:root {
  --nen: #f4f7f5;
  --the: #ffffff;
  --chu: #17201c;
  --phu: #5d6b64;
  --vien: #e1e8e4;
  --chinh: #0f766e;
  --chinh-nhat: #e3f3f0;
  --chinh-dam: #0b5952;
  --tren-chinh: #ffffff;
  --nhan: #d97706;
  --nhan-nhat: #fdf3e2;
  --do: #c2410c;
  --do-nhat: #fdece4;
  --xanh-la: #15803d;
  --bo: 16px;
  --bong: 0 1px 2px rgba(16, 40, 32, .06), 0 4px 16px rgba(16, 40, 32, .05);
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --nen: #0f1513; --the: #18211e; --chu: #e8efeb; --phu: #9aa9a2; --vien: #2a3631;
    --chinh: #2dd4bf; --chinh-nhat: #12332e; --chinh-dam: #5eead4; --tren-chinh: #06201c; --nhan: #fbbf24; --nhan-nhat: #3a2e12;
    --do: #fb923c; --do-nhat: #3b2016; --xanh-la: #4ade80; --bong: none; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --nen: #0f1513; --the: #18211e; --chu: #e8efeb; --phu: #9aa9a2; --vien: #2a3631;
  --chinh: #2dd4bf; --chinh-nhat: #12332e; --chinh-dam: #5eead4; --tren-chinh: #06201c; --nhan: #fbbf24; --nhan-nhat: #3a2e12;
  --do: #fb923c; --do-nhat: #3b2016; --xanh-la: #4ade80; --bong: none; color-scheme: dark;
}
* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--nen); color: var(--chu);
  font: 16px/1.55 "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased; -webkit-tap-highlight-color: transparent;
}
.app { max-width: 560px; margin: 0 auto; padding: 16px 16px calc(96px + env(safe-area-inset-bottom)); min-height: 100vh; }
.loading { padding: 40vh 0; text-align: center; color: var(--phu); }
h1 { font-size: 24px; line-height: 1.25; margin: 4px 0 4px; letter-spacing: -.01em; }
h2 { font-size: 18px; margin: 24px 0 10px; }
h3 { font-size: 16px; margin: 0 0 6px; }
p { margin: 0 0 10px; }
a { color: var(--chinh); }
.phu { color: var(--phu); font-size: 14px; }
.nho { font-size: 13px; }
.dau { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.dau .lui { border: 0; background: var(--the); width: 40px; height: 40px; border-radius: 12px; font-size: 20px; color: var(--chu); box-shadow: var(--bong); cursor: pointer; flex: none; }
.the { background: var(--the); border-radius: var(--bo); padding: 16px; box-shadow: var(--bong); border: 1px solid var(--vien); margin-bottom: 12px; }
.the.noi { background: var(--chinh); color: var(--tren-chinh); border-color: transparent; }
.the.noi .phu { color: var(--tren-chinh); opacity: .82; }
.the.canh { background: var(--nhan-nhat); border-color: transparent; }
.the.do { background: var(--do-nhat); border-color: transparent; }
.hang { display: flex; align-items: center; gap: 12px; }
.hang > .gian { flex: 1; min-width: 0; }
.luoi2 { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.luoi3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.so-lon { font-size: 28px; font-weight: 700; line-height: 1.1; }
.nut {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  border: 0; border-radius: 12px; padding: 12px 18px; font: inherit; font-weight: 600; white-space: nowrap; flex: none;
  background: var(--chinh); color: var(--tren-chinh); cursor: pointer; text-decoration: none; min-height: 46px;
}
.nut.khoi { width: 100%; }
.nut.phu2 { background: var(--chinh-nhat); color: var(--chinh-dam); }
.nut.vien { background: transparent; color: var(--chu); border: 1px solid var(--vien); }
.nut.nguy { background: var(--do); color: #fff; }
.nut.nho { padding: 8px 12px; min-height: 36px; font-size: 14px; border-radius: 10px; }
.nut:disabled { opacity: .5; cursor: not-allowed; }
label { display: block; font-size: 14px; font-weight: 600; margin: 12px 0 6px; }
input, select, textarea {
  width: 100%; font: inherit; color: var(--chu); background: var(--the);
  border: 1px solid var(--vien); border-radius: 12px; padding: 11px 12px; min-height: 46px;
}
textarea { min-height: 100px; resize: vertical; }
input:focus, select:focus, textarea:focus { outline: 2px solid var(--chinh); outline-offset: 0; border-color: transparent; }
.chon { display: flex; align-items: flex-start; gap: 10px; font-weight: 400; margin: 10px 0; }
.chon input { width: 20px; height: 20px; min-height: 0; margin-top: 2px; flex: none; accent-color: var(--chinh); }
.loi { color: var(--do); font-size: 14px; margin-top: 8px; min-height: 1em; }
.the-bai { display: flex; gap: 12px; align-items: center; text-decoration: none; color: inherit; }
.the-bai .so {
  width: 40px; height: 40px; border-radius: 12px; flex: none; display: grid; place-items: center;
  background: var(--chinh-nhat); color: var(--chinh-dam); font-weight: 700;
}
.the-bai.xong .so { background: var(--chinh); color: var(--tren-chinh); }
.the-bai.khoa { opacity: .55; }
.the-bai.khoa .so { background: var(--vien); color: var(--phu); }
.nhan { display: inline-block; font-size: 12px; font-weight: 600; padding: 2px 8px; border-radius: 99px; background: var(--chinh-nhat); color: var(--chinh-dam); }
.nhan.cam { background: var(--nhan-nhat); color: var(--nhan); }
.nhan.do { background: var(--do-nhat); color: var(--do); }
.tuan-tieu { font-size: 13px; font-weight: 700; color: var(--phu); text-transform: uppercase; letter-spacing: .04em; margin: 20px 0 8px; }
.viec { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.viec button {
  border: 1px solid var(--vien); background: var(--the); color: var(--chu); border-radius: 14px;
  padding: 12px 6px; font: inherit; font-size: 13px; font-weight: 500; cursor: pointer; display: grid; gap: 4px; justify-items: center;
}
.viec button .bt { font-size: 22px; line-height: 1; }
.viec button.on { background: var(--chinh); border-color: var(--chinh); color: var(--tren-chinh); }
.thanh { height: 8px; background: var(--vien); border-radius: 99px; overflow: hidden; }
.thanh > i { display: block; height: 100%; background: var(--chinh); border-radius: 99px; }
.the.noi .thanh { background: rgba(255,255,255,.25); }
.the.noi .thanh > i { background: var(--tren-chinh); }
.nhac { display: flex; align-items: center; gap: 12px; padding: 10px 0; border-top: 1px solid var(--vien); }
.nhac:first-of-type { border-top: 0; }
.nhac .gio { font-weight: 700; width: 52px; flex: none; }
.noi-dung { font-size: 16px; }
.noi-dung h1, .noi-dung h2 { font-size: 20px; margin: 18px 0 8px; }
.noi-dung ul { padding-left: 20px; margin: 0 0 12px; }
.noi-dung li { margin: 4px 0; }
.khung-video { position: relative; aspect-ratio: 16 / 9; background: #000; border-radius: var(--bo); overflow: hidden; margin-bottom: 14px; }
.khung-video iframe, .khung-video video { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
audio { width: 100%; margin-bottom: 14px; }
.dap-an { display: block; width: 100%; text-align: left; border: 1px solid var(--vien); background: var(--the); color: var(--chu); border-radius: 12px; padding: 14px; margin: 8px 0; font: inherit; cursor: pointer; }
.dap-an.dung { border-color: var(--xanh-la); background: color-mix(in srgb, var(--xanh-la) 12%, var(--the)); }
.dap-an.sai { border-color: var(--do); background: var(--do-nhat); }
.dap-an:disabled { cursor: default; color: var(--chu); }
.giai-thich { padding: 12px 14px; border-radius: 12px; background: var(--chinh-nhat); margin: 10px 0; font-size: 15px; }
.tabs { display: flex; gap: 6px; background: var(--vien); padding: 4px; border-radius: 12px; margin-bottom: 14px; }
.tabs button { flex: 1; border: 0; background: transparent; padding: 9px; border-radius: 9px; font: inherit; font-weight: 600; font-size: 14px; color: var(--phu); cursor: pointer; }
.tabs button.on { background: var(--the); color: var(--chu); box-shadow: var(--bong); }
.bang { width: 100%; border-collapse: collapse; font-size: 14px; }
.bang td, .bang th { padding: 8px 4px; border-bottom: 1px solid var(--vien); text-align: left; }
.bang td.so, .bang th.so { text-align: right; font-variant-numeric: tabular-nums; }
.anh-luoi { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; }
.anh-luoi img { width: 100%; aspect-ratio: 3 / 4; object-fit: cover; border-radius: 10px; background: var(--vien); }
.cham { display: grid; grid-template-columns: repeat(14, 1fr); gap: 4px; }
.cham i { aspect-ratio: 1; border-radius: 6px; background: var(--vien); }
.cham i.c1 { background: color-mix(in srgb, var(--chinh) 35%, var(--vien)); }
.cham i.c2 { background: color-mix(in srgb, var(--chinh) 65%, var(--vien)); }
.cham i.c3 { background: var(--chinh); }
.nav {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 10;
  background: color-mix(in srgb, var(--the) 94%, transparent); backdrop-filter: blur(10px);
  border-top: 1px solid var(--vien); display: flex; justify-content: center;
  padding: 6px 4px calc(6px + env(safe-area-inset-bottom));
}
.nav a { flex: 1; max-width: 96px; text-align: center; text-decoration: none; color: var(--phu); font-size: 11px; font-weight: 600; padding: 4px 0; display: grid; justify-items: center; gap: 2px; }
.nav a svg { width: 24px; height: 24px; }
.nav a.on { color: var(--chinh); }
.toast { position: fixed; left: 50%; bottom: calc(84px + env(safe-area-inset-bottom)); transform: translateX(-50%); background: var(--chu); color: var(--nen); padding: 10px 16px; border-radius: 12px; font-size: 14px; z-index: 20; max-width: calc(100% - 32px); }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 20px; margin: 24px 0 20px; }
.logo img { width: 44px; height: 44px; border-radius: 12px; }
.bieu-do svg { width: 100%; height: auto; display: block; }
.cau-hoi-qt { border: 1px dashed var(--vien); border-radius: 12px; padding: 12px; margin: 10px 0; }
.ngay-tuan { display: flex; gap: 6px; flex-wrap: wrap; }
.ngay-tuan label { margin: 0; font-weight: 500; display: flex; align-items: center; gap: 4px; padding: 6px 10px; border: 1px solid var(--vien); border-radius: 10px; }
.ngay-tuan input { width: 16px; height: 16px; min-height: 0; accent-color: var(--chinh); }
.trong { text-align: center; color: var(--phu); padding: 28px 12px; }
hr { border: 0; border-top: 1px solid var(--vien); margin: 16px 0; }
@media (max-width: 380px) { .luoi3 { grid-template-columns: 1fr 1fr; } }