/* 人工智慧論壇 · 活動頁共用樣式（沿用「講座通」設計稿，白底） */
:root{
  /* 沿用"講座通"設計稿色板：沉穩深青 + 暖色點綴；頁面底色按要求用白色 */
  --brand:#17606b; --brand-dark:#0f4a53; --brand-soft:#e3f0f1; --brand-mid:#b9d8db;
  --gold:#a8630f; --gold-soft:#fbefd9;
  --bg:#ffffff; --surface:#fffefb; --surface-2:#f2ece0; --line:#e5decf; --line-strong:#cdc4b0;
  --text:#23302f; --muted:#5a6766; --danger:#b0352b; --ok:#2a7347; --ok-soft:#e0f1e6; --focus:#2a6fdb;
  --radius:14px; --shadow:0 1px 2px rgba(35,48,47,.06),0 6px 18px rgba(35,48,47,.06);
  --font:system-ui,-apple-system,"PingFang TC","Microsoft JhengHei","Noto Sans TC","PingFang SC",sans-serif;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:var(--font);font-size:16px;line-height:1.65;color:var(--text);background:var(--bg)}
h1,h2,h3{line-height:1.3;margin:0 0 .5em}
p{margin:0 0 .8em}
a{color:var(--brand-dark)}
img{max-width:100%;display:block}
button,input,select,textarea{font:inherit;color:inherit}
:focus-visible{outline:3px solid var(--focus);outline-offset:2px}
[hidden]{display:none!important}
.muted{color:var(--muted)} .small{font-size:14px} .xs{font-size:13px} .center{text-align:center}
.icon{width:20px;height:20px;flex:none;stroke:currentColor;fill:none;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}

/* 按鈕 */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;padding:0 20px;border-radius:12px;border:1px solid transparent;font-weight:600;font-size:16px;line-height:1.2;cursor:pointer;text-decoration:none;background:var(--surface-2);color:var(--text);transition:background .15s,border-color .15s}
.btn-primary{background:var(--brand);color:#fff}
.btn-primary:hover{background:var(--brand-dark)}
.btn-outline{background:var(--surface);border-color:var(--line-strong);color:var(--brand-dark)}
.btn-outline:hover{background:var(--brand-soft);border-color:var(--brand-mid)}
.btn-lg{min-height:54px;font-size:18px;padding:0 28px}
.btn-block{display:flex;width:100%}
.btn[disabled]{opacity:.6;cursor:wait}
.btn-row{display:grid;grid-template-columns:1fr 1fr;gap:10px}

/* 頂欄 */
.top{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 16px;border-bottom:1px solid var(--line);background:var(--surface)}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);font-weight:800;font-size:17px;letter-spacing:.06em}
.brand img{width:32px;height:32px;border-radius:6px}
.top-link{font-weight:600;font-size:15px;text-decoration:none}

/* 徽標 / 卡片 / 頭像 */
.badge{display:inline-flex;align-items:center;gap:5px;padding:2px 10px;border-radius:99px;font-size:12.5px;font-weight:600;line-height:1.6;background:var(--surface-2);color:var(--muted);white-space:nowrap}
.badge-brand{background:var(--brand-soft);color:var(--brand-dark)}
.badge-ok{background:var(--ok-soft);color:var(--ok)}
.badge-ok::before{content:"";width:6px;height:6px;border-radius:50%;background:currentColor}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}
.avatar{width:44px;height:44px;border-radius:50%;flex:none;display:grid;place-items:center;overflow:hidden;font-weight:700;font-size:18px;color:#fff;background:linear-gradient(135deg,#17606b,#3f8f8a)}
.avatar.a2{background:linear-gradient(135deg,#a8630f,#d49a3d)}
.avatar.lg{width:68px;height:68px;font-size:26px}
.avatar img{width:100%;height:100%;object-fit:cover}

/* 手機：單欄 H5 */
.hero-poster{padding:16px 16px 0}
.poster{display:block;max-width:440px;margin:0 auto;border-radius:12px;overflow:hidden;box-shadow:0 10px 30px rgba(35,48,47,.18);cursor:zoom-in}
.poster img{width:100%;height:auto}
.hero-text{padding:18px 16px 4px}
.hero-tags{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:10px}
.event-title{font-size:26px;font-weight:800;margin:0 0 4px;letter-spacing:.02em}
.event-sub{color:var(--muted);font-size:16px;margin:0}
.section{padding:20px 16px}
.section+.section,.col-main>.section:first-child{border-top:8px solid var(--surface-2)}
.section>h2{display:flex;align-items:center;gap:8px;font-size:18px}
.section>h2::before{content:"";width:4px;height:18px;border-radius:2px;background:var(--brand)}
.info-list{list-style:none;padding:0;margin:0}
.info-list li{display:flex;gap:12px;padding:11px 0;border-bottom:1px solid var(--line)}
.info-list li:last-child{border-bottom:0}
.info-ic{width:38px;height:38px;border-radius:10px;background:var(--brand-soft);color:var(--brand-dark);display:grid;place-items:center;flex:none}
.info-list b{display:block;font-size:15.5px}
.info-list span{font-size:14.5px;color:var(--muted)}
.prose p{margin-bottom:.9em}
.prose h3{font-size:16px;margin:1.2em 0 .4em}
.prose ul{padding-left:1.3em;margin:0}
.prose li{margin:.25em 0}
.speaker{display:flex;gap:14px;padding:14px 0;border-bottom:1px solid var(--line)}
.speaker:last-child{border-bottom:0}
.speaker h3{font-size:17px;margin:4px 0 2px}
.speaker h3 small{margin-left:8px;font-size:13px;font-weight:600;color:var(--muted)}
.speaker .role{font-size:14px;color:var(--brand-dark);font-weight:600;margin-bottom:4px}
.speaker p{font-size:15px;color:var(--muted);margin:0}
.map{display:block;width:100%;height:200px;border:1px solid var(--line);border-radius:12px;margin:4px 0 10px;background:var(--surface-2)}
.host-row{display:flex;gap:12px;align-items:center}
.host-row img{width:48px;height:48px;border-radius:10px;flex:none}
.host-row b{display:block;line-height:1.35}
.side-link{display:inline-block;font-weight:600;font-size:14.5px}
.d-only{display:none}
.site-foot{border-top:1px solid var(--line);padding:22px 16px 30px;text-align:center;color:var(--muted);font-size:13.5px}
.has-cta{padding-bottom:84px}
.cta-bar{position:fixed;left:0;right:0;bottom:0;z-index:50;background:rgba(255,255,255,.97);border-top:1px solid var(--line);padding:10px 16px calc(10px + env(safe-area-inset-bottom));box-shadow:0 -6px 18px rgba(35,48,47,.08)}
.cta-inner{max-width:560px;margin:0 auto;display:flex;align-items:center;gap:12px}
.cta-info{font-size:13px;color:var(--muted);line-height:1.4;min-width:0}
.cta-info b{display:block;color:var(--text);font-size:15px}
.cta-inner .btn{flex:1}
.toast{position:fixed;left:50%;bottom:96px;transform:translateX(-50%);z-index:500;background:#23302f;color:#fff;padding:11px 20px;border-radius:12px;font-size:15px;max-width:calc(100vw - 32px);box-shadow:0 8px 24px rgba(0,0,0,.25)}

/* 表單 */
.field{margin-bottom:18px}
.field>label,.label{display:block;font-weight:600;margin-bottom:6px;font-size:15px}
.req{color:var(--danger);margin-left:2px}
.opt{color:var(--muted);font-weight:400;font-size:13px;margin-left:6px}
.input,.textarea{display:block;width:100%;min-height:48px;padding:10px 12px;border:1px solid var(--line-strong);border-radius:10px;background:#fff;font-size:16px}
.textarea{min-height:96px;resize:vertical}
.input:focus,.textarea:focus{outline:none;border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-mid)}
.hint{font-size:13px;color:var(--muted);margin-top:5px}
.error-msg{display:none;color:var(--danger);font-size:13.5px;margin-top:5px;font-weight:600}
.field.has-error .input{border-color:var(--danger);background:#fffafa}
.field.has-error .error-msg{display:block}
.choices{display:grid;gap:8px}
.choice{display:flex;gap:10px;align-items:center;min-height:48px;padding:10px 12px;border:1px solid var(--line-strong);border-radius:10px;background:#fff;cursor:pointer;font-weight:500}
.choice input{width:20px;height:20px;accent-color:var(--brand);flex:none}
.choice:has(input:checked){border-color:var(--brand);background:var(--brand-soft)}
.stepper{display:inline-flex;border:1px solid var(--line-strong);border-radius:12px;overflow:hidden;background:#fff}
.stepper button{width:52px;min-height:50px;border:0;background:var(--surface-2);font-size:22px;font-weight:600;cursor:pointer;color:var(--brand-dark)}
.stepper button:hover{background:var(--brand-soft)}
.stepper input{width:64px;border:0;text-align:center;font-size:20px;font-weight:700;background:#fff;-moz-appearance:textfield}
.stepper input::-webkit-outer-spin-button,.stepper input::-webkit-inner-spin-button{-webkit-appearance:none;margin:0}
.form-alert{display:none;margin-bottom:16px;padding:12px 14px;border-radius:12px;background:#fbe4e1;color:#8f2a21;font-size:14.5px}
.form-alert.on{display:block}
.hp{position:absolute;left:-9999px;width:1px;height:1px;opacity:0}

/* 報名成功 */
.ticket{background:var(--surface);border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);overflow:hidden}
.ticket-top{background:linear-gradient(160deg,#0f4a53,#17606b);color:#fff;padding:22px 20px;text-align:center}
.ticket-top .check{width:52px;height:52px;border-radius:50%;background:rgba(255,255,255,.18);display:grid;place-items:center;margin:0 auto 10px}
.ticket-top h1{color:#fff;font-size:23px;margin:0 0 4px}
.ticket-body{padding:6px 20px 14px}

/* ---------- 電腦：全屏寬版 ---------- */
@media (min-width:900px){
  .wrap{max-width:1200px;margin:0 auto;padding:0 32px}
  .top{padding:14px max(32px,calc((100% - 1136px)/2))}
  .brand{font-size:19px}
  .brand img{width:38px;height:38px}
  .d-only{display:block}
  .m-only{display:none!important}
  .has-cta{padding-bottom:0}
  .cta-bar{display:none}
  .hero-band{padding:44px 0 52px;background:radial-gradient(circle at 8% 0,rgba(255,255,255,.75) 0,rgba(255,255,255,0) 46%),linear-gradient(180deg,var(--brand-soft) 0%,var(--bg) 100%);border-bottom:1px solid var(--line)}
  .hero-grid{display:grid;grid-template-columns:400px minmax(0,1fr);gap:56px;align-items:start}
  .hero-poster{padding:0}
  .poster{margin:0;max-width:400px;box-shadow:0 18px 44px rgba(35,48,47,.22)}
  .hero-main{display:flex;flex-direction:column;gap:22px;min-width:0;padding-top:6px;position:sticky;top:24px}
  .hero-text{padding:0}
  .hero-tags{margin-bottom:14px}
  .hero-tags .badge{font-size:13.5px;padding:3px 12px}
  .event-title{font-size:clamp(34px,3.6vw,44px);line-height:1.2;margin-bottom:10px}
  .event-sub{font-size:19px}
  .hero-info{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:4px 22px}
  .hero-info .info-list li{padding:15px 0;gap:14px}
  .hero-info .info-ic{width:42px;height:42px}
  .hero-info .info-list b{font-size:16.5px}
  .hero-info .info-list span{font-size:15px}
  .hero-cta{display:flex;gap:14px;flex-wrap:wrap}
  .hero-cta .btn{min-height:58px;padding:0 40px;font-size:19px}
  .hero-cta .btn-outline{font-size:17px;padding:0 26px}
  .hero-info+.section{border-top:0}
  .page-cols{display:grid;grid-template-columns:minmax(0,2fr) minmax(0,1fr);gap:32px;align-items:start;padding:36px 0 64px}
  .col-main,.col-side{display:flex;flex-direction:column;gap:22px;min-width:0}
  .col-side{position:sticky;top:20px}
  .page-cols .section{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:26px 30px;border-top:1px solid var(--line)}
  .col-side .section{padding:20px}
  .col-main .section>h2{font-size:21px;margin-bottom:16px}
  .col-main .section>h2::before{height:21px}
  .col-side .section>h2{font-size:17px;margin-bottom:12px}
  .col-side .section>h2::before{height:17px}
  .col-main .prose{font-size:16.5px;line-height:1.85}
  .map{height:180px}
  .toast{bottom:40px}
  /* 報名頁 */
  .reg-grid{display:grid;grid-template-columns:340px minmax(0,1fr);gap:40px;align-items:start;padding:36px 0 64px}
  .reg-aside{position:sticky;top:20px}
  .reg-aside .poster{max-width:none;margin-bottom:16px}
  .reg-aside .section{padding:0}
  .reg-main.section{padding:0}
  .reg-main{max-width:620px}
}