/* Phần học (/hoc/ + /hoc/bai-N/). Chỉ dùng biến của site.css. Son chỉ đánh dấu hào động. */

/* ---------- mục lục /hoc/ ---------- */
.ml-phan .dau-khu .nhan::before { content: none; }
.ml-phan .dau-khu .nhan { gap: 0; }
.ds-bai { list-style: none; margin: 0; padding: 0; }
.ds-bai li { border-bottom: 1px solid var(--ke); }
.ds-bai li:last-child { border-bottom: 0; }
.ds-bai a { display: grid; grid-template-columns: 52px 1fr; gap: 2px 10px; padding: 12px 0; color: var(--muc); text-decoration: none; }
.ds-bai a:hover .ds-bai__ten { color: var(--luc); }
.ds-bai__so { grid-row: span 2; font-family: var(--mono); font-size: 12.5px; color: var(--luc); padding-top: 3px; }
.ds-bai__ten { font-weight: 600; line-height: 1.45; }
.ds-bai__chu { font-size: 14px; line-height: 1.55; color: var(--phu); }
.hoc-bao { margin: 0; padding: 14px 16px; background: var(--nhan-nen); border: 1px solid var(--nhan-vien); border-radius: var(--bo); }

/* ---------- trang bài ---------- */
.bai { max-width: 760px; padding-top: 24px; padding-bottom: 56px; }
.bai > * + * { margin-top: 36px; }
.bai-dau .nhan { margin: 0 0 10px; }
.bai-dau .nhan a { color: var(--phu); }
.bai-dau h1 { margin: 0; font-size: 28px; font-weight: 600; line-height: 1.22; letter-spacing: -.01em; text-wrap: balance; }
.bai-dau__chu { margin: 10px 0 0; font-size: 15.5px; line-height: 1.6; color: var(--phu); }
@media (min-width: 960px) {
  .bai { padding-top: 48px; }
  .bai-dau h1 { font-size: 40px; letter-spacing: -.015em; }
  .bai-dau__chu { font-size: 17px; }
}

.bai p { margin: 0; }
.doan > p + p { margin-top: 12px; }
.doan p { font-size: 16px; line-height: 1.75; text-align: justify; } /* thân bài: canh đều, KHÔNG text-wrap: pretty (Safari iOS cân lại mọi dòng → lề phải lởm chởm) */
@media (min-width: 960px) { .doan p { font-size: 17px; } }

/* hộp: mở bài, món tương tác */
.hop { background: var(--the); border: 1px solid var(--ke); border-radius: var(--bo); padding: 18px 16px; }
.hop > * + * { margin-top: 14px; }
.hop--tt { border-color: var(--nhan-vien); }
.hop__nhan { margin: 0; display: flex; align-items: center; gap: 8px; }
.hop__nhan::after { content: ""; flex: 1; height: 1px; background: var(--ke); }
.hop--tt .hop__nhan { color: var(--luc-dam); }
@media (min-width: 720px) { .hop { padding: 22px 24px; } }

.cau-dan { font-size: 17px; font-weight: 600; line-height: 1.55; }
.giai { border-top: 1px dashed var(--ke); padding-top: 14px; }
.giai[hidden], .bai [hidden] { display: none !important; }
.giai > * + * { margin-top: 10px; }

/* nút trong bài: dùng .nut của site.css; nút chọn đáp án */
.bai .nut { align-self: flex-start; }
.chon-ds { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 170px), 1fr)); gap: 8px; }
.chon-ds--hang { display: flex; flex-wrap: wrap; }
.chon {
  min-height: 44px; padding: 10px 14px;
  font: inherit; font-size: 15px; line-height: 1.4; text-align: left; color: var(--muc);
  background: var(--giay); border: 1px solid var(--ke); border-radius: var(--bo); cursor: pointer;
}
.chon:hover:not(:disabled) { border-color: var(--luc); }
.chon:disabled { cursor: default; }
.chon.dang { border-color: var(--luc); background: var(--nhan-nen); color: var(--luc-dam); }
.chon.dung { border-color: var(--luc); background: var(--nhan-nen); color: var(--luc-dam); font-weight: 600; }
.chon.sai { border: 1px dashed var(--muc); color: var(--phu); text-decoration: line-through; text-decoration-color: var(--mo); }
.chon .hq { display: inline-block; vertical-align: middle; margin-right: 6px; }

.phan-hoi { padding: 10px 12px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); font-size: 15px; line-height: 1.6; }
.phan-hoi.dung { border-color: var(--luc); background: var(--nhan-nen); }
.phan-hoi.sai { border-style: dashed; border-color: var(--muc); }
.phan-hoi > * + * { margin-top: 6px; }

/* ô video giữ chỗ */
.video { display: grid; place-items: center; gap: 6px; aspect-ratio: 16 / 9; max-height: 360px; width: 100%;
  border: 1px dashed var(--ke); border-radius: var(--bo); background: var(--dai); text-align: center; }
.video svg { width: 40px; height: 40px; color: var(--phu); margin: 0 auto; }
.video p { font-size: 15px; font-weight: 600; color: var(--phu); }

/* mục */
.muc > * + * { margin-top: 12px; }
.muc__so { font-family: var(--mono); font-size: 12.5px; color: var(--luc); }
.muc h2 { font-size: 21px; text-wrap: balance; }
@media (min-width: 960px) { .muc h2 { font-size: 24px; } }

.thu-thach { background: var(--nhan-nen); border: 1px solid var(--nhan-vien); border-radius: var(--bo); padding: 18px 16px; }
.thu-thach > * + * { margin-top: 10px; }
.thu-thach .nhan { color: var(--luc-dam); }
.thu-thach h2 { font-size: 19px; }
.bai-sau { border-left: 3px solid var(--luc); padding: 4px 0 4px 16px; }
.bai-sau p:not(.nhan) { margin-top: 6px; font-weight: 600; line-height: 1.6; }

.dieu-huong { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; border-top: 1px solid var(--ke); padding-top: 18px; }
.dieu-huong a { display: flex; flex-direction: column; gap: 4px; padding: 12px 14px; min-height: 44px;
  border: 1px solid var(--ke); border-radius: var(--bo); background: var(--the); color: var(--muc); text-decoration: none; line-height: 1.4; }
.dieu-huong a:hover { border-color: var(--luc); }
.dieu-huong a .nhan { color: var(--luc); }
.dieu-huong .sau { grid-column: 2; text-align: right; }
.dieu-huong .ml { grid-column: 1 / -1; flex-direction: row; justify-content: center; border: 0; background: none; }

/* ---------- hình quẻ (SVG, màu theo currentColor) ---------- */
.hq { display: block; color: var(--luc); height: auto; }
.hq--s { width: 26px; } .hq--m { width: 44px; } .hq--l { width: 76px; }
.hq .dong { fill: var(--son); }

.hinh-hang { display: grid; grid-template-columns: repeat(var(--cot, 3), 1fr); gap: 8px; }
.hinh-hang figure, .dai-hinh figure { margin: 0; display: flex; flex-direction: column; align-items: center; gap: 6px;
  padding: 10px 4px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--the); font-size: 13.5px; line-height: 1.35; text-align: center; }
.hinh-hang svg { width: 100%; max-width: 140px; height: auto; }
.hinh-hang figure span { color: var(--phu); font-size: 13px; }
.dai-hinh { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; }
.dai-hinh figure .nhan { font-size: 11px; line-height: 1.3; }
.tien-trinh { display: flex; flex-wrap: wrap; justify-content: center; align-items: flex-start; gap: 8px 2px; }
.tien-trinh figure { margin: 0; width: 72px; display: flex; flex-direction: column; align-items: center; gap: 4px; text-align: center; font-size: 13.5px; }
.tien-trinh figure .nhan { font-size: 10.5px; line-height: 1.3; }
.tien-trinh .mui { color: var(--mo); padding-top: 8px; font-family: var(--mono); }
.tien-trinh__thanh { display: flex; justify-content: space-between; border-top: 2px solid var(--nhan-vien); padding-top: 4px; }
.tien-trinh__thanh .nhan { font-size: 11px; }
.hinh-lon { display: flex; justify-content: center; flex-wrap: wrap; gap: 28px; padding: 4px 0; }
.hinh-lon figure { margin: 0; display: flex; flex-direction: column; align-items: center; gap: 8px; }
.bieu-do svg { width: 100%; height: auto; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--the); }
.bieu-do figcaption { margin-top: 8px; }
.svg-chu { font-family: var(--mono); }

/* thẻ quẻ (tên + hình) */
.que-hinh { margin: 0; display: flex; flex-direction: column; align-items: center; gap: 6px; text-align: center; }
.que-hinh strong { font-size: 15px; line-height: 1.35; }
.cap-que { display: flex; flex-wrap: wrap; gap: 14px 24px; justify-content: center; align-items: flex-end; }
.cap-que .mui { font-family: var(--mono); color: var(--phu); padding-bottom: 30px; }
.cap-que--khung { padding: 14px 10px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); }
.cap-que--khung > p { flex-basis: 100%; text-align: center; font-weight: 600; }

/* ---------- từng món ---------- */
/* dòng thời gian */
.lan + .lan { margin-top: 14px; }
.lan h3 { margin: 0 0 6px; font-family: var(--mono); font-size: 12px; font-weight: 500; color: var(--phu); letter-spacing: .04em; }
.lan__moc { display: flex; gap: 6px; overflow-x: auto; padding: 2px 2px 6px; scroll-snap-type: x proximity; }
.moc-nut { flex: 0 0 auto; width: 148px; display: flex; flex-direction: column; gap: 2px; padding: 8px 10px; text-align: left;
  font: inherit; color: var(--muc); background: var(--giay); border: 1px solid var(--ke); border-radius: var(--bo); cursor: pointer; scroll-snap-align: start; }
.moc-nut[aria-expanded="true"] { border-color: var(--luc); background: var(--nhan-nen); }
.moc-nut .nhan { font-size: 11px; }
.moc-nut b { font-size: 14px; font-weight: 600; line-height: 1.35; }

/* kệ sách */
.ke .nhan { margin: 10px 0 4px; }
.ke__tang { display: flex; flex-wrap: wrap; gap: 6px; align-items: flex-end; padding: 4px 2px; border-bottom: 3px solid var(--muc); }
.sach { writing-mode: vertical-rl; transform: rotate(180deg); height: 150px; padding: 8px 6px; font: inherit; font-size: 12.5px; line-height: 1.3; text-align: left;
  color: var(--muc); background: var(--the); border: 1px solid var(--muc); border-radius: 2px; cursor: pointer; }
.sach[aria-pressed="true"] { background: var(--luc); border-color: var(--luc); color: var(--giay); }
@media (max-width: 480px) { .sach { height: 132px; } }
.the-sach { display: grid; grid-template-columns: auto 1fr; gap: 4px 14px; margin: 0; padding: 12px 14px; font-size: 14.5px; line-height: 1.55;
  border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); }
.the-sach dt { color: var(--phu); }
.the-sach dd { margin: 0; }
.dtg { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--nhan-vien); }
.dtg li { position: relative; padding: 0 0 8px 16px; font-size: 14.5px; line-height: 1.5; }
.dtg li::before { content: ""; position: absolute; left: -4px; top: 7px; width: 7px; height: 7px; border-radius: 50%; background: var(--luc); }
.dtg b { font-family: var(--mono); font-size: 12.5px; font-weight: 500; color: var(--luc); margin-right: 6px; }

/* thử đoán */
.chuoi { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.chuoi span.o { padding: 6px 10px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); font-size: 14.5px; }
.chuoi span.o.hoi { border-style: dashed; border-color: var(--luc); color: var(--luc); font-weight: 600; }
.chuoi .mui { color: var(--mo); }

/* tìm điểm khác */
.ly-ca { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.ly-ca svg { width: 100%; height: auto; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); }
.ly-ca .khac { cursor: pointer; }
.ly-ca .khac.thay { stroke: var(--luc) !important; }
.da-thay { display: flex; flex-wrap: wrap; gap: 6px; }
.da-thay span { font-size: 13.5px; padding: 2px 10px; border: 1px solid var(--ke); border-radius: var(--bo); color: var(--phu); }
.da-thay span.on { border-color: var(--luc); background: var(--nhan-nen); color: var(--luc-dam); }
.bai input[type=range] { width: 100%; accent-color: var(--luc); min-height: 32px; }
.nac { display: flex; justify-content: space-between; }
.o-vuong { width: 100%; max-width: 300px; height: auto; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); }

/* ghép cặp */
.cap-ghep { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.cap-ghep > div { display: flex; flex-direction: column; gap: 6px; }
.cap-ghep .chon.rung { border-color: var(--muc); border-style: dashed; }

/* tách đôi + bảng 64 */
.tach { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px 14px; padding: 6px 0; }
.tach figure { margin: 0; display: flex; flex-direction: column; align-items: center; gap: 4px; font-size: 12.5px; min-width: 36px; }
.tach svg.vong { width: 64px; height: 64px; color: var(--muc); }
.b64 { display: grid; grid-template-columns: repeat(9, minmax(0, 1fr)); gap: 2px; }
.b64 > * { aspect-ratio: 1; display: flex; align-items: center; justify-content: center; min-width: 0; padding: 0; font-size: 10px;
  border: 1px solid var(--ke); border-radius: 2px; background: var(--giay); color: var(--muc); }
.b64 button { cursor: pointer; font: inherit; font-size: 9px; }
.b64 button:hover { border-color: var(--luc); }
.b64 button .hq--o { width: 64%; color: var(--mo); }
.b64 button.on { background: var(--luc); border-color: var(--luc); }
.b64 button.on .hq--o { color: var(--giay); }
.b64 button.chon-o { outline: 2px solid var(--muc); outline-offset: 1px; position: relative; z-index: 1; }
.b64 button.chon-o:not(.on) { background: var(--nhan-nen); border-color: var(--luc); }
.b64 button.chon-o:not(.on) .hq--o { color: var(--luc-dam); }
.b64 .dau { border: 0; background: none; flex-direction: column; gap: 2px; color: var(--phu); font-family: var(--mono); font-size: 9.5px; aspect-ratio: auto; }

/* ghép quẻ / máy tính quẻ */
.chon-quai .chon { display: inline-flex; align-items: center; padding: 8px 10px; }
.may-tinh { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
@media (min-width: 720px) { .may-tinh { grid-template-columns: repeat(4, minmax(0, 1fr)); } }
.may-tinh label { display: flex; flex-direction: column; gap: 4px; }
.bai select, .bai textarea {
  font: inherit; font-size: 15px; color: var(--muc); background: var(--giay);
  border: 1px solid var(--ke); border-radius: var(--bo); padding: 9px 10px; min-height: 44px; width: 100%;
}
.bai select:focus, .bai textarea:focus { outline: 2px solid var(--luc); outline-offset: 0; border-color: var(--luc); }
.phep { font-family: var(--mono); font-size: 13px; line-height: 1.8; color: var(--muc); overflow-wrap: anywhere; }

/* biển số */
.bien { align-self: center; margin: 0 auto; min-width: 210px; padding: 8px 14px; text-align: center;
  font-family: var(--mono); font-size: 26px; font-weight: 500; letter-spacing: .04em; border: 2px solid var(--muc); border-radius: 4px; background: var(--the); }

/* ca mẫu */
.nut-que { padding: 12px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); cursor: pointer; font: inherit; color: var(--muc); }
.nut-que:hover:not(:disabled) { border-color: var(--luc); }
.nut-que.dung { border-color: var(--luc); background: var(--nhan-nen); }
.nut-que.sai { border-style: dashed; border-color: var(--muc); }

/* nhật ký */
.nk label { display: flex; flex-direction: column; gap: 4px; }
.nk label + label { margin-top: 10px; }
.nk textarea { resize: vertical; min-height: 64px; line-height: 1.55; }
.nk-ds { list-style: none; margin: 0; padding: 0; }
.nk-ds li { display: flex; align-items: center; gap: 8px; padding: 6px 0; border-bottom: 1px solid var(--ke); font-size: 14.5px; }
.nk-ds li span { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.nk-ds button { flex: none; font-family: var(--mono); font-size: 12px; padding: 6px 10px; min-height: 36px; background: none; border: 1px solid var(--ke); border-radius: var(--bo); color: var(--luc); cursor: pointer; }
.hang-nut-nho { display: flex; flex-wrap: wrap; gap: 8px; }

/* ---------- máy tính quẻ: nhập dương lịch ---------- */
.may-tinh--duong { grid-template-columns: repeat(2, minmax(0, 1fr)); }
@media (min-width: 720px) { .may-tinh--duong { grid-template-columns: repeat(2, minmax(0, 220px)); } }
.bai input[type=date], .bai input[type=time] {
  font: inherit; font-size: 15px; color: var(--muc); background: var(--giay);
  border: 1px solid var(--ke); border-radius: var(--bo); padding: 9px 10px; min-height: 44px; width: 100%;
}
.bai input[type=date]:focus, .bai input[type=time]:focus { outline: 2px solid var(--luc); outline-offset: 0; border-color: var(--luc); }
.am-lich { padding: 10px 12px; font-size: 15px; line-height: 1.6; color: var(--luc-dam);
  background: var(--nhan-nen); border: 1px solid var(--nhan-vien); border-radius: var(--bo); }

/* ---------- nâng giao diện (theo bản mẫu lô bài): giấy kẻ ô, đầu bài rõ, thẻ bài sau ---------- */
/* hộp mở bài + món tương tác: nền giấy kẻ ô kiểu bản vẽ kỹ thuật */
.hop {
  background:
    linear-gradient(var(--dai) 1px, transparent 1px) 0 0 / 24px 24px,
    linear-gradient(90deg, var(--dai) 1px, transparent 1px) 0 0 / 24px 24px,
    var(--the);
}
.hop--tt { border-color: var(--luc); }

/* đầu bài */
.bai-dau__so { margin: 18px 0 6px; font-family: var(--mono); font-size: 14px; font-weight: 500; color: var(--luc); }
.bai-dau__so span { color: var(--mo); }
.bai-dau h1 { font-size: 32px; line-height: 1.15; }
@media (min-width: 960px) { .bai-dau h1 { font-size: 46px; } }
.tien-do { list-style: none; margin: 22px 0 0; padding: 0; display: flex; gap: 3px; }
.tien-do li { flex: 1; }
.tien-do a { display: block; padding: 8px 0; }
.tien-do a::before { content: ""; display: block; height: 4px; border-radius: 2px; background: var(--ke); }
.tien-do a.qua::before { background: var(--nhan-vien); }
.tien-do a.dang::before { background: var(--luc); height: 6px; margin-top: -1px; }
.tien-do a:hover::before { background: var(--luc); }

/* số mục: nhãn mono + vạch mảnh */
.muc__so { display: flex; align-items: center; gap: 10px; font-weight: 500; }
.muc__so::after { content: ""; flex: 0 0 40px; height: 1px; background: var(--nhan-vien); }

/* thử thách */
.thu-thach { border-left: 3px solid var(--luc); }

/* thẻ bài sau: cả thẻ bấm được */
a.bai-sau, section.bai-sau { display: block; padding: 18px 18px 16px; border: 1px solid var(--muc); border-radius: var(--bo);
  background: var(--the); color: var(--muc); text-decoration: none; }
a.bai-sau:hover { border-color: var(--luc); }
a.bai-sau:hover .bai-sau__di { color: var(--luc-dam); }
.bai-sau p:not(.nhan) { font-size: 17px; }
.bai-sau__di { display: inline-block; margin-top: 12px; color: var(--luc); font-weight: 500; }

/* ---------- mục lục /hoc/: thẻ bài ---------- */
.ds-bai--the { display: grid; grid-template-columns: 1fr; gap: 10px; }
@media (min-width: 720px) { .ds-bai--the { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
.ds-bai--the li, .ds-bai--the li:last-child { border: 0; }
.ds-bai--the a { height: 100%; grid-template-columns: 1fr; gap: 4px; padding: 14px 16px 12px;
  border: 1px solid var(--ke); border-radius: var(--bo); background: var(--the); }
.ds-bai--the a:hover { border-color: var(--luc); }
.ds-bai--the .ds-bai__so { grid-row: auto; padding: 0; }
.ds-bai--the .ds-bai__ten { font-size: 17px; }
.ds-bai__mon { margin-top: 8px; padding-top: 8px; border-top: 1px dashed var(--ke); font-family: var(--mono); font-size: 12px; color: var(--luc-dam); }
.ml-phan .dau-khu__dem { margin: 6px 0 0; font-family: var(--mono); font-size: 12.5px; color: var(--phu); }
.hoc-bat-dau { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }

/* ---------- tranh bìa bài (hoc/hinh.js): nét mảnh lục bảo trên giấy kẻ ô ---------- */
.bia, .ds-bai__bia, .trang-dau__hinh {
  color: var(--luc-dam);
  background:
    linear-gradient(var(--dai) 1px, transparent 1px) 0 0 / 16px 16px,
    linear-gradient(90deg, var(--dai) 1px, transparent 1px) 0 0 / 16px 16px,
    var(--the);
  border: 1px solid var(--ke); border-radius: var(--bo);
}
.bia svg, .ds-bai__bia svg, .trang-dau__hinh svg { display: block; width: 100%; height: 100%; }
.bia { position: relative; margin: 14px 0 0; aspect-ratio: 240 / 130; padding: 10px 12px; overflow: hidden; }
.bia svg { max-width: 420px; margin: 0 auto; }
.bia__so { position: absolute; left: 14px; top: 8px; font-family: var(--mono); font-size: 44px; font-weight: 400; line-height: 1;
  color: var(--nhan-vien); letter-spacing: -.02em; }
@media (min-width: 720px) {
  .bia { aspect-ratio: auto; height: 240px; padding: 16px 24px; }
  .bia__so { font-size: 72px; left: 22px; top: 14px; }
}
.bia + .bai-dau__so { margin-top: 18px; }

/* thẻ bài ở mục lục: tranh nhỏ đầu thẻ */
.ds-bai--the .ds-bai__bia { display: block; height: 96px; margin: -14px -16px 6px; padding: 6px; border: 0; border-bottom: 1px solid var(--ke); border-radius: var(--bo) var(--bo) 0 0; }
.ds-bai--the a { overflow: hidden; }
.ds-bai--the a:hover .ds-bai__bia { color: var(--luc); }
@media (min-width: 960px) { .ds-bai--the .ds-bai__bia { height: 120px; } }

/* hình đầu trang mục lục */
.trang-dau__hinh { max-width: 360px; aspect-ratio: 240 / 150; margin-top: 22px; padding: 8px; }
.trang-dau__hinh:empty { display: none; }
@media (min-width: 960px) {
  .trang-dau .khung:has(.trang-dau__hinh) { display: grid; grid-template-columns: 1fr 380px; column-gap: 48px; }
  .trang-dau .khung:has(.trang-dau__hinh) > * { grid-column: 1; }
  .trang-dau .khung > .trang-dau__hinh { grid-column: 2; grid-row: 1 / span 5; align-self: center; max-width: none; margin: 0; }
}

/* ---------- hình minh họa thêm trong mục (bai.js HINH_THEM) ---------- */
.hinh-them { padding-top: 6px; }
.hinh-them > * + * { margin-top: 8px; }
.hinh-them .nhan { text-align: center; }
.hai-cap { display: grid; gap: 10px; }
@media (min-width: 640px) { .hai-cap { grid-template-columns: 1fr 1fr; } }
.hai-cap .cap-que { gap: 10px 16px; }
.chong { display: flex; flex-direction: column; gap: 9px; }

/* các bước nối nhau */
.buoc { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; counter-reset: b; }
.buoc li { position: relative; display: flex; flex-direction: column; gap: 2px; padding: 12px 14px 12px 52px;
  border: 1px solid var(--ke); border-radius: var(--bo); background: var(--the); line-height: 1.45; }
.buoc li b { font-weight: 600; }
.buoc li span:not(.buoc__so) { font-size: 14.5px; color: var(--phu); }
.buoc__so { position: absolute; left: 14px; top: 13px; font-family: var(--mono); font-size: 13px; color: var(--luc); }
.buoc li + li::before { content: ""; position: absolute; left: 24px; top: -9px; height: 8px; border-left: 1px solid var(--nhan-vien); }
@media (min-width: 640px) {
  .buoc--ngang { grid-auto-flow: column; grid-auto-columns: 1fr; }
  .buoc--ngang li { padding: 12px 12px 12px; padding-top: 34px; }
  .buoc--ngang .buoc__so { top: 12px; left: 12px; }
  .buoc--ngang li + li::before { left: -9px; top: 50%; height: 0; width: 8px; border-left: 0; border-top: 1px solid var(--nhan-vien); }
}

/* rẽ nhánh: một gốc, nhiều hướng */
.re-nhanh { display: grid; gap: 10px; padding: 14px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); }
.re-nhanh__goc { justify-self: center; text-align: center; padding: 10px 18px; border: 1px solid var(--muc); border-radius: var(--bo); background: var(--dai); }
.re-nhanh__goc b { display: block; margin-top: 2px; font-size: 17px; }
.re-nhanh__ds { list-style: none; margin: 0; padding: 14px 0 0; display: grid; grid-template-columns: repeat(2, 1fr); gap: 6px;
  border-top: 1px dashed var(--nhan-vien); position: relative; }
.re-nhanh__ds::before { content: ""; position: absolute; left: 50%; top: -11px; height: 10px; border-left: 1px solid var(--nhan-vien); }
@media (min-width: 640px) { .re-nhanh__ds { grid-template-columns: repeat(4, 1fr); } }
.re-nhanh__ds li { text-align: center; padding: 8px 6px; border: 1px solid var(--luc); border-radius: var(--bo); background: var(--nhan-nen); color: var(--luc-dam); font-size: 14.5px; font-weight: 600; }

/* bảng 64 nhỏ, đường chéo quẻ Thuần */
.bang-thuan { display: grid; grid-template-columns: repeat(9, minmax(0, 1fr)); gap: 2px; max-width: 420px; margin: 0 auto; }
.bang-thuan > span { aspect-ratio: 1; display: flex; align-items: center; justify-content: center; border: 1px solid var(--ke); border-radius: 2px; background: var(--giay); }
.bang-thuan .hq { width: 58%; color: var(--ke); }
.bang-thuan .dau { border: 0; background: none; }
.bang-thuan .dau .hq { color: var(--phu); width: 50%; }
.bang-thuan .thuan { background: var(--luc); border-color: var(--luc); }
.bang-thuan .thuan .hq { color: var(--giay); }

.bieu-do--vua { max-width: 340px; margin-left: auto; margin-right: auto; text-align: center; }

/* số → tượng */
.so-tuong { display: grid; grid-template-columns: repeat(4, 1fr); gap: 6px; }
@media (min-width: 640px) { .so-tuong { grid-template-columns: repeat(8, 1fr); } }
.so-tuong .que-hinh { padding: 10px 2px 8px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--the); gap: 4px; }
.so-tuong .que-hinh strong { font-size: 14px; }
.so-tuong .que-hinh .nhan { font-size: 11px; }

/* hai tượng đơn ghép thành quẻ */
.ghep-quai { padding: 12px 10px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); }
.ghep-quai > .nhan { font-size: 20px; font-weight: 500; color: var(--luc); margin-bottom: 8px; letter-spacing: .1em; }
.ghep-quai__hang { display: flex; align-items: center; justify-content: center; gap: 14px; }
.ghep-quai__don { display: flex; flex-direction: column; gap: 10px; }
.ghep-quai__don span { display: flex; align-items: center; gap: 8px; }
.ghep-quai__don em { font-style: normal; font-size: 14px; color: var(--phu); }
.ghep-quai .mui { font-family: var(--mono); color: var(--phu); }

/* so sánh lớn nhỏ */
.so-sanh { margin: 0; padding: 12px 10px 10px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); }
.so-sanh__hang { display: flex; justify-content: center; align-items: flex-end; gap: 22px; min-height: 130px;
  background: linear-gradient(var(--muc), var(--muc)) 0 calc(100% - 25px) / 100% 1px no-repeat; }
.so-sanh__hang span { display: flex; flex-direction: column; align-items: center; gap: 6px; font-size: 13.5px; line-height: 19px; color: var(--phu); }
.so-sanh__hang i { display: block; width: 54px; border: 1px solid var(--muc); border-bottom: 0; border-radius: 3px 3px 0 0; background: var(--the); }
.so-sanh__hang .on { color: var(--luc-dam); font-weight: 600; }
.so-sanh__hang .on i { background: var(--luc); border-color: var(--luc); }
.so-sanh figcaption { margin-top: 8px; }

/* ba nhóm */
.ba-nhom { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.ba-nhom div { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 2px; aspect-ratio: 1; max-width: 150px; width: 100%; justify-self: center;
  border: 1px solid var(--luc); border-radius: 50%; background: var(--nhan-nen); text-align: center; padding: 6px; }
.ba-nhom b { font-size: 15.5px; color: var(--luc-dam); }
.ba-nhom span { font-size: 12.5px; line-height: 1.3; color: var(--phu); }

/* biến thông: một quẻ, nhiều tình huống */
.bien-thong { display: grid; gap: 12px; align-items: center; padding: 14px; border: 1px solid var(--ke); border-radius: var(--bo); background: var(--giay); }
@media (min-width: 640px) { .bien-thong { grid-template-columns: 150px 1fr; } }
.bien-thong ul { list-style: none; margin: 0; padding: 0 0 0 14px; border-left: 1px solid var(--nhan-vien); display: grid; gap: 8px; }
.bien-thong li { display: flex; flex-direction: column; gap: 1px; font-size: 15px; line-height: 1.45; }
.bien-thong li .nhan { text-align: left; color: var(--luc); }
.bang-thuan > span:first-child { border: 0; background: none; }
.chong { gap: 16px; }
.ba-nhom + .nhan { margin-top: 14px; }
.bieu-do--vua { max-width: 420px; }
.bieu-do--vua:has(svg[viewBox="0 0 320 320"]) { max-width: 340px; }