/* =========================================================
   Landing page khóa học online — style.css
   Phong cách: chuyển đổi (conversion). Xanh dương đậm + vàng nút CTA,
   chữ to rõ, nhiều bằng chứng xã hội, CTA lặp lại.
   Bố cục khác các mẫu trước:
     - MỘT TRANG DÀI, không có trang con. Menu neo cuộn tới section
     - Header tối giản: logo + 1 nút CTA + thanh tiến độ đọc
     - Hero: chữ trái, ảnh + thẻ nổi phải, hàng logo tin cậy ngay dưới
     - Vấn đề (3 nỗi đau) → Giải pháp (lộ trình có số) → Học viên nói (slider)
       → Nội dung khóa (accordion) → Giảng viên → Giá 2 gói → FAQ → CTA cuối
     - Thanh CTA DÍNH ĐÁY khi cuộn qua hero, có đếm ngược
   Ảnh: mỗi khối ảnh dùng biến --img trên thẻ HTML (link trực tiếp Wikimedia/Flickr, xem CREDITS.md).
   ========================================================= */

:root{
  --navy:#0B2545;
  --navy-2:#13315C;
  --blue:#1E63E9;
  --blue-soft:#E8F0FE;
  --gold:#FFB703;
  --gold-deep:#E5A100;
  --bg:#FFFFFF;
  --bg-2:#F6F8FB;
  --line:#E3E8EF;
  --text:#1F2937;
  --muted:#5B6B7F;
  --green:#16A34A;
  --red:#DC2626;
  --radius:14px;
  --radius-lg:24px;
  --shadow:0 1px 2px rgba(11,37,69,.05), 0 10px 30px rgba(11,37,69,.08);
  --shadow-lg:0 24px 60px rgba(11,37,69,.18);
  --ph:linear-gradient(135deg,#E8F0FE 0%,#D2E0FB 55%,#BBD0F8 100%);
}

*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:80px}
body{font-family:'Be Vietnam Pro',system-ui,-apple-system,sans-serif;color:var(--text);background:var(--bg);font-size:16px;line-height:1.7;-webkit-font-smoothing:antialiased;padding-bottom:0}
a{color:inherit;text-decoration:none}
button{font:inherit;cursor:pointer;border:none;background:none;color:inherit}
img{max-width:100%;display:block}
svg{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:2.2;stroke-linecap:round;stroke-linejoin:round;flex:none}
.ph{background:var(--img,var(--ph)) center/cover no-repeat,var(--ph)}
.container{width:min(1140px,100% - 40px);margin-inline:auto}
h1,h2,h3,h4{font-weight:800;line-height:1.2;letter-spacing:-.02em;color:var(--navy)}
b,strong{font-weight:700}

/* ---------- Nút ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;padding:16px 30px;border-radius:999px;font-weight:800;font-size:16px;transition:.2s;white-space:nowrap}
.btn svg{width:18px;height:18px}
.btn--gold{background:var(--gold);color:var(--navy);box-shadow:0 10px 24px rgba(255,183,3,.35)}
.btn--gold:hover{background:var(--gold-deep);transform:translateY(-2px)}
.btn--navy{background:var(--navy);color:#fff}
.btn--navy:hover{background:var(--navy-2)}
.btn--line{border:2px solid var(--line);color:var(--navy);background:#fff}
.btn--line:hover{border-color:var(--navy)}
.btn--lg{padding:20px 40px;font-size:18px}
.btn--sm{padding:11px 20px;font-size:14px}

/* ---------- Header + thanh tiến độ ---------- */
.header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.94);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.header__in{display:flex;align-items:center;justify-content:space-between;gap:20px;min-height:70px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;color:var(--navy);font-size:19px}
.logo__mark{width:38px;height:38px;border-radius:10px;background:var(--blue);color:#fff;display:grid;place-items:center;font-size:16px}
.anchors{display:flex;gap:4px}
.anchors a{padding:8px 14px;border-radius:999px;font-size:14px;font-weight:600;color:var(--muted)}
.anchors a:hover{background:var(--blue-soft);color:var(--blue)}
.progress{position:absolute;left:0;bottom:-1px;height:3px;background:var(--gold);width:0;transition:width .1s}

/* ---------- Hero ---------- */
.hero{padding:70px 0 40px;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;right:-10%;top:-20%;width:600px;height:600px;border-radius:50%;background:radial-gradient(closest-side,var(--blue-soft),transparent);pointer-events:none}
.hero__in{display:grid;grid-template-columns:1.1fr .9fr;gap:60px;align-items:center;position:relative}
.eyebrow{display:inline-flex;align-items:center;gap:8px;padding:7px 14px;border-radius:999px;background:var(--blue-soft);color:var(--blue);font-size:13px;font-weight:700}
.eyebrow b{background:var(--blue);color:#fff;padding:2px 8px;border-radius:999px;font-size:11.5px}
.hero h1{font-size:clamp(34px,4.8vw,56px);margin:20px 0 18px}
.hero h1 mark{background:linear-gradient(transparent 55%,var(--gold) 55%);color:inherit;padding:0 4px}
.hero p{font-size:18px;color:var(--muted);max-width:540px}
.hero__cta{display:flex;flex-wrap:wrap;gap:12px;margin-top:30px;align-items:center}
.hero__cta small{display:block;color:var(--muted);font-size:13px;width:100%}
.hero__proof{display:flex;align-items:center;gap:14px;margin-top:28px}
.faces{display:flex}
.faces .ph{width:40px;height:40px;border-radius:50%;border:3px solid #fff;margin-left:-12px;box-shadow:var(--shadow)}
.faces .ph:first-child{margin-left:0}
.hero__proof b{color:var(--navy)}
.hero__proof small{display:block;color:var(--muted);font-size:13px}
.stars{color:var(--gold);letter-spacing:1px}

.hero__art{position:relative}
.hero__art .ph{aspect-ratio:5/6;border-radius:var(--radius-lg);box-shadow:var(--shadow-lg)}
.float{position:absolute;background:#fff;border-radius:var(--radius);padding:14px 18px;box-shadow:var(--shadow-lg);display:flex;gap:12px;align-items:center;font-size:13.5px}
.float .ic{width:40px;height:40px;border-radius:12px;display:grid;place-items:center;flex:none}
.float b{display:block;font-size:14px;color:var(--navy)}
.float small{color:var(--muted)}
.float--1{left:-40px;top:14%}
.float--2{right:-30px;bottom:22%}
.float--3{left:-20px;bottom:-16px}

.trust{padding:24px 0;border-block:1px solid var(--line);margin-top:40px}
.trust__in{display:flex;align-items:center;justify-content:space-between;gap:30px;flex-wrap:wrap}
.trust__in > span{font-size:13px;color:var(--muted);font-weight:600}
.trust__logos{display:flex;gap:34px;flex-wrap:wrap;font-weight:800;font-size:15px;color:#B0BAC9;letter-spacing:1px}

/* ---------- Section ---------- */
.section{padding:90px 0}
.section--soft{background:var(--bg-2)}
.section--navy{background:var(--navy);color:#fff}
.section--navy h2,.section--navy h3{color:#fff}
.section__head{max-width:680px;margin:0 auto 50px;text-align:center}
.section__head .eyebrow{margin-bottom:16px}
.section__title{font-size:clamp(28px,3.8vw,42px)}
.section__head p{color:var(--muted);margin-top:14px;font-size:17px}
.section--navy .section__head p{color:rgba(255,255,255,.75)}

/* ---------- Vấn đề ---------- */
.pains{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.pain{background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);padding:30px;position:relative}
.pain .x{width:44px;height:44px;border-radius:12px;background:#FEE2E2;color:var(--red);display:grid;place-items:center;margin-bottom:18px}
.pain h3{font-size:19px;margin-bottom:8px}
.pain p{color:var(--muted);font-size:15px}
.pains + .pivot{text-align:center;margin-top:44px;font-size:22px;font-weight:800;color:var(--navy)}
.pivot span{color:var(--blue)}

/* ---------- Giải pháp: lộ trình ---------- */
.path{display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center}
.path .ph{aspect-ratio:4/3;border-radius:var(--radius-lg);box-shadow:var(--shadow-lg)}
.steps{display:grid;gap:18px}
.step{display:flex;gap:16px;align-items:flex-start;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px}
.step span{width:40px;height:40px;border-radius:12px;background:var(--gold);color:var(--navy);display:grid;place-items:center;font-weight:800;flex:none}
.step b{display:block;color:var(--navy);font-size:16px}
.step small{color:var(--muted);font-size:14px}

/* ---------- Kết quả số ---------- */
.results{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;text-align:center}
.result b{display:block;font-size:44px;font-weight:800;color:var(--gold);line-height:1}
.result span{display:block;margin-top:8px;font-size:14px;opacity:.8}

/* ---------- Chứng thực slider ---------- */
.testi{display:flex;gap:20px;overflow-x:auto;scroll-snap-type:x mandatory;scrollbar-width:none;padding:6px 0 20px;margin-inline:calc(50% - 50vw);padding-inline:calc(50vw - 50%)}
.testi::-webkit-scrollbar{display:none}
.tcard{flex:none;width:380px;scroll-snap-align:start;background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);padding:26px;display:flex;flex-direction:column}
.tcard .stars{font-size:14px;margin-bottom:10px}
.tcard p{font-size:15px;flex:1}
.tcard__who{display:flex;align-items:center;gap:12px;margin-top:20px;padding-top:16px;border-top:1px solid var(--line)}
.tcard__who .ph{width:46px;height:46px;border-radius:50%}
.tcard__who b{display:block;font-size:14px;color:var(--navy)}
.tcard__who small{color:var(--muted);font-size:12.5px}
.tcard__result{background:var(--blue-soft);color:var(--blue);font-weight:700;font-size:13px;padding:6px 12px;border-radius:999px;align-self:flex-start;margin-bottom:12px}

/* ---------- Nội dung khóa (accordion) ---------- */
.curr{max-width:820px;margin-inline:auto}
.curr details{background:#fff;border:1px solid var(--line);border-radius:var(--radius);margin-bottom:12px;overflow:hidden}
.curr summary{list-style:none;cursor:pointer;padding:18px 22px;display:flex;align-items:center;gap:14px;font-weight:700;color:var(--navy)}
.curr summary::-webkit-details-marker{display:none}
.curr summary .n{width:34px;height:34px;border-radius:10px;background:var(--blue-soft);color:var(--blue);display:grid;place-items:center;font-size:13px;flex:none}
.curr summary small{margin-left:auto;color:var(--muted);font-weight:500;font-size:13px;white-space:nowrap}
.curr summary svg{transition:.2s;color:var(--muted)}
.curr details[open] summary svg{transform:rotate(180deg)}
.curr ul{list-style:none;padding:0 22px 18px 70px;display:grid;gap:8px;font-size:14.5px}
.curr li{display:flex;justify-content:space-between;gap:12px;color:var(--muted)}
.curr li::before{content:"▶";font-size:9px;color:var(--blue);margin-right:8px;margin-top:6px}
.curr li span:first-child{flex:1}

/* ---------- Giảng viên ---------- */
.mentor{display:grid;grid-template-columns:2fr 3fr;gap:50px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);padding:40px;box-shadow:var(--shadow)}
.mentor .ph{aspect-ratio:4/5;border-radius:var(--radius)}
.mentor h3{font-size:28px}
.mentor .role{color:var(--blue);font-weight:700;margin:6px 0 16px}
.mentor p{color:var(--muted);margin-bottom:12px}
.mentor ul{list-style:none;display:grid;gap:8px;margin-top:16px}
.mentor li{display:flex;gap:10px;font-size:15px}
.mentor li svg{color:var(--green)}

/* ---------- Giá ---------- */
.plans{display:grid;grid-template-columns:1fr 1fr;gap:24px;max-width:860px;margin-inline:auto}
.plan{background:#fff;border:2px solid var(--line);border-radius:var(--radius-lg);padding:36px;display:flex;flex-direction:column;position:relative}
.plan--hot{border-color:var(--gold);box-shadow:var(--shadow-lg)}
.plan__tag{position:absolute;top:-14px;left:50%;transform:translateX(-50%);background:var(--gold);color:var(--navy);font-weight:800;font-size:12px;padding:6px 16px;border-radius:999px;white-space:nowrap}
.plan h3{font-size:22px}
.plan .desc{color:var(--muted);font-size:14px;margin-top:4px}
.plan__price{margin:22px 0 4px;display:flex;align-items:baseline;gap:10px;flex-wrap:wrap}
.plan__price b{font-size:44px;font-weight:800;color:var(--navy);line-height:1}
.plan__price s{color:var(--muted);font-size:18px}
.plan__price i{font-style:normal;background:#DCFCE7;color:var(--green);font-weight:700;font-size:13px;padding:3px 10px;border-radius:999px}
.plan .per{color:var(--muted);font-size:13px}
.plan ul{list-style:none;display:grid;gap:11px;margin:26px 0 30px;font-size:15px}
.plan li{display:flex;gap:10px;align-items:flex-start}
.plan li svg{color:var(--green);width:18px;height:18px;margin-top:3px}
.plan li.off{color:var(--muted)}
.plan li.off svg{color:#CBD5E1}
.plan .btn{margin-top:auto;width:100%}
.guarantee{display:flex;gap:16px;align-items:center;max-width:860px;margin:30px auto 0;background:var(--blue-soft);border-radius:var(--radius);padding:20px 24px}
.guarantee svg{width:40px;height:40px;color:var(--blue)}
.guarantee b{display:block;color:var(--navy)}
.guarantee small{color:var(--muted);font-size:14px}

/* ---------- FAQ ---------- */
.faq{max-width:820px;margin-inline:auto}
.faq details{border-bottom:1px solid var(--line);padding:18px 0}
.faq summary{list-style:none;cursor:pointer;display:flex;justify-content:space-between;gap:16px;font-weight:700;color:var(--navy);font-size:17px}
.faq summary::-webkit-details-marker{display:none}
.faq summary span{width:28px;height:28px;border-radius:50%;background:var(--blue-soft);color:var(--blue);display:grid;place-items:center;flex:none;font-size:20px;transition:.2s}
.faq details[open] summary span{transform:rotate(45deg)}
.faq details p{color:var(--muted);margin-top:12px;font-size:15px}

/* ---------- CTA cuối ---------- */
.final{text-align:center;max-width:760px;margin-inline:auto}
.final h2{font-size:clamp(30px,4.4vw,48px)}
.final p{font-size:18px;opacity:.85;margin:16px 0 30px}
.final small{display:block;margin-top:16px;opacity:.7;font-size:13.5px}

/* ---------- Thanh CTA dính đáy ---------- */
.sticky{position:fixed;left:0;right:0;bottom:0;z-index:60;background:#fff;border-top:1px solid var(--line);box-shadow:0 -10px 30px rgba(11,37,69,.12);transform:translateY(110%);transition:.3s}
.sticky.is-on{transform:none}
.sticky__in{display:flex;align-items:center;justify-content:space-between;gap:20px;min-height:72px}
.sticky__in b{color:var(--navy)}
.sticky__in small{display:block;color:var(--muted);font-size:13px}
.countdown{display:flex;gap:6px;align-items:center;font-size:13px;color:var(--muted)}
.countdown span{background:var(--navy);color:#fff;font-weight:800;font-size:14px;padding:4px 8px;border-radius:6px;min-width:34px;text-align:center}

/* ---------- Footer ---------- */
.footer{padding:40px 0 100px;border-top:1px solid var(--line);font-size:13.5px;color:var(--muted)}
.footer__in{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}
.footer a:hover{color:var(--navy)}

/* ---------- Responsive ---------- */
@media (max-width:1100px){
  .float--1{left:0}.float--2{right:0}
}
@media (max-width:980px){
  .anchors{display:none}
  .hero__in{grid-template-columns:1fr;gap:50px}
  .hero__art{max-width:460px;margin-inline:auto;width:100%}
  .pains{grid-template-columns:1fr}
  .path{grid-template-columns:1fr}
  .results{grid-template-columns:1fr 1fr}
  .mentor{grid-template-columns:1fr;padding:28px}
  .mentor .ph{max-width:320px}
  .plans{grid-template-columns:1fr}
}
@media (max-width:640px){
  .container{width:min(1140px,100% - 32px)}
  .section{padding:60px 0}
  .hero{padding:44px 0 30px}
  .hero p{font-size:16px}
  .tcard{width:300px}
  .results{grid-template-columns:1fr 1fr}
  .result b{font-size:34px}
  .btn--lg{padding:16px 26px;font-size:16px;width:100%}
  .sticky__in .countdown{display:none}
  .trust__logos{gap:18px;font-size:13px}
  .float--3{display:none}
  .curr ul{padding-left:22px}
}