2px;background:var(--ink);
}
.nav-right{display:flex;align-items:center;gap:1rem}
.nav-cta{
  background:var(--ink);color:var(--paper)!important;
  padding:7px 16px;font:600 .72rem/1 var(--font-sans);letter-spacing:.04em;
  text-decoration:none;transition:background .15s;white-space:nowrap;
}
.nav-cta:hover{background:var(--ink-soft)}
.nav-links{display:flex;gap:1.1rem;align-items:center}
.nav-links a{
  font-size:.78rem;color:var(--ink-muted);text-decoration:none;
  padding-bottom:2px;border-bottom:1px solid transparent;
  transition:color .15s,border-color .15s;white-space:nowrap;
}
.nav-links a:hover,.nav-links a.on{color:var(--ink);border-bottom-color:var(--ink)}

.nav-burger{
  display:none;flex-direction:column;gap:4px;
  width:24px;background:none;border:none;cursor:pointer;padding:6px 0;margin-left:.75rem;
}
.nav-burger span{display:block;height:1.5px;background:var(--ink);transition:transform .25s,opacity .2s}
.nav-burger.open span:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.nav-burger.open span:nth-child(2){opacity:0}
.nav-burger.open span:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}

/* ---- Buttons ---- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.5rem;
  padding:15px 40px;font:600 .95rem var(--font-sans);letter-spacing:.03em;
  text-decoration:none;border:none;cursor:pointer;transition:all .2s;
  position:relative;
}
.btn-primary{background:var(--ink);color:var(--paper)}
.btn-primary:hover{background:var(--ink-soft);transform:translateY(-1px)}
.btn-primary:active{transform:translateY(0)}
.btn-lg{padding:17px 56px;font-size:1.05rem}
.btn-block{width:100%}
.btn:disabled{opacity:.6;cursor:not-allowed;transform:none}

/* ---- Hero ---- */
.hero{padding:5rem 0 3rem;text-align:center;position:relative;overflow:hidden}
.hero::after{
  content:'';position:absolute;bottom:0;left:50%;transform:translateX(-50%);
  width:1px;height:56px;background:var(--hairline);
}
.hero-badge{
  display:inline-block;padding:5px 18px;border:1px solid var(--hairline);
  font:600 .66rem/1 var(--font-mono);letter-spacing:.14em;
  color:var(--ink-muted);margin-bottom:1.25rem;
}
.hero-tagline{
  font:1.05rem/1.65 var(--font-serif);color:var(--ink-soft);
  max-width:420px;margin:0 auto 1.5rem;
}
.hero-meta{display:flex;gap:1.25rem;justify-content:center;flex-wrap:wrap;margin-bottom:2rem}
.hero-meta-item{
  display:flex;align-items:center;gap:6px;
  font:.8rem/1.4 var(--font-mono);color:var(--ink-muted);letter-spacing:.02em;
}
.hero-meta-item svg{width:14px;height:14px;opacity:.5;flex-shrink:0}

/* hero 入场动画(所有端) */
.hero-badge,.hero .t-hero,.hero .hero-tagline,.hero .hero-meta,.hero .btn{
  opacity:0;transform:translateY(14px);
  animation:heroIn .7s cubic-bezier(.2,.7,.2,1) forwards;
}
.hero .t-hero{animation-delay:.08s}
.hero .hero-tagline{animation-delay:.18s}
.hero .hero-meta{animation-delay:.28s}
.hero .btn{animation-delay:.38s}
@keyframes heroIn{to{opacity:1;transform:translateY(0)}}

/* ---- Pain Points ---- */
.pain-item{
  display:flex;gap:1.25rem;padding:1.25rem 0;
  border-bottom:1px solid var(--hairline-pale);align-items:baseline;
}
.pain-item:first-child{border-top:1px solid var(--hairline-pale)}
.pain-num{
  font:700 1.4rem/1 var(--font-mono);color:var(--hairline);
  flex-shrink:0;width:34px;letter-spacing:.02em;
}
.pain-text{font:1rem/1.5 var(--font-serif)}

/* ---- Video ---- */
.video-sec{display:flex;flex-direction:column;align-items:center;gap:1.75rem}
.video-wrap{
  position:relative;width:62%;max-width:300px;flex-shrink:0;
  border:1px solid var(--hairline);
  background:#000;overflow:hidden;
  /* 视频原生比例 448:960（含底部字幕）。盒子跟着视频走，海报去适配盒子。
     JS 读到真实 metadata 后会把这个值改成实际尺寸，永久自校准。 */
  aspect-ratio:448/960;
}
/* 视频与海报都绝对铺满盒子 */
.video-wrap video,
.video-wrap .video-poster-cover{
  position:absolute;inset:0;width:100%;height:100%;display:block;
}
/* 视频 contain：盒子=视频比例时不裁切，整帧（含字幕）完整可见 */
.video-wrap video{object-fit:contain;background:#000;display:none}
/* 海报 cover：主动适配视频盒子（海报随视频变，不是反过来） */
.video-poster-cover{object-fit:cover;cursor:pointer}
.video-wrap.is-playing video{display:block}
.video-wrap.is-playing .video-poster-cover{display:none}
.video-overlay{
  position:absolute;inset:0;display:flex;align-items:center;justify-content:center;
  background:rgba(0,0,0,.22);cursor:pointer;transition:opacity .35s;
}
.video-overlay::after{
  content:'';position:absolute;inset:8px;border:1px solid rgba(255,255,255,.18);pointer-events:none;
}
.video-play{
  width:62px;height:62px;border-radius:50%;
  background:rgba(254,254,251,.94);border:none;cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  transition:transform .2s,box-shadow .2s;
  box-shadow:0 4px 20px rgba(0,0,0,.25);
}
.video-play:hover{transform:scale(1.06);box-shadow:0 6px 26px rgba(0,0,0,.32)}
.video-play::after{
  content:'';display:block;width:0;height:0;
  border-style:solid;border-width:11px 0 11px 19px;
  border-color:transparent transparent transparent var(--ink);
  margin-left:4px;
}
.video-overlay.playing{opacity:0;pointer-events:none}
/* 播放中暂停提示(悬停) */
.video-wrap.is-playing:hover .video-overlay{opacity:1;pointer-events:auto;background:rgba(0,0,0,.35)}
.video-wrap.is-playing .video-play::after{
  border-width:0 6px 0 6px;border-color:transparent transparent transparent transparent;
  border-left-color:var(--ink);border-right-color:var(--ink);margin-left:0;
}

.video-card{
  display:block;padding:1.5rem;border:1px solid var(--hairline);
  max-width:300px;width:100%;text-align:left;
}
.video-card .vc-item{padding:.85rem 0;border-bottom:1px solid var(--hairline-pale)}
.video-card .vc-item:first-child{padding-top:0}
.video-card .vc-item:last-child{border-bottom:0;padding-bottom:0}
.video-card .vc-label{font:.64rem/1 var(--font-mono);color:var(--ink-muted);letter-spacing:.1em;margin-bottom:4px;text-transform:uppercase}
.video-card .vc-val{font:.88rem/1.45 var(--font-serif)}

/* ---- Poster ---- */
.poster-block{width:100%;max-width:480px;margin:0 auto;border:1px solid var(--hairline)}
.poster-block img{width:100%;height:auto;display:block}

/* ---- Instructor ---- */
.inst{display:flex;gap:1.25rem;align-items:flex-start;padding:1.5rem;border:1px solid var(--hairline)}
.inst-avatar{
  width:72px;height:72px;flex-shrink:0;background:var(--hairline-pale);
  display:flex;align-items:center;justify-content:center;
  font:1.8rem var(--font-serif);color:var(--ink-muted);overflow:hidden;
}
.inst-avatar img{width:100%;height:100%;object-fit:cover}
.inst-name{font:600 1.05rem var(--font-serif);margin-bottom:3px}
.inst-title{font:.8rem/1.4 var(--font-mono);color:var(--ink-muted);margin-bottom:.6rem;letter-spacing:.02em}
.inst-desc{font-size:.92rem;line-height:1.7;color:var(--ink-soft)}

/* ---- Benefits ---- */
.benefits{display:flex;flex-direction:column;gap:.75rem}
.benefit{
  display:flex;gap:1rem;padding:1.25rem;
  border:1px solid var(--hairline-pale);transition:border-color .2s,background .2s;
}
.benefit:hover{border-color:var(--hairline);background:var(--paper)}
.benefit-icon{
  width:38px;height:38px;flex-shrink:0;
  display:flex;align-items:center;justify-content:center;
  border:1px solid var(--hairline);font:1.05rem var(--font-serif);color:var(--ink-muted);
}
.benefit-text{font-size:.92rem;line-height:1.55}
.benefit-text strong{display:block;font-size:.96rem;font-weight:600;margin-bottom:3px;color:var(--ink)}

/* ---- Pricing ---- */
.price-header{text-align:center}
.price-original{font:1rem var(--font-serif);text-decoration:line-through;color:var(--ink-muted)}
.price-grid{display:flex;flex-direction:column;gap:.75rem}
.price-card{
  text-align:center;padding:1.75rem 1.5rem;border:1px solid var(--hairline);
  transition:all .2s;background:var(--paper);
}
.price-card:hover{border-color:var(--ink-soft)}
.price-card.feat{border-color:var(--ink);border-width:2px;position:relative}
.price-card.feat::before{
  content:'推荐';position:absolute;top:-10px;left:50%;transform:translateX(-50%);
  background:var(--ink);color:var(--paper);
  padding:3px 16px;font:.64rem/1 var(--font-mono);letter-spacing:.1em;font-weight:600;
}
.price-label{font:1rem var(--font-serif);margin-bottom:.75rem}
.price-amt{font:700 2.6rem/1 var(--font-serif)}
.price-amt small{font-size:1rem;font-weight:400;color:var(--ink-muted)}
.price-note{font:.76rem/1.4 var(--font-mono);color:var(--ink-muted);margin-top:.5rem;letter-spacing:.02em}

/* ---- Form ---- */
.form-row{margin-bottom:1.1rem}
.form-label{display:block;font:.78rem/1 var(--font-mono);font-weight:600;color:var(--ink-soft);margin-bottom:6px;letter-spacing:.04em;text-transform:uppercase}
.form-label .req{color:var(--accent)}
.form-input{
  width:100%;padding:13px 15px;font:1rem var(--font-sans);color:var(--ink);
  background:var(--paper);border:1px solid var(--hairline);
  -webkit-appearance:none;border-radius:0;transition:border-color .15s,background .15s;
}
.form-input:focus{outline:none;border-color:var(--ink);background:var(--paper-warm)}
.form-input::placeholder{color:#b5b0a6}
textarea.form-input{min-height:96px;resize:vertical;line-height:1.6}
.form-err{color:var(--accent);font:.76rem/1.3 var(--font-sans);margin-top:4px;min-height:1px}
.form-err-lg{color:var(--accent);font:.82rem/1.4 var(--font-sans);margin-bottom:.75rem;padding:8px 12px;border-left:2px solid var(--accent);background:rgba(185,28,28,.04);display:none}
.form-err-lg.show{display:block}
.form-ok{text-align:center;padding:2.5rem 1.5rem;border:1px solid var(--hairline);background:var(--paper-warm)}
.form-ok-icon{font-size:2.5rem;margin-bottom:1rem;color:var(--ink)}
.form-ok h3{font:1.15rem var(--font-serif);margin-bottom:.5rem}

/* ---- Info Row ---- */
.info-row{display:flex;gap:1rem;padding:1.1rem 0;border-bottom:1px solid var(--hairline-pale);align-items:baseline}
.info-row:first-child{border-top:1px solid var(--hairline-pale)}
.info-icon{font-size:1.05rem;flex-shrink:0;width:26px;text-align:center}
.info-text{font:1rem/1.5 var(--font-serif)}

/* ---- Events Page ---- */
.events-hero{padding:5rem 0 2rem;text-align:center}
.event-card{
  display:flex;gap:1rem;padding:1.25rem;border:1px solid var(--hairline-pale);
  text-decoration:none;color:inherit;transition:all .2s;
}
.event-card:hover{border-color:var(--ink);transform:translateY(-2px)}
.event-card-thumb{width:64px;height:64px;flex-shrink:0;overflow:hidden;background:var(--hairline-pale)}
.event-card-thumb img{width:100%;height:100%;object-fit:cover}
.event-card-info{flex:1}
.event-card-info strong{display:block;font-size:.96rem;margin-bottom:3px;font-family:var(--font-serif)}
.event-card-info .meta{font:.76rem/1.4 var(--font-mono);color:var(--ink-muted);letter-spacing:.02em}
.event-tag{
  display:inline-block;padding:2px 10px;font:.62rem/1 var(--font-mono);font-weight:600;
  letter-spacing:.1em;border:1px solid var(--hairline);margin-bottom:.5rem;text-transform:uppercase;
}
.event-tag.active{border-color:var(--ink);background:var(--ink);color:var(--paper)}
.past-link{
  display:flex;justify-content:space-between;align-items:center;gap:1rem;
  padding:.85rem 0;border-bottom:1px solid var(--hairline-pale);
  min-height:44px;
  text-decoration:none;color:inherit;transition:opacity .15s;
}
.past-link:hover{opacity:.55}
.past-link .date{font:.78rem/1 var(--font-mono);color:var(--ink-muted);min-width:110px;letter-spacing:.02em}
.past-link .ttl{flex:1;font:.92rem/1.4 var(--font-serif)}
.search-wrap{position:relative;max-width:380px;margin:0 auto 2rem}
.search-wrap input{padding-left:38px}
.search-wrap .ico{position:absolute;left:12px;top:50%;transform:translateY(-50%);color:var(--ink-muted);font-size:.9rem;pointer-events:none}

/* ---- Footer ---- */
.foot{
  text-align:center;padding:2.5rem 1.25rem;padding-bottom:calc(2.5rem + env(safe-area-inset-bottom));
  border-top:1px solid var(--hairline);color:var(--ink-muted);font:.76rem/1.6 var(--font-mono);letter-spacing:.02em;
}
.foot a{color:var(--ink-muted);text-decoration:none}
.foot a:hover{color:var(--ink)}

/* ---- Scroll Reveal(仅桌面) ---- */
@media(min-width:1024px){
  .rev{opacity:0;transform:translateY(22px);transition:opacity .65s cubic-bezier(.2,.7,.2,1),transform .65s cubic-bezier(.2,.7,.2,1)}
  .rev.on{opacity:1;transform:translateY(0)}
}

/* ============ 平板 (768-1023) ============ */
@media(min-width:768px){
  :root{--max:760px}
  .hero{padding:5.5rem 0 3.5rem}
  .pain-list{display:grid;grid-template-columns:1fr;gap:0}
  .benefits{display:grid;grid-template-columns:1fr 1fr;gap:.75rem}
  .price-grid{flex-direction:row}
  .price-card{flex:1}
  .inst{max-width:560px;margin:0 auto}
  .poster-block{max-width:420px}
  .video-sec{flex-direction:row;justify-content:center;align-items:flex-start;gap:2rem}
  .video-wrap{width:240px;margin:0}
  .video-card{display:block}
}

/* ============ 桌面 (>=1024) ============ */
@media(min-width:1024px){
  :root{--max:820px}
  .hero{padding:7rem 0 5rem}
  .hero-tagline{font-size:1.15rem}
  .benefit{padding:1.5rem}
  .benefit-text{font-size:.96rem}
  .video-sec{flex-direction:row;justify-content:center;align-items:flex-start;gap:3rem}
  .video-wrap{width:280px;margin:0}
  .video-card{display:block}
  .poster-block{max-width:460px}
}

/* ============ 手机 (<=767) ============ */
@media(max-width:767px){
  .nav-burger{display:flex;width:44px;height:44px;align-items:center;justify-content:center;padding:0;margin-left:.5rem}
  .nav-burger span{width:22px}
  .nav-links{
    position:absolute;top:calc(var(--nav-h) - 1px);left:0;right:0;
    flex-direction:column;align-items:flex-start;gap:0;
    padding:.5rem 1.25rem 1rem;
    background:rgba(254,254,251,.98);
    backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);
    border-bottom:1px solid var(--hairline-pale);
    transform:translateY(-6px);opacity:0;pointer-events:none;
    transition:opacity .22s,transform .22s;
  }
  .nav-links.open{transform:translateY(0);opacity:1;pointer-events:auto}
  .nav-links a{font-size:.9rem;min-height:44px;display:flex;align-items:center;width:100%;padding:6px 0}
  .nav-cta{min-height:44px;display:inline-flex;align-items:center;padding:8px 18px}
}
@media(max-width:480px){
  .sec{padding:2.75rem 0}
  .sec-sm{padding:2rem 0}
  .hero{padding:4.5rem 0 2.5rem}
  .hero-meta{gap:.9rem}
  .pain-text{font-size:.93rem}
  .btn-lg{padding:15px 36px;font-size:.98rem}
  .price-amt{font-size:2.3rem}
  .inst{flex-direction:column;align-items:center;text-align:center}
  .video-wrap{width:62%}
  .events-hero .t-hero{font-size:clamp(1.6rem,7vw,2.4rem)}
}

/* 减弱动画(用户偏好) */
@media(prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important;scroll-behavior:auto!important}
  .rev{opacity:1;transform:none}
  .hero-badge,.hero .t-hero,.hero .hero-tagline,.hero .hero-meta,.hero .btn{opacity:1;transform:none}
}