/* ============================================================
   AI阿智实战教程 · 课程网站 —— 样式
   深色科技 + 品牌橙 #FF5A00
   ============================================================ */
:root{
  --bg:#070811;
  --bg2:#0a0c18;
  --surface:#0f1220;
  --card:#131626;
  --line:rgba(255,255,255,.08);
  --line-strong:rgba(255,255,255,.14);
  --ink:#F4F6FA;
  --ink2:#AFB6C9;
  --ink3:#6E7690;
  --accent:#FF5A00;
  --accent-2:#FF8A3C;
  --accent-soft:rgba(255,90,0,.12);
  --ok:#34D17B;
  --radius:18px;
  --font:'Microsoft YaHei',system-ui,-apple-system,'PingFang SC',sans-serif;
  --mono:ui-monospace,'SF Mono','Cascadia Mono',Consolas,monospace;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--ink);font-family:var(--font);line-height:1.6;-webkit-font-smoothing:antialiased}
::selection{background:var(--accent);color:#fff}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer;border:none}
img{display:block;max-width:100%}

.container{width:min(1180px,92vw);margin:0 auto}
.section{padding:92px 0;position:relative}
.mono{font-family:var(--mono);letter-spacing:.04em}

/* 背景星点 + 橙色辉光 */
.bg-veil{position:fixed;inset:0;z-index:-1;background:
  radial-gradient(1000px 520px at 78% -8%,var(--accent-soft),transparent 62%),
  radial-gradient(700px 460px at 8% 26%,rgba(58,74,138,.18),transparent 60%),
  linear-gradient(180deg,var(--bg) 0%,var(--bg2) 100%);}

/* 按钮 */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;font-weight:700;border-radius:12px;transition:.22s;font-size:16px}
.btn .ar{transition:transform .22s}
.btn:hover .ar{transform:translateX(3px)}
.btn-primary{background:linear-gradient(180deg,var(--accent-2),var(--accent));color:#fff;box-shadow:0 10px 28px -8px rgba(255,90,0,.55)}
.btn-primary:hover{filter:brightness(1.06);box-shadow:0 14px 34px -8px rgba(255,90,0,.7)}
.btn-ghost{color:var(--ink);border:1px solid var(--line-strong);background:rgba(255,255,255,.02)}
.btn-ghost:hover{border-color:var(--accent);color:#fff}
.btn-lg{padding:16px 30px;font-size:17px}
.btn-md{padding:12px 22px;font-size:15px}

/* 段落标题系统 */
.kicker{display:flex;align-items:center;gap:10px;font-family:var(--mono);font-size:13px;color:var(--accent);letter-spacing:.1em;margin-bottom:18px;font-weight:600}
.kicker::before{content:'';width:26px;height:3px;background:var(--accent);border-radius:2px}
.h2{font-size:clamp(28px,4vw,42px);font-weight:800;letter-spacing:-.01em;line-height:1.18}
.h2 em{font-style:normal;color:var(--accent)}
.sub{color:var(--ink2);font-size:17px;max-width:56ch;margin-top:16px}

/* ============================================================
   顶部导航
   ============================================================ */
.nav{position:sticky;top:0;z-index:50;backdrop-filter:blur(14px);background:rgba(7,8,17,.72);border-bottom:1px solid var(--line)}
.nav-in{height:64px;display:flex;align-items:center;justify-content:space-between}
.brand{display:flex;align-items:center;gap:12px;font-weight:800;font-size:16px}
.brand .logo{display:inline-flex;align-items:center;background:var(--accent);color:#fff;font-weight:900;border-radius:9px;padding:3px 8px;font-size:14px}
.brand .sub-logo{color:var(--ink3);font-weight:600;font-size:14px}
.nav-links{display:flex;gap:30px;color:var(--ink2);font-size:15px}
.nav-links a:hover{color:#fff}
.nav-cta{padding:10px 20px;font-size:14px}
@media(max-width:760px){.nav-links{display:none}}

/* ============================================================
   首页 Hero
   ============================================================ */
.hero{padding:74px 0 86px;overflow:hidden}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:56px;align-items:center}
.hero .badge{display:inline-flex;align-items:center;gap:8px;font-size:13px;color:var(--ink2);border:1px solid var(--line-strong);padding:7px 14px;border-radius:999px;background:rgba(255,255,255,.02);font-weight:600}
.hero .badge i{width:7px;height:7px;border-radius:50%;background:var(--accent);display:inline-block}
.hero h1{font-size:clamp(34px,5vw,58px);font-weight:900;line-height:1.12;letter-spacing:-.015em;margin:22px 0 20px}
.hero h1 .grad{background:linear-gradient(90deg,#fff 0%,#ffd9b8 55%,var(--accent-2) 100%);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero h1 .o{color:var(--accent)}
.hero .lead{color:var(--ink2);font-size:18px;max-width:50ch}
.hero .lead b{color:var(--ink)}
.hero-cta{display:flex;gap:16px;margin-top:34px;flex-wrap:wrap}
.hero .trust{display:flex;flex-wrap:wrap;gap:22px;margin-top:34px;color:var(--ink2);font-size:14px}
.hero .trust span{display:flex;align-items:center;gap:8px;font-weight:600}
.hero .trust .dot{color:var(--accent)}
.hero-visual{position:relative}
.visual-card{background:var(--card);border:1px solid var(--line);border-radius:22px;padding:14px;box-shadow:0 30px 70px -30px rgba(0,0,0,.7);overflow:hidden}
.visual-card .screen{position:relative;border-radius:14px;overflow:hidden}
.visual-card img.cover{width:100%;aspect-ratio:7/4;object-fit:cover}
.visual-card .play{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:rgba(7,8,17,.34)}
.visual-card .play .pc{width:64px;height:64px;border-radius:50%;background:var(--accent);display:flex;align-items:center;justify-content:center;color:#fff;font-size:22px;box-shadow:0 0 0 10px rgba(255,90,0,.18),0 16px 40px -8px rgba(255,90,0,.6)}
.visual-card .cap{display:flex;justify-content:space-between;align-items:center;padding:12px 6px 4px;font-size:13px;color:var(--ink3)}
.visual-card .cap .b{color:var(--ink);font-weight:700}
.hero-float{position:absolute;left:-18px;bottom:-16px;background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:14px 16px;box-shadow:0 20px 46px -20px rgba(0,0,0,.6);display:flex;align-items:center;gap:12px}
.hero-float .num{font-family:var(--mono);font-size:22px;font-weight:800;color:var(--accent)}
.hero-float small{display:block;color:var(--ink3);font-size:12px}
@media(max-width:900px){.hero-grid{grid-template-columns:1fr;gap:40px}.hero-float{left:0}}

/* ============================================================
   数据证明条
   ============================================================ */
.proof{border-block:1px solid var(--line);background:rgba(255,255,255,.015)}
.proof-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;padding:34px 0}
.proof .p{border-left:2px solid var(--line-strong);padding-left:18px}
.proof .p b{font-size:28px;font-weight:800;display:block;letter-spacing:-.01em}
.proof .p b em{font-style:normal;color:var(--accent)}
.proof .p small{color:var(--ink3);font-size:13px}
@media(max-width:760px){.proof-grid{grid-template-columns:1fr 1fr}}

/* ============================================================
   免费试听
   ============================================================ */
.trial-wrap{display:grid;grid-template-columns:1.1fr .9fr;gap:40px;align-items:center;margin-top:44px}
.trial-player{position:relative;border-radius:20px;overflow:hidden;border:1px solid var(--line);background:#000;box-shadow:0 30px 70px -30px rgba(0,0,0,.7);aspect-ratio:16/9}
.trial-player video{width:100%;height:100%;display:block;background:#000}
.trial-side .trial-tag{display:inline-flex;align-items:center;gap:8px;font-size:13px;color:var(--accent);border:1px solid rgba(255,90,0,.35);background:var(--accent-soft);padding:6px 13px;border-radius:999px;font-weight:700;margin-bottom:18px}
.trial-side h3{font-size:26px;font-weight:800;margin-bottom:12px}
.trial-side p{color:var(--ink2);font-size:15.5px;line-height:1.85;margin-bottom:26px}
@media(max-width:820px){.trial-wrap{grid-template-columns:1fr;gap:26px}}

/* ============================================================
   五大板块
   ============================================================ */
.mod-wrap{display:grid;grid-template-columns:1fr 1fr;gap:22px;margin-top:44px}
.mod{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:30px 30px 26px;transition:.25s;position:relative;overflow:hidden}
.mod::after{content:'';position:absolute;top:0;left:0;right:0;height:2px;background:linear-gradient(90deg,var(--accent),transparent);opacity:0;transition:.25s}
.mod:hover{transform:translateY(-4px);border-color:var(--line-strong)}
.mod:hover::after{opacity:1}
.mod .head{display:flex;align-items:baseline;gap:14px;margin-bottom:6px}
.mod .no{font-family:var(--mono);font-size:14px;color:var(--accent);font-weight:700}
.mod h3{font-size:20px;font-weight:800}
.mod p{color:var(--ink3);font-size:14px;margin:4px 0 18px}
.mod ul{list-style:none}
.mod li{display:flex;gap:10px;align-items:baseline;color:var(--ink2);font-size:15px;padding:7px 0;border-top:1px dashed rgba(255,255,255,.06)}
.mod li::before{content:'›';color:var(--accent);font-weight:800}
@media(max-width:820px){.mod-wrap{grid-template-columns:1fr}}

/* 四个核心岗位 */
.roles{margin-top:38px;background:linear-gradient(180deg,rgba(255,90,0,.07),rgba(255,90,0,.02));border:1px solid rgba(255,90,0,.22);border-radius:var(--radius);padding:30px}
.roles-title{font-family:var(--mono);font-size:13px;color:var(--accent);letter-spacing:.1em;font-weight:700;margin-bottom:20px}
.role-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.role{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:20px;position:relative;overflow:hidden}
.role .ri{font-family:var(--mono);font-size:12px;color:var(--accent);font-weight:800}
.role b{display:block;font-size:17px;font-weight:800;margin:8px 0 6px}
.role small{color:var(--ink3);font-size:12.5px}
@media(max-width:900px){.role-grid{grid-template-columns:1fr 1fr}}
@media(max-width:600px){.role-grid{grid-template-columns:1fr}}
.mod-note{margin-top:24px;text-align:center;color:var(--ink2);font-size:14px}
.mod-note b{color:var(--accent);font-size:16px}

/* ============================================================
   三步 How it works
   ============================================================ */
.how{background:var(--bg2)}
.how-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin-top:44px;counter-reset:step}
.step{position:relative;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:34px 28px}
.step .sn{font-family:var(--mono);font-size:15px;color:var(--accent);font-weight:800}
.step h4{font-size:19px;font-weight:800;margin:16px 0 8px}
.step p{color:var(--ink3);font-size:14.5px}
.step .idx{position:absolute;top:22px;right:26px;font-family:var(--mono);font-size:44px;font-weight:800;color:rgba(255,255,255,.04)}
@media(max-width:820px){.how-grid{grid-template-columns:1fr}}

/* ============================================================
   课程学习
   ============================================================ */
.study-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;margin-top:44px}
.study-item{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:30px 26px;transition:.25s;position:relative;overflow:hidden}
.study-item::after{content:'';position:absolute;top:0;left:0;right:0;height:2px;background:linear-gradient(90deg,var(--accent),transparent);opacity:0;transition:.25s}
.study-item:hover{transform:translateY(-4px);border-color:var(--line-strong)}
.study-item:hover::after{opacity:1}
.study-item .si-ico{font-size:26px;margin-bottom:16px}
.study-item h4{font-size:18px;font-weight:800;margin-bottom:8px}
.study-item p{color:var(--ink3);font-size:14px}
@media(max-width:900px){.study-grid{grid-template-columns:1fr 1fr}}
@media(max-width:600px){.study-grid{grid-template-columns:1fr}}

/* ============================================================
   价格
   ============================================================ */
.pricing{position:relative}
.price-card{max-width:520px;margin:0 auto;background:linear-gradient(180deg,var(--card),var(--surface));border:1px solid var(--line-strong);border-radius:26px;padding:40px;text-align:center;position:relative;overflow:hidden}
.price-card::before{content:'';position:absolute;top:-90px;left:50%;transform:translateX(-50%);width:340px;height:180px;background:radial-gradient(closest-side,var(--accent-soft),transparent);z-index:0}
.price-tag{position:relative;z-index:1}
.price-tag .now{font-size:60px;font-weight:900;letter-spacing:-.02em}
.price-tag .now small{font-size:26px;font-weight:700;margin-right:4px}
.price-tag .was{display:inline-block;color:var(--ink3);text-decoration:line-through;margin-left:14px;font-size:18px}
.price-note{color:var(--ink2);font-size:14.5px;margin-top:6px;position:relative;z-index:1}
.price-list{list-style:none;margin:28px 0 30px;text-align:left;position:relative;z-index:1}
.price-list li{display:flex;gap:12px;align-items:flex-start;padding:9px 0;color:var(--ink2);font-size:15px}
.price-list li::before{content:'✓';color:var(--ok);font-weight:800;flex-shrink:0}
.price-card .btn{width:100%}
.src-box{margin-top:18px;font-size:13px;color:var(--ink3);position:relative;z-index:1}
.src-box b{color:var(--ink2)}

/* ============================================================
   FAQ
   ============================================================ */
.faq{max-width:760px;margin:44px auto 0}
.faq-item{border:1px solid var(--line);border-radius:14px;margin-bottom:14px;overflow:hidden;background:var(--surface)}
.faq-item summary{cursor:pointer;padding:20px 24px;font-weight:700;font-size:16px;list-style:none;display:flex;justify-content:space-between;align-items:center}
.faq-item summary::after{content:'+';font-size:22px;color:var(--accent);font-weight:400;transition:.2s}
.faq-item[open] summary::after{transform:rotate(45deg)}
.faq-item .fa-b{padding:0 24px 20px;color:var(--ink2);font-size:15px}

/* ============================================================
   提示词库
   ============================================================ */
.prompts{background:var(--bg2)}
.prompt-card{max-width:820px;margin:44px auto 0;display:flex;align-items:center;justify-content:space-between;gap:20px;flex-wrap:wrap;background:var(--card);border:1px solid var(--line-strong);border-radius:20px;padding:28px 32px}
.prompt-info{display:flex;align-items:center;gap:18px}
.prompt-info .p-ico{width:58px;height:58px;border-radius:14px;background:var(--accent-soft);display:flex;align-items:center;justify-content:center;font-size:26px;flex-shrink:0}
.prompt-info h3{font-size:19px;font-weight:800}
.prompt-info p{color:var(--ink3);font-size:13.5px;margin-top:4px}
.prompt-tip{text-align:center;color:var(--ink3);font-size:13px;margin-top:16px}
@media(max-width:640px){.prompt-card{flex-direction:column;align-items:flex-start}.prompt-card .btn{width:100%}}

/* ============================================================
   最终 CTA + Footer
   ============================================================ */
.final{border-block:1px solid var(--line);background:var(--bg2)}
.final-in{text-align:center;padding:70px 0}
.final-in h2{font-size:clamp(28px,4vw,42px);font-weight:800}
.final-in p{color:var(--ink2);max-width:54ch;margin:16px auto 30px}
footer{border-top:1px solid var(--line);padding:34px 0;color:var(--ink3);font-size:13.5px}
footer .ctr{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}

/* ============================================================
   学习页 learn
   ============================================================ */
.learn-top{padding:40px 0 0}
.learn-top .crumb{font-family:var(--mono);font-size:13px;color:var(--ink3);margin-bottom:14px}
.learn-top h1{font-size:clamp(24px,3vw,34px);font-weight:800}
.learn-top .status{margin-top:14px;display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.chip{font-size:13px;padding:6px 13px;border-radius:999px;border:1px solid var(--line-strong);color:var(--ink2);display:inline-flex;gap:7px;align-items:center}
.chip.unlocked{color:var(--ok);border-color:rgba(52,209,123,.35)}
.learn-layout{display:grid;grid-template-columns:360px 1fr;gap:28px;padding:34px 0 80px}
@media(max-width:860px){.learn-layout{grid-template-columns:1fr}}

/* 章节列表 */
.chapters{display:flex;flex-direction:column;gap:10px;position:sticky;top:82px;align-self:start;max-height:calc(100vh - 110px);overflow:auto}
.ch{border:1px solid var(--line);border-radius:14px;background:var(--surface);overflow:hidden}
.ch .ch-head{padding:14px 16px;display:flex;align-items:center;justify-content:space-between;gap:10px;cursor:pointer}
.ch .ch-head .t{font-weight:700;font-size:15px;display:flex;gap:10px;align-items:center}
.ch .ch-head .t .no{font-family:var(--mono);color:var(--accent);font-size:13px}
.ch .ch-head .cnt{font-family:var(--mono);font-size:12px;color:var(--ink3)}
.ch.avail .ch-head{border-left:3px solid var(--accent)}
.ch .ch-lessons{padding:4px 8px 8px}
.ch:not(.open) .ch-lessons{display:none}
.lesson{display:flex;align-items:center;gap:12px;padding:8px 10px;border-radius:10px;font-size:14px;color:var(--ink2);cursor:pointer;transition:.15s}
.lesson:hover{background:rgba(255,255,255,.04)}
.lesson .st{width:18px;height:18px;border-radius:5px;border:1.5px solid var(--line-strong);display:flex;align-items:center;justify-content:center;font-size:10px;flex-shrink:0}
.lesson.opened .st{border-color:var(--accent);color:var(--accent)}
.lesson.active{background:var(--accent-soft);color:#fff}
.lesson.locked{opacity:.5;cursor:not-allowed}
.lesson .lt{flex:1}
.lesson .lock-ic{color:var(--ink3);font-size:12px}

/* 播放区 */
.player-card{background:var(--card);border:1px solid var(--line);border-radius:20px;padding:30px;min-height:420px;position:relative;overflow:hidden;display:flex;flex-direction:column}
.player-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:22px}
.player-top .path{font-family:var(--mono);font-size:13px;color:var(--ink3)}
.player-top .path b{color:var(--accent)}
.video-box{position:relative;border-radius:14px;overflow:hidden;background:#000;border:1px solid var(--line);aspect-ratio:16/9}
.video-box video{width:100%;height:100%;display:block;background:#000}
/* 禁止下载/保存 */
video::-webkit-media-controls-download-button{display:none!important}
/* 播放水印 */
.wm{position:absolute;inset:0;pointer-events:none;overflow:hidden;z-index:2;display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:repeat(3,1fr);opacity:.34}
.wm-item{display:flex;align-items:center;justify-content:center;color:#fff;font-size:12px;font-family:var(--mono);text-shadow:0 1px 3px rgba(0,0,0,.65);transform:rotate(-16deg);white-space:nowrap;letter-spacing:.02em}
.video-empty{position:absolute;inset:0;z-index:3;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:16px;background:radial-gradient(circle at 50% 40%,var(--accent-soft),transparent 70%),#0b0d17;color:var(--ink3);cursor:pointer}
.video-empty i{width:70px;height:70px;border-radius:50%;background:var(--accent);color:#fff;font-style:normal;font-size:24px;display:flex;align-items:center;justify-content:center;box-shadow:0 0 0 10px rgba(255,90,0,.16),0 18px 44px -10px rgba(255,90,0,.6);transition:.2s}
.video-empty:hover i{transform:scale(1.06)}
.video-empty p{font-size:15px}
.player-mid{text-align:center;flex:1;padding-top:24px}
.player-mid h2{font-size:22px;font-weight:800}
.player-mid .seg{font-family:var(--mono);font-size:13px;color:var(--ink3);margin-top:8px}
.player-bar{margin-top:22px;text-align:center}
.prog{height:6px;border-radius:3px;background:rgba(255,255,255,.1);position:relative;cursor:pointer}
.prog .fill{position:absolute;inset:0 auto 0 0;width:0;background:var(--accent);border-radius:3px}
.player-ctrls{display:flex;align-items:center;justify-content:center;gap:26px;margin-top:22px}
.ctrl{width:52px;height:52px;border-radius:50%;background:var(--surface);border:1px solid var(--line-strong);color:#fff;display:flex;align-items:center;justify-content:center;font-size:18px;transition:.18s}
.ctrl:hover{border-color:var(--accent);color:var(--accent)}
.ctrl.main{width:66px;height:66px;background:var(--accent);border:none;font-size:24px;box-shadow:0 12px 30px -10px rgba(255,90,0,.6)}
.ctrl.main:hover{filter:brightness(1.08)}
.player-time{font-family:var(--mono);font-size:12.5px;color:var(--ink3);display:flex;justify-content:space-between;margin-bottom:6px}

/* 解锁弹层 */
.mask{position:fixed;inset:0;background:rgba(4,5,10,.72);backdrop-filter:blur(6px);z-index:100;display:none;align-items:center;justify-content:center;padding:20px}
.mask.show{display:flex}
.lock-modal{background:#10131f;border:1px solid var(--line-strong);border-radius:22px;padding:40px;max-width:460px;width:100%;text-align:center;box-shadow:0 40px 90px -30px rgba(0,0,0,.8)}
.lock-modal .lock-ico{width:64px;height:64px;border-radius:50%;background:var(--accent-soft);color:var(--accent);display:flex;align-items:center;justify-content:center;font-size:26px;margin:0 auto 20px}
.lock-modal h3{font-size:22px;font-weight:800}
.lock-modal p{color:var(--ink2);font-size:15px;margin:12px 0 26px}
.lock-input{display:flex;gap:10px;margin-bottom:16px}
.lock-input input{flex:1;background:var(--surface);border:1px solid var(--line-strong);border-radius:10px;padding:13px 14px;color:#fff;font-family:var(--mono);font-size:15px}
.lock-input input:focus{outline:none;border-color:var(--accent)}
.lock-tip{font-size:12.5px;color:var(--ink3);margin-top:10px}
.toast{position:fixed;bottom:30px;left:50%;transform:translateX(-50%);background:var(--accent);color:#fff;padding:12px 22px;border-radius:12px;font-weight:700;font-size:14px;opacity:0;transition:.3s;z-index:120;pointer-events:none}
.toast.show{opacity:1;transform:translateX(-50%) translateY(-6px)}

@media(max-width:860px){.chapters{position:static;max-height:none}}