:root {
  --nen: #f7f7f5; --the: #ffffff; --chu: #16181d; --phu: #5c6370; --vien: #e4e4e0;
  --chinh: #2f5bea; --chinh-chu: #ffffff; --nhat: #eef2ff;
  --meta: #1877f2; --tiktok: #111111; --google: #1a8a3c; --chung: #7a4fd1;
  --tot: #1a7a3a; --tot-nen: #e6f6ec; --canh: #a15c00; --canh-nen: #fff4e0; --xau: #c62828; --xau-nen: #fdecec;
  --bo: 14px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --nen: #0f1115; --the: #171a21; --chu: #eceef2; --phu: #9aa1ad; --vien: #262a33;
    --chinh: #6d8cff; --chinh-chu: #0f1115; --nhat: #1c2340;
    --tiktok: #e5e5e5;
    --tot: #6fd394; --tot-nen: #163322; --canh: #f0b45a; --canh-nen: #33270f; --xau: #ff8a80; --xau-nen: #3a1717;
  }
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--nen); color: var(--chu);
  font: 16px/1.6 "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", sans-serif;
}
a { color: var(--chinh); text-decoration: none; }
.khung { max-width: 1080px; margin: 0 auto; padding: 0 16px; }
[hidden] { display: none !important; }

/* ===== Đầu trang ===== */
header.dau { border-bottom: 1px solid var(--vien); background: var(--the); position: sticky; top: 0; z-index: 10; }
header.dau .khung { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: 12px; }
.logo { font-weight: 800; font-size: 20px; color: var(--chu); letter-spacing: -0.5px; white-space: nowrap; }
.logo span { color: var(--chinh); }
nav.menu { display: flex; align-items: center; gap: 20px; }
nav.menu a.lien { color: var(--phu); font-weight: 600; font-size: 15px; }
nav.menu a.lien.dang { color: var(--chu); }
@media (max-width: 640px) { nav.menu a.lien { display: none; } }

.bang-demo {
  background: var(--canh-nen); color: var(--canh); font-size: 13px; text-align: center; padding: 6px 16px;
}

/* ===== Nút ===== */
.nut {
  display: inline-block; border: 0; cursor: pointer; font: inherit; font-weight: 600; text-align: center;
  padding: 10px 18px; border-radius: 10px; background: var(--chinh); color: var(--chinh-chu);
}
.nut.phu { background: transparent; color: var(--chu); border: 1px solid var(--vien); }
.nut.nho { padding: 6px 12px; font-size: 14px; border-radius: 8px; }
.nut.do { background: var(--xau); color: #fff; }
.nut.rong { width: 100%; }
.nut:disabled { opacity: .5; cursor: default; }

/* ===== Trang chủ ===== */
.hero { padding: 72px 0 48px; }
.hero h1 { font-size: clamp(32px, 6vw, 52px); line-height: 1.12; margin: 0 0 16px; letter-spacing: -1px; }
.hero p { font-size: 18px; color: var(--phu); max-width: 640px; margin: 0 0 28px; }
.hero .nut { margin: 0 8px 8px 0; }

.buoc { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; margin: 0 0 56px; }
.buoc div { background: var(--the); border: 1px solid var(--vien); border-radius: var(--bo); padding: 20px; }
.buoc b { display: block; color: var(--chinh); font-size: 13px; margin-bottom: 4px; }

h2 { font-size: 26px; margin: 0 0 16px; letter-spacing: -0.5px; }
.muc { margin-top: 72px; }
.loc { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.loc button {
  font: inherit; font-size: 14px; padding: 6px 14px; border-radius: 99px; cursor: pointer;
  border: 1px solid var(--vien); background: var(--the); color: var(--chu);
}
.loc button.chon { background: var(--chu); color: var(--nen); border-color: var(--chu); }

.luoi { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(300px, 100%), 1fr)); gap: 16px; }
.the-skill {
  background: var(--the); border: 1px solid var(--vien); border-radius: var(--bo); padding: 20px;
  display: flex; flex-direction: column; gap: 8px; color: var(--chu); transition: border-color .15s, transform .15s;
}
a.the-skill:hover { border-color: var(--chinh); transform: translateY(-2px); }
.the-skill h3 { margin: 0; font-size: 18px; line-height: 1.35; }
.the-skill p { margin: 0; color: var(--phu); font-size: 15px; flex: 1; }
.the-skill .chan { font-size: 13px; color: var(--phu); }

.nhan { display: flex; gap: 6px; flex-wrap: wrap; }
.nhan span, .tag { font-size: 12px; font-weight: 700; padding: 2px 8px; border-radius: 6px; background: var(--nhat); display: inline-block; }
.META { color: var(--meta); } .TIKTOK { color: var(--tiktok); }
.GOOGLE { color: var(--google); } .CHUNG { color: var(--chung); }
.tag.FREE, .nhan .FREE { background: var(--tot-nen); color: var(--tot); }
.tag.PRO { color: var(--chinh); }
.tag.VIP { background: #fdf0d5; color: #8a5a00; }
@media (prefers-color-scheme: dark) { .tag.VIP { background: #3a2c0c; color: #f0c060; } }
.tag.tot { background: var(--tot-nen); color: var(--tot); }
.tag.canh { background: var(--canh-nen); color: var(--canh); }
.tag.xau { background: var(--xau-nen); color: var(--xau); }
.tag.xam { background: var(--vien); color: var(--phu); }

/* ===== Bảng giá ===== */
.chuyen-ky { display: inline-flex; background: var(--the); border: 1px solid var(--vien); border-radius: 99px; padding: 4px; margin-bottom: 20px; }
.chuyen-ky button { font: inherit; font-size: 14px; font-weight: 600; border: 0; background: transparent; color: var(--phu); padding: 6px 16px; border-radius: 99px; cursor: pointer; }
.chuyen-ky button.chon { background: var(--chu); color: var(--nen); }
.bang-gia { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.bang-gia > div { background: var(--the); border: 1px solid var(--vien); border-radius: var(--bo); padding: 24px; display: flex; flex-direction: column; }
.bang-gia .noi { border: 2px solid var(--chinh); position: relative; }
.bang-gia .noi::before { content: 'Phổ biến'; position: absolute; top: -12px; left: 20px; background: var(--chinh); color: var(--chinh-chu); font-size: 12px; font-weight: 700; padding: 2px 10px; border-radius: 99px; }
.bang-gia .gia { font-size: 30px; font-weight: 800; margin: 8px 0 4px; }
.bang-gia .gia small { font-size: 15px; font-weight: 400; color: var(--phu); }
.bang-gia .ghi { font-size: 13px; color: var(--phu); min-height: 20px; margin-bottom: 12px; }
.bang-gia ul { padding-left: 20px; color: var(--phu); margin: 0 0 20px; flex: 1; }

/* ===== Hộp / thẻ chung ===== */
.hop { max-width: 420px; margin: 64px auto; background: var(--the); border: 1px solid var(--vien); border-radius: var(--bo); padding: 28px; }
.hop h1 { font-size: 24px; margin: 0 0 8px; }
.hop > p { color: var(--phu); margin: 0 0 20px; }
.the { background: var(--the); border: 1px solid var(--vien); border-radius: var(--bo); padding: 24px; }
.the h3 { margin: 0 0 12px; font-size: 17px; }
.the + .the { margin-top: 16px; }
.mo { color: var(--phu); font-size: 14px; }

input, select, textarea {
  width: 100%; font: inherit; padding: 12px 14px; border-radius: 10px;
  border: 1px solid var(--vien); background: var(--nen); color: var(--chu); margin-bottom: 12px;
}
textarea { min-height: 140px; font-family: ui-monospace, Consolas, monospace; font-size: 14px; }
label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 6px; }
input.ma { font-size: 24px; letter-spacing: 8px; text-align: center; }
.thong-bao { min-height: 24px; font-size: 14px; margin-top: 10px; }
.thong-bao.loi { color: var(--xau); }
.thong-bao.tot { color: var(--tot); }
.dong { display: flex; justify-content: space-between; gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--vien); }
.dong:last-child { border-bottom: 0; }
.dong > span:first-child { color: var(--phu); }
.dong.tong { font-weight: 800; font-size: 18px; }

/* ===== Bố cục 2 cột ===== */
.hai-cot { display: grid; grid-template-columns: minmax(0, 1fr) 340px; gap: 24px; margin: 40px 0 72px; align-items: start; }
.hai-cot .ben { position: sticky; top: 88px; }
@media (max-width: 860px) { .hai-cot { grid-template-columns: 1fr; } .hai-cot .ben { position: static; } }

/* ===== Chi tiết skill ===== */
.duong-dan { font-size: 14px; color: var(--phu); margin: 32px 0 0; }
.chi-tiet h1 { font-size: clamp(28px, 5vw, 40px); line-height: 1.15; margin: 12px 0; letter-spacing: -0.5px; }
.chi-tiet .dan { font-size: 18px; color: var(--phu); margin: 0 0 24px; }
.chi-tiet ul { padding-left: 20px; margin: 0; }
.chi-tiet li + li { margin-top: 6px; }
.phien-ban { border-left: 2px solid var(--vien); padding-left: 16px; }
.phien-ban div + div { margin-top: 14px; }
.phien-ban b { display: block; }

/* ===== Tài khoản ===== */
.chao { margin: 40px 0 24px; }
.chao h1 { margin: 0; font-size: 28px; }
.luoi-tk { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(320px, 100%), 1fr)); gap: 16px; margin-bottom: 72px; }
.luoi-tk .rong-het { grid-column: 1 / -1; }
.o-link { display: flex; gap: 8px; align-items: center; background: var(--nen); border: 1px solid var(--vien); border-radius: 10px; padding: 10px 12px; font-family: ui-monospace, Consolas, monospace; font-size: 14px; overflow: hidden; }
.o-link span { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
ol.huong-dan { padding-left: 20px; margin: 0; color: var(--phu); }
ol.huong-dan li + li { margin-top: 6px; }
ol.huong-dan b { color: var(--chu); }
.khoa-vip { text-align: center; padding: 8px 0; }

/* ===== Bảng ===== */
.cuon { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th { text-align: left; color: var(--phu); font-weight: 600; padding: 10px 12px; border-bottom: 1px solid var(--vien); white-space: nowrap; }
td { padding: 12px; border-bottom: 1px solid var(--vien); vertical-align: middle; }
tr:last-child td { border-bottom: 0; }
td.so { text-align: right; font-variant-numeric: tabular-nums; white-space: nowrap; }

/* ===== Thanh toán ===== */
.qr { width: 200px; height: 200px; margin: 0 auto 16px; border: 2px dashed var(--vien); border-radius: 12px; display: grid; place-items: center; text-align: center; color: var(--phu); font-size: 13px; padding: 16px; }
.cho { display: flex; align-items: center; gap: 10px; justify-content: center; color: var(--phu); font-size: 14px; margin-top: 12px; }
.xoay { width: 16px; height: 16px; border: 2px solid var(--vien); border-top-color: var(--chinh); border-radius: 50%; animation: xoay 1s linear infinite; }
@keyframes xoay { to { transform: rotate(360deg); } }
.hang-ma { display: flex; gap: 8px; }
.hang-ma input { margin: 0; }
.chon-goi { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 16px; }
.chon-goi label { border: 2px solid var(--vien); border-radius: 12px; padding: 14px; cursor: pointer; margin: 0; font-weight: 400; }
.chon-goi input { display: none; }
.chon-goi label:has(input:checked) { border-color: var(--chinh); background: var(--nhat); }
.chon-goi b { display: block; font-size: 16px; }

/* ===== Quản trị ===== */
.qt { display: grid; grid-template-columns: 200px minmax(0, 1fr); gap: 24px; margin: 32px 0 72px; }
.qt nav { display: flex; flex-direction: column; gap: 4px; position: sticky; top: 88px; align-self: start; }
.qt nav button { font: inherit; text-align: left; border: 0; background: transparent; color: var(--phu); padding: 8px 12px; border-radius: 8px; cursor: pointer; font-weight: 600; display: flex; justify-content: space-between; }
.qt nav button.chon { background: var(--the); color: var(--chu); box-shadow: 0 0 0 1px var(--vien); }
.qt nav .dem { background: var(--xau); color: #fff; font-size: 12px; border-radius: 99px; padding: 0 7px; }
@media (max-width: 760px) {
  .qt { grid-template-columns: 1fr; }
  .qt nav { flex-direction: row; overflow-x: auto; position: static; }
  .qt nav button { white-space: nowrap; }
}
.so-lieu { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 16px; margin-bottom: 16px; }
.so-lieu .the { padding: 18px; }
.so-lieu .gt { font-size: 28px; font-weight: 800; margin-top: 4px; font-variant-numeric: tabular-nums; }
.thanh { height: 8px; background: var(--vien); border-radius: 99px; overflow: hidden; margin-top: 10px; }
.thanh div { height: 100%; background: var(--chinh); }
.dau-muc { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 16px; flex-wrap: wrap; }
.dau-muc h2 { margin: 0; }

/* ===== Hộp thoại ===== */
.nen-mo { position: fixed; inset: 0; background: rgba(0,0,0,.45); display: grid; place-items: center; padding: 16px; z-index: 50; }
.hop-thoai { background: var(--the); border-radius: var(--bo); padding: 24px; max-width: 460px; width: 100%; }
.hop-thoai h3 { margin: 0 0 12px; }
.hop-thoai .nut-hang { display: flex; gap: 8px; justify-content: flex-end; margin-top: 20px; }

.toast { position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%); background: var(--chu); color: var(--nen); padding: 10px 18px; border-radius: 10px; font-size: 14px; z-index: 60; }

footer { border-top: 1px solid var(--vien); padding: 24px 0; color: var(--phu); font-size: 14px; }
footer .khung { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; }
.tag, .nut.nho, .hang-ma .nut { white-space: nowrap; }