/* Bài "Cách áp nhiều mã giảm giá Shopee" (public/meo-san-sale/cach-ap-nhieu-ma-giam-gia-shopee.html).
   Nạp sau /hoi-dap/hoi-dap.css, dùng lại token màu, viền, theme của file đó.
   Ý tưởng giao diện: hoá đơn thanh toán bị trừ dần qua từng lớp mã.
   Quy tắc nút (frontend/CLAUDE.md): rê chuột chỉ đổi màu, đặt trong @media (hover: hover), không transform, không đổi bóng. */

.am { --am-mono: ui-monospace, 'SFMono-Regular', Menlo, Consolas, monospace; --am-red: var(--primary); }
.am .num, .am-receipt, .am-calc output, .am-calc input { font-variant-numeric: tabular-nums; }

/* ---------- Đầu bài: chữ bên trái, hoá đơn bên phải ---------- */
.am-hero { padding-bottom: 32px; }
.am-hero .wrap { max-width: 1040px; }
.am-hero-grid { display: grid; gap: 24px; align-items: start; }
@media (min-width: 900px) {
  .am-hero-grid { grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr); gap: 40px; }
}
.am-hero h1 em { font-style: normal; }
.am-kicker { display: inline-block; margin: 0 0 10px; font-size: 14px; font-weight: 800; letter-spacing: 0.02em; color: var(--pop-ink); }
.am-kicker b { display: inline-block; margin-right: 6px; padding: 1px 8px; border: 2px solid var(--pop-ink); border-radius: 6px; background: var(--pop-sun); }

/* Hoá đơn: giấy trắng, mép dưới răng cưa, số căn phải */
.am-receipt {
  position: relative;
  margin: 4px 6px 18px 0;
  padding: 18px 18px 22px;
  border: var(--pop-bw) solid var(--pop-edge);
  border-bottom: 0;
  border-radius: 14px 14px 0 0;
  background: var(--surface);
  box-shadow: 5px 5px 0 var(--pop-shadow-color);
  font-size: 15px;
  line-height: 1.45;
}
.am-receipt::after {
  content: '';
  position: absolute;
  left: calc(var(--pop-bw) * -1);
  right: calc(var(--pop-bw) * -1);
  bottom: -12px;
  height: 12px;
  background:
    linear-gradient(135deg, var(--surface) 6px, transparent 0) 0 0 / 12px 12px repeat-x,
    linear-gradient(225deg, var(--surface) 6px, transparent 0) 0 0 / 12px 12px repeat-x;
  border-left: var(--pop-bw) solid var(--pop-edge);
  border-right: var(--pop-bw) solid var(--pop-edge);
}
.am-receipt-head { display: flex; justify-content: space-between; gap: 8px; margin: 0 0 10px; padding-bottom: 10px; border-bottom: 2px dashed var(--border-strong); font-size: 13px; color: var(--muted); }
.am-receipt-head strong { color: var(--pop-ink); font-size: 14px; }
.am-receipt ol { margin: 0; padding: 0; list-style: none; }
.am-receipt li { display: grid; grid-template-columns: 26px minmax(0, 1fr) auto; gap: 8px; align-items: baseline; padding: 6px 0; }
.am-receipt li + li { border-top: 1px dotted var(--border-strong); }
.am-receipt .tag { display: inline-grid; place-items: center; width: 22px; height: 22px; border: 2px solid var(--pop-ink); border-radius: 50%; background: var(--pop-sun); color: var(--pop-ink); font-size: 12px; font-weight: 900; }
.am-receipt .tag--base { background: var(--surface-3); }
.am-receipt .what small { display: block; font-size: 12.5px; color: var(--muted); }
.am-receipt .amt { font-family: var(--am-mono); font-weight: 700; white-space: nowrap; }
.am-receipt .minus { color: var(--success-dark); }
.am-receipt .later { color: var(--muted); }
.am-receipt-total { display: flex; justify-content: space-between; align-items: baseline; gap: 8px; margin-top: 10px; padding-top: 10px; border-top: 2px solid var(--pop-ink); font-weight: 900; }
.am-receipt-total .amt { font-size: 22px; color: var(--am-red); }
.am-receipt-note { margin: 10px 0 0; font-size: 12.5px; color: var(--muted); }
.am-stamp {
  position: absolute;
  top: 12px;
  right: 14px;
  padding: 2px 8px;
  border: 2px solid var(--am-red);
  border-radius: 6px;
  color: var(--am-red);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  transform: rotate(-6deg);
  opacity: 0.85;
}

/* ---------- Thân bài rộng hơn một chút để bảng và máy tính thoáng ---------- */
.am-body { max-width: 800px; }

/* Ô trả lời nhanh: viền trái đỏ, chữ to */
.am-short {
  margin: 28px 0 8px;
  padding: 16px 18px;
  border-left: 6px solid var(--am-red);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  background: var(--primary-50);
}
.am-short p { margin: 0; }
.am-short p + p { margin-top: 8px; }
.am-short-label { font-size: 13px; font-weight: 900; letter-spacing: 0.06em; text-transform: uppercase; color: var(--am-red); }

/* ---------- Sơ đồ ô mã ở trang Thanh toán ---------- */
.am-slots { margin: 18px 0 8px; display: grid; gap: 10px; }
.am-slot {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 12px;
  align-items: center;
  padding: 12px 14px;
  border: var(--pop-bw) solid var(--pop-edge);
  border-radius: var(--radius-lg);
  background: var(--surface);
  margin-right: 4px;
  box-shadow: 3px 3px 0 var(--pop-shadow-color);
}
.am-slot-n { font-family: var(--am-mono); font-size: 26px; font-weight: 800; line-height: 1; color: var(--pop-ink); }
.am-slot-n small { display: block; margin-top: 2px; font-family: var(--font-sans); font-size: 11px; font-weight: 700; color: var(--muted); }
.am-slot h3 { margin: 0 0 2px; font-size: 17px; }
.am-slot p { margin: 0; font-size: 15px; color: var(--text-2); }
.am-slot .or { display: inline-block; margin: 0 4px; padding: 0 6px; border-radius: 4px; background: var(--pop-sun); color: var(--pop-ink); font-size: 12px; font-weight: 900; }
.am-slot--side { background: var(--surface-3); box-shadow: none; border-style: dashed; }
.am-slot--cb { background: var(--pop-mint); }

/* ---------- Từng lớp: số lớn bên trái, nội dung bên phải ---------- */
.am-layer { position: relative; margin: 36px 0 0; padding-left: 0; }
@media (min-width: 720px) {
  .am-layer { padding-left: 76px; }
  .am-layer::before {
    content: attr(data-n);
    position: absolute;
    left: 0;
    top: -4px;
    width: 56px;
    font-family: var(--am-mono);
    font-size: 44px;
    font-weight: 800;
    line-height: 1;
    color: transparent;
    -webkit-text-stroke: 2px var(--pop-ink);
  }
}
.am-layer h2 { margin-top: 0; }
.am-layer h2 .lv { display: inline-block; margin-right: 8px; padding: 0 8px; border: 2px solid var(--pop-ink); border-radius: 6px; background: var(--pop-sun); font-size: 0.7em; vertical-align: 0.12em; }
@media (min-width: 720px) { .am-layer h2 .lv { display: none; } }
.am-facts { display: grid; gap: 0; margin: 14px 0; border: var(--pop-bw) solid var(--pop-edge); border-radius: var(--radius-md); background: var(--surface); overflow: hidden; }
.am-facts div { display: grid; grid-template-columns: 108px minmax(0, 1fr); gap: 10px; padding: 10px 14px; font-size: 15.5px; }
.am-facts div + div { border-top: 1px solid var(--border); }
.am-facts dt { font-weight: 800; color: var(--pop-ink); }
.am-facts dd { margin: 0; color: var(--text-2); }

/* Ghi chú bên lề kiểu bút đỏ */
.am-margin-note { margin: 14px 0; padding: 10px 14px; border: 2px dashed var(--am-red); border-radius: var(--radius-md); color: var(--text-2); font-size: 15.5px; }
.am-margin-note strong { color: var(--am-red); }

/* ---------- Máy tính 4 lớp ---------- */
.am-calc {
  margin: 20px 4px 8px 0;
  border: var(--pop-bw) solid var(--pop-edge);
  border-radius: 20px;
  background: var(--surface);
  box-shadow: 5px 5px 0 var(--pop-shadow-color);
  overflow: hidden;
}
.am-calc-head { padding: 14px 18px; border-bottom: var(--pop-bw) solid var(--pop-edge); background: var(--pop-sun-soft); }
.am-calc-head p { margin: 0; }
.am-calc-head .t { font-weight: 900; color: var(--pop-ink); font-size: 18px; }
.am-calc-head .s { font-size: 14px; color: var(--text-2); }
.am-calc-grid { display: grid; }
@media (min-width: 760px) { .am-calc-grid { grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr); } }
.am-calc-form { padding: 16px 18px; display: grid; gap: 14px; }
.am-calc fieldset { margin: 0; padding: 0; border: 0; min-width: 0; }
.am-calc legend { padding: 0; margin-bottom: 6px; font-size: 14px; font-weight: 900; color: var(--pop-ink); }
.am-calc legend .tag { display: inline-grid; place-items: center; width: 20px; height: 20px; margin-right: 6px; border: 2px solid var(--pop-ink); border-radius: 50%; background: var(--pop-sun); font-size: 11px; }
.am-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(128px, 1fr)); gap: 8px; }
.am-field { display: grid; gap: 3px; }
.am-field label { font-size: 13px; font-weight: 600; color: var(--muted); }
.am-field input, .am-field select {
  width: 100%;
  min-height: 44px;
  padding: 0 12px;
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: var(--text);
  font: inherit;
  font-size: 16px;
  font-weight: 700;
}
.am-field input:focus, .am-field select:focus { outline: 2px solid var(--pop-ink); outline-offset: 1px; border-color: var(--pop-ink); background: var(--surface); }
.am-hint { margin: 2px 0 0; font-size: 12.5px; color: var(--muted); }
.am-calc-out { padding: 16px 18px 20px; border-top: var(--pop-bw) solid var(--pop-edge); background: var(--pop-paper); }
@media (min-width: 760px) { .am-calc-out { border-top: 0; border-left: var(--pop-bw) dashed var(--pop-edge); } }
.am-calc-out .am-receipt { margin: 0 0 16px; box-shadow: none; }
.am-pick { margin: 0 0 12px; padding: 10px 12px; border-radius: var(--radius-md); background: var(--success-bg); color: var(--success-dark); font-size: 15px; font-weight: 700; }
.am-pick.is-warn { background: var(--primary-50); color: var(--primary-hover); }
.am-calc-reset { padding: 0; border: 0; background: none; color: var(--muted); font: inherit; font-size: 13px; font-weight: 700; text-decoration: underline; cursor: pointer; }

/* ---------- Khối thao tác: dán link → Bo tìm mã + link hoàn tiền ---------- */
.am-go {
  margin: 28px 4px 8px 0;
  padding: 20px;
  border: 2px solid var(--pop-ink);
  border-radius: 20px;
  background: var(--primary);
  color: var(--on-primary);
  box-shadow: 5px 5px 0 var(--pop-ink);
}
.am-go-title { margin: 0 0 4px; font-size: 20px; font-weight: 900; }
.am-go p { margin: 0 0 14px; color: rgba(255, 255, 255, 0.92); font-size: 15.5px; }
.am-go form { display: grid; gap: 10px; }
@media (min-width: 600px) { .am-go form { grid-template-columns: minmax(0, 1fr) auto; } }
.am-go input {
  min-height: 50px;
  padding: 0 14px;
  border: 2px solid var(--pop-ink);
  border-radius: var(--radius-md);
  background: #fff;
  color: #1f1f1f;
  font: inherit;
  font-size: 16px;
}
.am-go input:focus { outline: 3px solid var(--pop-sun); outline-offset: 1px; }
.am-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 50px;
  padding: 0 20px;
  border: 2px solid var(--pop-ink);
  border-radius: var(--radius-md);
  background: var(--pop-sun);
  color: var(--pop-ink);
  font: inherit;
  font-size: 16px;
  font-weight: 900;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.15s ease, color 0.15s ease;
}
.am-btn .arr { display: inline-block; transition: transform 0.15s ease; }
.am-btn[disabled] { cursor: progress; opacity: 0.75; }
.am-go-msg { min-height: 1.4em; margin: 8px 0 0; font-size: 14px; font-weight: 700; color: #fff; }
.am-go-msg:empty { min-height: 0; margin: 0; }
.am-go-alt { margin: 10px 0 0; font-size: 13.5px; }
.am-go-alt a { color: #fff; font-weight: 700; }
.am-spin { width: 16px; height: 16px; border: 2.5px solid currentColor; border-right-color: transparent; border-radius: 50%; animation: am-spin 0.7s linear infinite; }
@keyframes am-spin { to { transform: rotate(360deg); } }

/* ---------- Popup đăng nhập ---------- */
.am-dialog {
  width: min(420px, calc(100vw - 32px));
  padding: 0;
  border: 2px solid var(--pop-ink);
  border-radius: 20px;
  background: var(--surface);
  color: var(--text);
  box-shadow: 6px 6px 0 var(--pop-ink);
}
.am-dialog::backdrop { background: rgba(20, 16, 15, 0.55); }
.am-dialog-body { padding: 22px 20px 18px; }
.am-dialog h2 { margin: 0 0 6px; font-size: 21px; line-height: 1.3; color: var(--pop-ink); }
.am-dialog p { margin: 0 0 14px; font-size: 15.5px; color: var(--text-2); }
.am-dialog ul { margin: 0 0 16px; padding: 0; list-style: none; display: grid; gap: 6px; font-size: 15px; }
.am-dialog li { display: grid; grid-template-columns: 22px minmax(0, 1fr); gap: 8px; }
.am-dialog li::before { content: '✓'; display: inline-grid; place-items: center; width: 20px; height: 20px; border-radius: 50%; background: var(--success-bg); color: var(--success-dark); font-size: 12px; font-weight: 900; }
.am-google {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  width: 100%;
  min-height: 50px;
  border: 2px solid var(--pop-ink);
  border-radius: var(--radius-md);
  background: #fff;
  color: #1f1f1f;
  font: inherit;
  font-size: 16px;
  font-weight: 800;
  cursor: pointer;
  transition: background-color 0.15s ease;
}
.am-google[disabled] { cursor: progress; opacity: 0.8; }
.am-dialog-links { display: grid; gap: 8px; margin-top: 12px; font-size: 14.5px; text-align: center; }
.am-dialog-links a, .am-dialog-links button { padding: 6px; border: 0; background: none; color: var(--text-2); font: inherit; font-weight: 700; text-decoration: underline; cursor: pointer; }
.am-dialog-close { position: absolute; top: 10px; right: 10px; width: 36px; height: 36px; border: 0; border-radius: 50%; background: var(--surface-3); color: var(--pop-ink); font-size: 20px; line-height: 1; cursor: pointer; }
.am-webview { margin: 0 0 12px; padding: 12px 14px; border-radius: var(--radius-md); background: var(--pop-sun-soft); font-size: 15px; color: var(--pop-ink); }
.am-webview strong { display: block; margin-bottom: 4px; }
.am-webview[hidden] { display: none; }

@media (hover: hover) {
  .am-btn:hover { background: #ffe27a; color: var(--pop-ink); }
  .am-btn:hover .arr { transform: translateX(3px); }
  .am-google:hover { background: #f4f1ee; }
  .am-dialog-close:hover { background: var(--border-strong); }
  .am-dialog-links a:hover, .am-dialog-links button:hover { color: var(--primary); }
}

@media (prefers-reduced-motion: reduce) {
  .am-btn, .am-btn .arr, .am-google { transition: none; }
  .am-spin { animation-duration: 1.6s; }
}