:root {
  --nen: #fffaf4;
  --nen-2: #fff1e3;
  --the: #ffffff;
  --chu: #2b2320;
  --chu-nhat: #6b5e57;
  --cam: #e8590c;
  --cam-dam: #c2410c;
  --do: #c92a2a;
  --vien: #f1dfcf;
  --xanh-zalo: #0068ff;
  --xanh-fb: #1877f2;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--nen);
  color: var(--chu);
  font-family: "Be Vietnam Pro", system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.65;
}
img { max-width: 100%; display: block; }
a { color: var(--cam-dam); }
.khung { max-width: 1040px; margin: 0 auto; padding: 0 16px; }

/* Đầu trang */
.dau {
  background: linear-gradient(160deg, #fff3e6 0%, #ffe3c9 100%);
  padding: 28px 0 40px;
}
.dau .khung { display: grid; gap: 24px; align-items: center; }
.anh-dau {
  border-radius: 22px;
  overflow: hidden;
  box-shadow: 0 18px 40px -18px rgba(150, 60, 10, .45);
  aspect-ratio: 4 / 5;
}
.anh-dau img { width: 100%; height: 100%; object-fit: cover; object-position: 50% 62%; }
.nhan {
  display: inline-block;
  background: var(--the);
  color: var(--cam-dam);
  font-weight: 600;
  font-size: 14px;
  padding: 5px 12px;
  border-radius: 99px;
  border: 1px solid var(--vien);
}
h1 {
  font-size: clamp(34px, 8vw, 54px);
  line-height: 1.1;
  margin: 12px 0 10px;
  font-weight: 800;
  letter-spacing: -.02em;
}
h1 span { color: var(--cam); }
.mo-ta { font-size: 18px; color: var(--chu-nhat); margin: 0 0 22px; }
.nut-hang { display: flex; flex-wrap: wrap; gap: 10px; }
.nut {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 20px;
  border-radius: 12px;
  font-weight: 700;
  text-decoration: none;
  font-size: 16px;
}
.nut svg { width: 20px; height: 20px; flex: none; }
.nut-chinh { background: var(--cam); color: #fff; }
.nut-chinh:hover { background: var(--cam-dam); }
.nut-phu { background: var(--the); color: var(--chu); border: 1px solid var(--vien); }

/* Con số */
.so-lieu {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-top: -22px;
  position: relative;
}
.so {
  background: var(--the);
  border: 1px solid var(--vien);
  border-radius: 16px;
  padding: 14px 16px;
}
.so b { display: block; font-size: 28px; line-height: 1.1; color: var(--cam-dam); font-weight: 800; }
.so span { font-size: 14px; color: var(--chu-nhat); }

section { padding: 48px 0 8px; }
h2 {
  font-size: clamp(26px, 5.5vw, 36px);
  line-height: 1.2;
  margin: 0 0 16px;
  font-weight: 800;
  letter-spacing: -.01em;
}
.tieu-de-nho {
  color: var(--cam);
  font-weight: 700;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: .08em;
  margin: 0 0 6px;
}
p { margin: 0 0 14px; }

blockquote {
  margin: 20px 0;
  padding: 18px 20px;
  background: var(--nen-2);
  border-left: 4px solid var(--cam);
  border-radius: 0 14px 14px 0;
  font-family: "Lora", Georgia, serif;
  font-style: italic;
  font-size: 19px;
  line-height: 1.55;
}
blockquote cite { display: block; margin-top: 8px; font-style: normal; font-family: "Be Vietnam Pro", sans-serif; font-size: 14px; color: var(--chu-nhat); }

.hai-cot { display: grid; gap: 24px; align-items: start; }
.anh-bo { border-radius: 16px; overflow: hidden; border: 1px solid var(--vien); background: var(--the); }
.anh-bo figcaption { padding: 10px 14px; font-size: 14px; color: var(--chu-nhat); }

/* Các lớp */
.lop-luoi { display: grid; gap: 12px; }
.lop {
  background: var(--the);
  border: 1px solid var(--vien);
  border-radius: 16px;
  padding: 16px 18px;
}
.lop h3 { margin: 0 0 4px; font-size: 18px; }
.lop p { margin: 0; color: var(--chu-nhat); font-size: 15.5px; }

.anh-doi { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 20px; }

/* Cách dạy */
.diem { display: grid; gap: 14px; }
.diem > div {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 14px;
  align-items: start;
}
.diem i {
  width: 44px; height: 44px;
  border-radius: 12px;
  background: var(--nen-2);
  color: var(--cam-dam);
  display: grid; place-items: center;
  font-style: normal; font-weight: 800; font-size: 18px;
}
.diem h3 { margin: 0 0 2px; font-size: 18px; }
.diem p { margin: 0; color: var(--chu-nhat); }

/* Sách */
.sach { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }

/* Liên hệ */
.lien-he {
  margin: 56px 0 0;
  background: linear-gradient(150deg, var(--cam) 0%, var(--do) 100%);
  color: #fff;
  padding: 44px 0 40px;
}
.lien-he h2 { color: #fff; }
.lien-he p { color: #ffeede; }
.lh-luoi { display: grid; gap: 10px; margin-top: 18px; }
.lh {
  display: flex; align-items: center; gap: 14px;
  background: rgba(255,255,255,.12);
  border: 1px solid rgba(255,255,255,.25);
  border-radius: 14px;
  padding: 14px 16px;
  color: #fff;
  text-decoration: none;
}
.lh:hover { background: rgba(255,255,255,.2); }
.lh svg { width: 26px; height: 26px; flex: none; }
.lh b { display: block; font-size: 17px; }
.lh span { font-size: 14px; color: #ffe4cf; }
footer { text-align: center; padding: 22px 16px 90px; font-size: 13px; color: var(--chu-nhat); }

/* Nút gọi dính dưới đáy trên điện thoại */
.goi-nhanh {
  position: fixed; left: 12px; right: 12px; bottom: 12px;
  display: grid; grid-template-columns: 1fr 1fr; gap: 8px;
  z-index: 10;
}
.goi-nhanh a {
  display: flex; align-items: center; justify-content: center; gap: 8px;
  padding: 13px; border-radius: 12px;
  color: #fff; font-weight: 700; text-decoration: none;
  box-shadow: 0 8px 22px -8px rgba(0,0,0,.4);
}
.goi-nhanh svg { width: 20px; height: 20px; }
.goi-nhanh .g { background: var(--cam); }
.goi-nhanh .z { background: var(--xanh-zalo); }

@media (min-width: 760px) {
  body { font-size: 18px; }
  .dau { padding: 48px 0 64px; }
  .dau .khung { grid-template-columns: 1.1fr .9fr; gap: 48px; }
  .so-lieu { grid-template-columns: repeat(4, 1fr); margin-top: -30px; }
  .hai-cot { grid-template-columns: 1.2fr .8fr; gap: 40px; }
  .hai-cot.dao { grid-template-columns: .8fr 1.2fr; }
  .lop-luoi { grid-template-columns: 1fr 1fr; }
  .lh-luoi { grid-template-columns: repeat(3, 1fr); }
  .goi-nhanh { display: none; }
  footer { padding-bottom: 28px; }
}

/* Thanh menu */
.menu { background: var(--the); border-bottom: 1px solid var(--vien); position: sticky; top: 0; z-index: 20; }
.menu .khung { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; padding-top: 10px; padding-bottom: 10px; }
.ten { font-weight: 800; color: var(--chu); text-decoration: none; font-size: 18px; }
.ten span { color: var(--cam); }
.menu nav { display: flex; flex-wrap: wrap; gap: 4px 16px; font-size: 15px; }
.menu nav a { color: var(--chu-nhat); text-decoration: none; font-weight: 600; padding: 2px 0; }
.menu nav a:hover, .menu nav a[aria-current] { color: var(--cam-dam); }
.dau-nho { background: linear-gradient(160deg, #fff3e6 0%, #ffe3c9 100%); padding: 36px 0 32px; }
.dau-nho h1 { margin-top: 4px; font-size: clamp(30px, 7vw, 44px); }
.dau-nho p { margin: 0; color: var(--chu-nhat); max-width: 680px; }
.the-lon { background: var(--the); border: 1px solid var(--vien); border-radius: 16px; padding: 20px; margin-bottom: 16px; }
.the-lon h3 { margin: 0 0 8px; font-size: 20px; }
.the-lon ul { margin: 0; padding-left: 20px; }
.gia { color: var(--cam-dam); font-weight: 800; font-size: 22px; margin: 0 0 6px; }
.xem-them { font-weight: 700; }
.moc { display: grid; gap: 14px; }
.moc > div { border-left: 3px solid var(--cam); padding-left: 14px; }
.moc h3 { margin: 0 0 2px; font-size: 18px; }
.moc p { margin: 0; color: var(--chu-nhat); }
.co-so { display: grid; gap: 12px; }
.mot-sach { display: grid; gap: 18px; align-items: start; }
.mot-sach img { border-radius: 16px; }
@media (min-width: 760px) {
  .co-so { grid-template-columns: 1fr 1fr; }
  .mot-sach { grid-template-columns: .8fr 1.2fr; gap: 32px; }
}