/* Dùng chung cho các trang ngoài phần làm bài của dethiai.vn: trang chọn lớp, Giới thiệu, Liên hệ. */
:root { --chinh: #FF7A2F; --chinh-dam: #E8601A; --nen: #FFF8F0; --chu: #2B2B3A; --chu-phu: #6B6B7B; --vien: #E3E3EA; }
* { box-sizing: border-box; }
body { margin: 0; background: var(--nen); color: var(--chu); font: 17px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif; }
a { color: var(--chinh-dam); }
header { background: var(--chinh); color: #fff; }
.dau-trang { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 16px; max-width: 760px; margin: 0 auto; padding: 10px 16px; }
.dau-trang .ten { flex: 1; display: flex; align-items: center; gap: 10px; min-width: 190px; color: #fff; font-size: 19px; font-weight: 600; text-decoration: none; }
.dau-trang .ten img { border-radius: 8px; }
.dau-trang nav { display: flex; flex-wrap: wrap; gap: 4px; }
.dau-trang nav a { padding: 6px 10px; white-space: nowrap; border-radius: 16px; color: #fff; font-size: 15px; text-decoration: none; }
.dau-trang nav a:hover, .dau-trang nav a:focus-visible, .dau-trang nav a[aria-current] { background: rgba(255,255,255,.22); }
main { max-width: 760px; margin: 0 auto; padding: 24px 16px 40px; }
h1 { margin: 0 0 8px; font-size: 28px; }
h2 { margin: 0 0 8px; font-size: 20px; }
p { margin: 0 0 10px; }
.chu-phu { color: var(--chu-phu); }
.the { margin-top: 16px; padding: 18px 20px; background: #fff; border-radius: 18px; box-shadow: 0 2px 8px rgba(0,0,0,.06); }
.the > :last-child { margin-bottom: 0; }
.the ul { margin: 0; padding-left: 22px; } .the li { margin-bottom: 6px; }
.nut { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; padding: 8px 22px; border-radius: 24px; border: 2px solid var(--chinh); background: var(--chinh); color: #fff; font-size: 17px; font-weight: 600; text-decoration: none; }
.nut.phu { background: #fff; color: var(--chinh-dam); }
.hang-nut { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 12px; }
.dong { display: flex; justify-content: space-between; gap: 12px; padding: 8px 0; border-bottom: 1px solid var(--vien); }
.dong:last-of-type { border-bottom: 0; }
.dong > :last-child { text-align: right; font-weight: 600; overflow-wrap: anywhere; min-width: 0; }
/* Trang Hướng dẫn: các bước đánh số. */
ol.buoc { list-style: none; margin: 0; padding: 0; counter-reset: buoc; }
ol.buoc > li { position: relative; margin-top: 16px; padding: 18px 20px 18px 68px; background: #fff; border-radius: 18px; box-shadow: 0 2px 8px rgba(0,0,0,.06); counter-increment: buoc; }
ol.buoc > li::before { content: counter(buoc); position: absolute; left: 18px; top: 18px; width: 36px; height: 36px; border-radius: 18px; background: var(--chinh); color: #fff; font-weight: 600; line-height: 36px; text-align: center; }
ol.buoc > li > :last-child { margin-bottom: 0; }
ol.buoc ul { margin: 0 0 10px; padding-left: 20px; } ol.buoc ul li { margin-bottom: 4px; }
footer { max-width: 760px; margin: 0 auto; padding: 0 16px 32px; font-size: 14px; text-align: center; color: var(--chu-phu); }