/* Đức Mindmap — Hub trang chủ. Bảng màu "Mùa Đông" + font đã được sếp xác nhận 30/09/2026. */
:root {
  --den:#000000; --trang:#FFFFFF; --ruby:#C70039; --cobalt:#0047AB;
  --bac:#C0C0C0; --graphite:#2F2F2F; --tim:#4B0082;
  --bo-vien: 16px;
  /* Phiên bản rgb của 4 màu trên — dùng để pha lớp mờ (blob) trong các nền gradient tối,
     không thêm màu mới ngoài bảng "Mùa Đông" đã xác nhận. */
  --ruby-rgb: 199,0,57; --cobalt-rgb: 0,71,171; --tim-rgb: 75,0,130; --graphite-rgb: 47,47,47;
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--trang); color: var(--graphite);
  font-family: 'Be Vietnam Pro', Arial, sans-serif; font-size: 17px; line-height: 1.6;
}
h1, h2, h3.tieu-de-lon { font-family: 'Playfair Display', Georgia, serif; margin: 0 0 8px; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 20px; }
a { color: inherit; }
a.the-dinh-huong, a.nut, .the-san-pham a { text-decoration: none; }
img { max-width: 100%; display: block; }

/* Header */
header.site { position: sticky; top: 0; z-index: 20; background: rgba(255,255,255,.96); border-bottom: 1px solid var(--bac); backdrop-filter: blur(6px); }
header.site .wrap { display: flex; align-items: center; justify-content: space-between; padding: 12px 20px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand img { width: 44px; height: 44px; border-radius: 50%; }
.brand .ten { font-family: 'Playfair Display', serif; font-weight: 700; color: var(--cobalt); font-size: 20px; line-height: 1.2; }
.brand .tagline { font-size: 13px; color: var(--graphite); opacity: .8; }
.nut { display: inline-block; font-weight: 600; padding: 10px 20px; border-radius: 8px; text-decoration: none; border: none; cursor: pointer; font-size: 15px; }
.nut-do { background: var(--ruby); color: var(--trang); }
.nut-vien { background: transparent; color: var(--cobalt); border: 1.5px solid var(--cobalt); }
.nut-do:hover { filter: brightness(1.08); }

/* Hero — nền "Mùa Đông" tối có chiều sâu (mesh gradient): nền đen/graphite phối các khối mờ
   ruby/cobalt/tím, tạo cảm giác sang trọng thay vì trắng phẳng như trước. */
.hero {
  padding: 60px 0 46px; text-align: center; position: relative; isolation: isolate;
  background:
    radial-gradient(640px 480px at 88% -14%, rgba(var(--ruby-rgb), .26), transparent 60%),
    radial-gradient(760px 640px at 4% -6%, rgba(var(--tim-rgb), .44), transparent 58%),
    radial-gradient(900px 760px at 50% 122%, rgba(var(--cobalt-rgb), .40), transparent 62%),
    linear-gradient(160deg, var(--den) 0%, var(--graphite) 52%, var(--den) 100%);
}
.hero h1 { font-size: 34px; color: var(--trang); }
.hero .phu-de { font-size: 19px; color: var(--bac); font-weight: 600; margin-bottom: 18px; }
.hero .mota { max-width: 640px; margin: 0 auto 26px; color: rgba(255,255,255,.85); }
.hero .cta-hang { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero .nut-vien { color: var(--trang); border-color: rgba(255,255,255,.55); }
.hero .nut-vien:hover { background: rgba(255,255,255,.1); }
.hero .kinh-nghiem { margin-top: 18px; font-size: 14px; color: rgba(255,255,255,.65); }

/* 4 thẻ định hướng */
section.dinh-huong { padding: 44px 0; }
section.dinh-huong h2 { text-align: center; color: var(--tim); font-size: 26px; }
.luoi-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin-top: 26px; }
.the-dinh-huong { border: 1px solid var(--bac); border-radius: var(--bo-vien); padding: 22px 18px; text-align: left; transition: transform .15s, box-shadow .15s; }
.the-dinh-huong:hover { transform: translateY(-3px); box-shadow: 0 10px 24px rgba(0,0,0,.08); }
.the-dinh-huong .icon { font-size: 28px; margin-bottom: 10px; }
.the-dinh-huong h3 { font-family: 'Be Vietnam Pro'; font-weight: 700; color: var(--cobalt); font-size: 17px; margin: 0 0 6px; }
.the-dinh-huong p { font-size: 14.5px; margin: 0; color: var(--graphite); opacity: .85; }

/* Sản phẩm */
section.san-pham { padding: 44px 0; background: var(--trang); }
section.san-pham h2 { text-align: center; color: var(--tim); font-size: 26px; margin-bottom: 8px; }
.gioi-thieu-nhom { text-align: center; max-width: 680px; margin: 0 auto 30px; opacity: .85; font-size: 15px; }
.luoi-san-pham { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.the-san-pham { border: 1px solid var(--bac); border-radius: var(--bo-vien); padding: 24px 20px; display: flex; flex-direction: column; }
.the-san-pham .nhan { display: inline-block; font-size: 11.5px; font-weight: 700; letter-spacing: .04em; color: var(--trang); background: var(--cobalt); padding: 3px 10px; border-radius: 999px; margin-bottom: 10px; }
.the-san-pham .nhan.sap-co { background: var(--bac); color: var(--graphite); }
.the-san-pham .nhan.mien-phi { background: var(--ruby); }
.the-san-pham h3 { font-family: 'Playfair Display', serif; color: var(--cobalt); font-size: 19px; margin: 0 0 8px; }
.the-san-pham p.mo-ta { font-size: 14.5px; opacity: .9; min-height: 66px; }
.bang-gia { margin: 12px 0; font-size: 14px; }
.bang-gia div { display: flex; justify-content: space-between; padding: 6px 0; border-top: 1px dashed var(--bac); }
.bang-gia div:first-child { border-top: none; }
.gia { font-weight: 700; color: var(--ruby); }
.the-san-pham .nut { margin-top: 12px; width: 100%; text-align: center; }

/* Placeholder / sắp có */
.canh-bao-nhap {
  background: #FFF7E6; border: 1px dashed #E0A100; color: #7a5b00;
  font-size: 13.5px; padding: 8px 12px; border-radius: 8px; margin-top: 10px;
}

/* Kho công cụ sắp có */
section.kho-cong-cu { padding: 44px 0; background: var(--graphite); color: var(--trang); }
section.kho-cong-cu h2 { text-align: center; color: var(--trang); font-size: 26px; }
section.kho-cong-cu .gioi-thieu-nhom { color: var(--bac); }
.luoi-tool { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 24px; }
.o-tool { border: 1px solid #4a4a4a; border-radius: 12px; padding: 16px; opacity: .85; display: block; text-decoration: none; color: inherit; }
.o-tool .icon { font-size: 22px; }
.o-tool h4 { margin: 8px 0 4px; font-size: 14.5px; font-weight: 600; }
.o-tool span.tag { font-size: 11px; color: var(--bac); }
a.o-tool { opacity: 1; border-color: var(--ruby); background: rgba(199,0,57,.12); transition: transform .15s; }
a.o-tool:hover { transform: translateY(-3px); }
a.o-tool span.tag { color: #ffb3c4; font-weight: 700; }

/* Form lắng nghe */
section.lang-nghe { padding: 52px 0; background: var(--tim); color: var(--trang); }
section.lang-nghe .wrap { max-width: 640px; text-align: center; }
section.lang-nghe h2 { color: var(--trang); font-size: 26px; }
section.lang-nghe p { opacity: .92; }
form.form-lang-nghe { text-align: left; margin-top: 24px; display: grid; gap: 12px; }
form.form-lang-nghe textarea, form.form-lang-nghe input {
  width: 100%; padding: 12px 14px; border-radius: 8px; border: none; font-family: inherit; font-size: 15px;
}
form.form-lang-nghe textarea { min-height: 90px; resize: vertical; }
form.form-lang-nghe label.checkbox { display: flex; gap: 8px; font-size: 13px; align-items: flex-start; opacity: .9; }
form.form-lang-nghe .nut-do { align-self: flex-start; padding: 12px 28px; }

/* Footer */
footer.site { background: var(--den); color: var(--bac); padding: 30px 0; text-align: center; font-size: 13.5px; }
footer.site > .wrap > div { margin-top: 10px; }
footer.site > .wrap > div:first-child { margin-top: 0; }
footer.site .zalo { color: var(--trang); font-weight: 600; }
footer.site .mang-xa-hoi { display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; }
footer.site .mang-xa-hoi a { opacity: .85; }
footer.site .mang-xa-hoi a:hover { opacity: 1; text-decoration: underline; }
footer.site .chinh-sach a { opacity: .6; font-size: 12.5px; }
footer.site .chinh-sach a:hover { opacity: .9; }

form.form-lang-nghe label.checkbox a { color: var(--trang); text-decoration: underline; }

/* Trang test / công cụ nhỏ (test-tri-nho.html, test-vak.html) — nền tối "Mùa Đông" có chiều sâu,
   để thẻ trắng .the-test nổi bật ở giữa như một mặt kính sang trọng. */
.trang-test {
  min-height: 100vh; padding-bottom: 40px;
  background:
    radial-gradient(760px 560px at 10% -10%, rgba(var(--ruby-rgb), .30), transparent 60%),
    radial-gradient(820px 680px at 100% 6%, rgba(var(--tim-rgb), .46), transparent 58%),
    radial-gradient(920px 780px at 46% 120%, rgba(var(--cobalt-rgb), .42), transparent 62%),
    linear-gradient(160deg, var(--den) 0%, var(--graphite) 55%, var(--den) 100%);
}
.khung-test { max-width: 640px; margin: 0 auto; padding: 40px 20px; }
.khung-test .quay-lai, .khung-sach .quay-lai {
  display: inline-block; margin-bottom: 18px; font-size: 14px; font-weight: 600;
  color: rgba(255,255,255,.82); text-decoration: none; transition: color .15s;
}
.khung-test .quay-lai:hover, .khung-sach .quay-lai:hover { color: var(--trang); text-decoration: underline; }
.the-test {
  background: var(--trang); border: 1px solid var(--bac); border-radius: 18px; padding: 28px 26px;
  box-shadow: 0 24px 70px rgba(0,0,0,.5), 0 6px 18px rgba(0,0,0,.25);
}
.the-test h1 { font-size: 26px; color: var(--cobalt); }
.the-test .gioi-thieu { opacity: .85; font-size: 15px; margin-bottom: 18px; }
.the-test .disclaimer { font-size: 12.5px; opacity: .7; margin-top: 18px; border-top: 1px dashed var(--bac); padding-top: 12px; }
.cau-hoi { margin-bottom: 22px; }
.cau-hoi .so-cau { font-weight: 700; color: var(--tim); font-size: 13px; margin-bottom: 4px; }
.cau-hoi .noi-dung { font-weight: 600; margin-bottom: 10px; }
.lua-chon {
  display: block; border: 1.5px solid var(--bac); border-radius: 10px; padding: 12px 14px;
  margin-bottom: 8px; cursor: pointer; font-size: 14.5px; transition: border-color .15s, background .15s;
}
.lua-chon:hover { border-color: var(--cobalt); }
.lua-chon input { margin-right: 10px; accent-color: var(--cobalt); transform: scale(1.15); vertical-align: middle; }
.lua-chon:has(input:checked) {
  border-color: var(--cobalt); background: rgba(0, 71, 171, 0.07); font-weight: 600; color: var(--cobalt);
}
.trinh-tu-so { font-family: 'Playfair Display', serif; font-size: 52px; text-align: center; letter-spacing: 10px; color: var(--cobalt); margin: 30px 0; min-height: 70px; }
.o-nhap-test { width: 100%; padding: 14px; font-size: 20px; text-align: center; letter-spacing: 4px; border: 1.5px solid var(--bac); border-radius: 10px; margin-bottom: 14px; }
.ket-qua { text-align: center; padding: 10px 0; }
.ket-qua .diem { font-family: 'Playfair Display', serif; font-size: 40px; color: var(--ruby); }
.ket-qua h2 { color: var(--tim); }
.nhan-cap { text-align: center; font-size: 13px; opacity: .7; margin-bottom: 6px; }
.thanh-tien-do { height: 8px; background: #eee; border-radius: 999px; overflow: hidden; margin-top: 14px; }
.thanh-tien-do-fill { height: 100%; width: 0%; background: var(--ruby); transition: width .25s ease; }

/* Sách lật (test-tri-nho dùng .trang-test; sách dùng khung riêng) — cùng tinh thần nền tối
   "Mùa Đông" như .trang-test, đổi vị trí/độ đậm các khối mờ một chút để có nhịp riêng. */
.trang-sach {
  min-height: 100vh; padding-bottom: 40px;
  background:
    radial-gradient(700px 560px at 92% -8%, rgba(var(--cobalt-rgb), .40), transparent 60%),
    radial-gradient(680px 600px at 4% 8%, rgba(var(--tim-rgb), .34), transparent 58%),
    radial-gradient(820px 700px at 50% 118%, rgba(var(--ruby-rgb), .18), transparent 62%),
    linear-gradient(165deg, var(--den) 0%, var(--graphite) 50%, var(--den) 100%);
}
.khung-sach { max-width: 720px; margin: 0 auto; padding: 40px 20px; }
.bia-sach { text-align: center; margin-bottom: 18px; }
.bia-sach h1 { font-size: 24px; color: var(--trang); margin-bottom: 4px; text-shadow: 0 2px 18px rgba(0,0,0,.4); }
.bia-sach .gia-sach { display: inline-block; background: var(--ruby); color: #fff; font-weight: 700; padding: 4px 14px; border-radius: 999px; font-size: 13px; box-shadow: 0 6px 18px rgba(199,0,57,.4); }
/* Thanh điều hướng trang sách (← Trang trước / Trang sau →) nằm NGOÀI thẻ trắng .the-sach,
   nên phải tự đặt màu sáng riêng để đọc được trên nền tối — không dùng chung màu cobalt/graphite
   vốn thiết kế cho nền sáng. */
.khung-sach .dieu-huong-sach .nut-vien { color: var(--trang); border-color: rgba(255,255,255,.55); }
.khung-sach .dieu-huong-sach .nut-vien:hover { background: rgba(255,255,255,.1); }
.khung-sach .dieu-huong-sach .so-trang { color: rgba(255,255,255,.75); }
.the-sach {
  background: var(--trang); border-radius: 6px 18px 18px 6px; border: 1px solid var(--bac);
  box-shadow: -8px 0 0 -2px #eee, 0 26px 70px rgba(0,0,0,.48);
  padding: 36px 40px; min-height: 420px; position: relative;
  font-family: 'Lora', Georgia, serif; font-size: 17px; line-height: 1.75; color: var(--den);
}
.the-sach::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 6px; background: linear-gradient(90deg, rgba(0,0,0,.12), transparent); }
.the-sach h3 { font-family: 'Playfair Display', serif; color: var(--tim); font-size: 20px; margin-top: 0; }
.dieu-huong-sach { display: flex; align-items: center; justify-content: space-between; margin-top: 18px; }
.dieu-huong-sach .so-trang { font-size: 13.5px; opacity: .7; font-family: 'Be Vietnam Pro', sans-serif; }
.man-tra-phi { text-align: center; }
.man-tra-phi h3 { color: var(--tim); font-size: 22px; }
.man-tra-phi .gia-lon { font-family: 'Playfair Display', serif; font-size: 34px; color: var(--ruby); margin: 10px 0; }
/* Anh kich thuoc file PNG da resize san (320x379) khop voi max-width nay,
   de trinh duyet KHONG phai co gian them - co gian ty le le se gay nhieu moire
   tren ma QR (da xac nhan qua thuc te, tung bi vo hinh khi de trinh duyet tu co). */
.qr-thanh-toan { max-width: 320px; width: 100%; margin: 4px auto 14px; display: block; border-radius: 14px; border: 1px solid var(--bac); box-shadow: 0 10px 28px rgba(0,0,0,.12); }

@media (max-width: 860px) {
  .the-sach { padding: 26px 22px; }
}

/* Phản hồi đúng/sai cho các test có chấm điểm (test-tri-nho.html) */
@keyframes rung-sai-kf {
  10%, 90% { transform: translateX(-2px); }
  20%, 80% { transform: translateX(4px); }
  30%, 50%, 70% { transform: translateX(-8px); }
  40%, 60% { transform: translateX(8px); }
}
.rung-sai { animation: rung-sai-kf 0.5s; border-color: var(--ruby) !important; }
@keyframes chop-so-pulse-kf {
  0% { transform: scale(1.3); opacity: .35; }
  100% { transform: scale(1); opacity: 1; }
}
.chop-so-pulse { animation: chop-so-pulse-kf 0.18s ease-out; }
.dap-an-badge {
  display: inline-block; font-family: 'Be Vietnam Pro', Arial, sans-serif; font-weight: 700;
  font-size: 16px; background: var(--graphite); color: var(--trang);
  padding: 3px 12px; border-radius: 999px; margin-left: 4px; letter-spacing: .5px;
}
#canvas-phao-hoa { position: fixed; inset: 0; pointer-events: none; z-index: 9999; }
@media (max-width: 860px) {
  .luoi-4, .luoi-san-pham, .luoi-tool { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .luoi-4, .luoi-san-pham, .luoi-tool { grid-template-columns: 1fr; }
  header.site .wrap { flex-direction: column; gap: 10px; }
  .hero h1 { font-size: 26px; }
}