/* =========================================================================
   Hệ thống giao diện.

   Hướng thiết kế: tươi trẻ, bo tròn, nền kem ấm. Người dùng chính là học sinh
   trung học nên tránh vẻ nghiêm trọng của phần mềm văn phòng.

   Hai sản phẩm dùng chung bố cục nhưng khác màu nhấn:
     - Hệ thống 1, trợ giảng   : màu san hô
     - Hệ thống 2, kỳ thi      : màu xanh mint
   Chỉ có một bộ màu sáng, không làm chế độ tối.
   Đặt data-he-thong="1" hoặc "2" trên thẻ body để đổi.
   ========================================================================= */

@import url('https://fonts.googleapis.com/css2?family=Nunito:ital,wght@0,400;0,600;0,700;0,800;1,400&display=swap');

:root {
  /* nền và chữ, tông ấm */
  --kem:      #fff8f3;
  --kem-dam:  #ffeee4;
  --the:      #ffffff;
  --the-mo:   #fffaf6;
  --chu:      #2e2735;
  --chu-vua:  #6b6175;
  --chu-mo:   #a89fb0;
  --vien:     #f2e4da;
  --vien-dam: #e6d3c6;

  /* san hô, hệ thống 1 */
  --san-ho-50:  #fff0ed;
  --san-ho-100: #ffdcd5;
  --san-ho:     #ff6f5e;
  --san-ho-dam: #ec4c3a;
  --san-ho-sau: #b8321f;

  /* mint, hệ thống 2 */
  --mint-50:  #e8fbf7;
  --mint-100: #c4f3e9;
  --mint:     #14c4a8;
  --mint-dam: #0ea08a;
  --mint-sau: #07705f;

  /* phụ trợ */
  --nang-50: #fff6e0;
  --nang:    #ffc44d;
  --nang-sau:#9a6400;
  --tim:     #9b7ede;
  --do:      #f4563f;
  --do-50:   #fff0ed;
  --do-sau:  #b8321f;

  /* màu nhấn, mặc định san hô, đổi theo hệ thống */
  --nhan-50:  var(--san-ho-50);
  --nhan-100: var(--san-ho-100);
  --nhan:     var(--san-ho);
  --nhan-dam: var(--san-ho-dam);
  --nhan-sau: var(--san-ho-sau);

  /* bóng đổ ấm, không dùng xám */
  --bong-1: 0 2px 6px rgba(186, 120, 95, .07);
  --bong-2: 0 4px 14px rgba(186, 120, 95, .10);
  --bong-3: 0 10px 34px rgba(186, 120, 95, .16);

  --r-nho:  14px;
  --r-vua:  20px;
  --r-lon:  28px;
  --r-tron: 999px;

  --nhanh: .15s cubic-bezier(.34, 1.3, .64, 1);
  --vua:   .3s  cubic-bezier(.34, 1.3, .64, 1);
}

body[data-he-thong="2"] {
  --nhan-50:  var(--mint-50);
  --nhan-100: var(--mint-100);
  --nhan:     var(--mint);
  --nhan-dam: var(--mint-dam);
  --nhan-sau: var(--mint-sau);
}

* { box-sizing: border-box; }

/* Hệ thống chỉ dùng một bộ màu sáng. Khai báo color-scheme để trình duyệt
   không tự đổi ô nhập, thanh cuộn và menu sang tông tối khi máy của người
   dùng đang bật chế độ tối. */
html { scroll-behavior: smooth; color-scheme: light; }

body {
  margin: 0;
  font-family: Nunito, system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--kem);
  color: var(--chu);
  line-height: 1.65;
  font-size: 16.5px;
  font-weight: 500;
  -webkit-font-smoothing: antialiased;
}

/* vệt màu mềm ở đầu trang cho đỡ phẳng */
body::before {
  content: ""; position: fixed; inset: 0 0 auto; height: 380px; z-index: -1;
  background:
    radial-gradient(760px 300px at 12% -8%, var(--nhan-50), transparent 68%),
    radial-gradient(620px 260px at 88% -14%, var(--nang-50), transparent 66%);
  pointer-events: none;
}

.khung { max-width: 1040px; margin: 0 auto; padding: 26px 18px 84px; }
.khung-hep { max-width: 620px; }

h1, h2, h3 { line-height: 1.26; letter-spacing: -.015em; font-weight: 800; margin: 0; }

/* ------------------------------------------------------- thanh điều hướng */
header.dinh { position: sticky; top: 0; z-index: 60; background: transparent; }
header.dinh .trong {
  max-width: 1040px; margin: 10px auto 0; padding: 12px 18px;
  display: flex; align-items: center; justify-content: space-between; gap: 14px;
  background: color-mix(in srgb, var(--the) 82%, transparent);
  backdrop-filter: blur(14px) saturate(1.5);
  border: 1.5px solid var(--vien);
  border-radius: var(--r-lon);
  box-shadow: var(--bong-1);
}
header.dinh h1 { font-size: 18.5px; }
header.dinh .logo-dau {
  width: 40px; height: 40px; border-radius: 13px; flex: 0 0 auto;
  display: grid; place-items: center; color: #fff;
  background: linear-gradient(140deg, var(--nhan), var(--nang));
  box-shadow: var(--bong-1);
}
header.dinh .logo-dau svg { width: 22px; height: 22px; stroke-width: 2.2; }
header.dinh .phu {
  font-size: 12.8px; font-weight: 600; color: var(--chu-mo);
  display: block; letter-spacing: 0;
}
header.dinh a {
  color: var(--chu-vua); text-decoration: none; font-size: 14.5px; font-weight: 700;
  padding: 7px 13px; border-radius: var(--r-tron); transition: var(--nhanh);
}
header.dinh a:hover { background: var(--nhan-50); color: var(--nhan-sau); }

.nguoi { display: flex; align-items: center; gap: 10px; font-size: 14.5px; font-weight: 700; }
.anh-dai-dien {
  width: 38px; height: 38px; border-radius: var(--r-tron); flex: 0 0 auto;
  background: linear-gradient(140deg, var(--nhan), var(--nang));
  color: #fff; display: grid; place-items: center;
  font-weight: 800; font-size: 15px; box-shadow: var(--bong-1);
}

/* thanh tab */
.tab-phu { position: sticky; top: 76px; z-index: 55; }
.tab-phu .trong {
  max-width: 1040px; margin: 10px auto 0; padding: 6px;
  display: flex; gap: 4px; overflow-x: auto; scrollbar-width: none;
  background: color-mix(in srgb, var(--the) 82%, transparent);
  backdrop-filter: blur(14px); border: 1.5px solid var(--vien);
  border-radius: var(--r-tron); box-shadow: var(--bong-1);
}
.tab-phu .trong::-webkit-scrollbar { display: none; }
.tab-phu a {
  padding: 9px 17px; font-size: 14.5px; font-weight: 700; white-space: nowrap;
  color: var(--chu-vua); text-decoration: none;
  border-radius: var(--r-tron); transition: var(--nhanh);
}
.tab-phu a:hover { background: var(--nhan-50); color: var(--nhan-sau); }
.tab-phu a.dang-o {
  background: var(--nhan); color: #fff;
  box-shadow: 0 4px 12px color-mix(in srgb, var(--nhan) 38%, transparent);
}

/* ------------------------------------------------------------------- thẻ */
.the {
  background: var(--the); border: 1.5px solid var(--vien);
  border-radius: var(--r-lon); padding: 26px; margin-bottom: 18px;
  box-shadow: var(--bong-1);
  animation: bat-len .4s cubic-bezier(.34, 1.3, .64, 1) both;
}
@keyframes bat-len { from { opacity: 0; transform: translateY(14px) scale(.985); } }

.the.phang { box-shadow: none; background: transparent; border-style: dashed; }
.the.gon { padding: 18px; border-radius: var(--r-vua); }
.the h2 { font-size: 22px; margin-bottom: 7px; }
.the h3 { font-size: 17.5px; margin: 22px 0 9px; }
.mo { color: var(--chu-vua); font-size: 14.8px; font-weight: 500; margin: 0 0 15px; }
.mo-nho { color: var(--chu-mo); font-size: 13.4px; font-weight: 600; }

.the-bam {
  text-decoration: none; color: inherit; display: block; position: relative;
  overflow: hidden;
  transition: transform var(--vua), box-shadow var(--vua), border-color var(--vua);
}
.the-bam::after {
  content: ""; position: absolute; inset: auto -40% -70% auto;
  width: 190px; height: 190px; border-radius: 50%;
  background: var(--nhan-50); opacity: 0; transition: opacity var(--vua);
}
.the-bam:hover {
  transform: translateY(-5px) rotate(-.35deg);
  box-shadow: var(--bong-3); border-color: var(--nhan-100);
}
.the-bam:hover::after { opacity: 1; }
.the-bam > * { position: relative; z-index: 1; }

/* ----------------------------------------------------------------- lưới */
.luoi { display: grid; gap: 17px; }
.luoi-2 { grid-template-columns: repeat(auto-fit, minmax(282px, 1fr)); }
.luoi-3 { grid-template-columns: repeat(auto-fit, minmax(186px, 1fr)); }
.luoi-4 { grid-template-columns: repeat(auto-fit, minmax(146px, 1fr)); }

/* ------------------------------------------------------------- biểu tượng */
.bt {
  width: 52px; height: 52px; border-radius: 18px; display: grid; place-items: center;
  background: var(--nhan-50); color: var(--nhan-dam); margin-bottom: 14px;
  transition: transform var(--vua);
}
.bt svg { width: 26px; height: 26px; stroke-width: 2.1; }
.the-bam:hover .bt { transform: rotate(-7deg) scale(1.07); }
svg { fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; }

/* --------------------------------------------------------------- nút bấm */
button, .nut {
  font: inherit; font-weight: 800; font-size: 15.3px; cursor: pointer;
  border: none; border-radius: var(--r-tron); padding: 12px 24px;
  background: var(--nhan); color: #fff;
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  text-decoration: none; white-space: nowrap;
  box-shadow: 0 4px 0 0 var(--nhan-dam);
  transition: transform var(--nhanh), box-shadow var(--nhanh), background var(--nhanh);
}
button:hover, .nut:hover {
  transform: translateY(-2px); box-shadow: 0 6px 0 0 var(--nhan-dam);
}
button:active, .nut:active { transform: translateY(2px); box-shadow: 0 2px 0 0 var(--nhan-dam); }
button:focus-visible, .nut:focus-visible,
input:focus-visible, select:focus-visible, textarea:focus-visible {
  outline: 3px solid var(--nhan); outline-offset: 3px;
}
button:disabled { opacity: .45; cursor: not-allowed; transform: none; }

button.phu, .nut.phu {
  background: var(--the); color: var(--chu);
  border: 2px solid var(--vien-dam); box-shadow: 0 3px 0 0 var(--vien-dam);
}
button.phu:hover, .nut.phu:hover {
  background: var(--nhan-50); border-color: var(--nhan-100);
  color: var(--nhan-sau); box-shadow: 0 5px 0 0 var(--nhan-100);
}
button.nhe { background: transparent; color: var(--chu-vua); box-shadow: none; }
button.nhe:hover { background: var(--kem-dam); color: var(--chu); box-shadow: none;
  transform: none; }
button.nguy { background: var(--do); box-shadow: 0 4px 0 0 var(--do-sau); }
button.nguy:hover { box-shadow: 0 6px 0 0 var(--do-sau); }
button.nho, .nut.nho { padding: 8px 16px; font-size: 13.8px; }
button.rong { width: 100%; }

/* --------------------------------------------------------------- ô nhập */
label { display: block; font-weight: 800; font-size: 13.8px; margin-bottom: 7px;
        color: var(--chu-vua); }
input, select, textarea {
  font: inherit; font-weight: 600; width: 100%; color: var(--chu);
  padding: 13px 17px; border: 2px solid var(--vien-dam);
  border-radius: var(--r-vua); background: var(--the);
  transition: border-color var(--nhanh), box-shadow var(--nhanh);
}
input::placeholder, textarea::placeholder { color: var(--chu-mo); font-weight: 500; }
input:focus, select:focus, textarea:focus {
  outline: none; border-color: var(--nhan);
  box-shadow: 0 0 0 4px var(--nhan-50);
}
textarea { resize: vertical; min-height: 84px; }
input[type="file"] { padding: 11px; cursor: pointer; font-weight: 600; }

.hang { display: flex; gap: 12px; flex-wrap: wrap; align-items: flex-end; }
.hang > .o { flex: 1 1 190px; min-width: 0; }
.hang > button, .hang > .nut { flex: 0 0 auto; }

/* ------------------------------------------------------------ hội thoại */
.hoi-thoai {
  display: flex; flex-direction: column; gap: 14px;
  min-height: 210px; max-height: 56vh; overflow-y: auto; padding: 4px 2px 10px;
}
.bong-chat {
  max-width: 85%; padding: 15px 19px; white-space: pre-wrap; word-break: break-word;
  font-size: 15.6px; font-weight: 500; line-height: 1.6;
  animation: noi-len .35s cubic-bezier(.34, 1.3, .64, 1) both;
}
@keyframes noi-len { from { opacity: 0; transform: translateY(14px) scale(.96); } }
.bong-chat.em {
  align-self: flex-end; background: var(--nhan); color: #fff;
  border-radius: 24px 24px 7px 24px;
  box-shadow: 0 4px 14px color-mix(in srgb, var(--nhan) 32%, transparent);
}
.bong-chat.may {
  align-self: flex-start; background: var(--kem-dam); color: var(--chu);
  border-radius: 24px 24px 24px 7px;
}
.bong-chat.loi {
  align-self: flex-start; background: var(--do-50); color: var(--do-sau);
  border: 2px solid var(--do); border-radius: 24px 24px 24px 7px;
}

.dang-go { display: inline-flex; gap: 6px; padding: 17px 21px; align-items: center; }
.dang-go i {
  width: 9px; height: 9px; border-radius: 50%; background: var(--nhan);
  display: block; animation: nhay 1.3s infinite ease-in-out;
}
.dang-go i:nth-child(2) { animation-delay: .17s; }
.dang-go i:nth-child(3) { animation-delay: .34s; }
@keyframes nhay {
  0%, 62%, 100% { transform: translateY(0) scale(.82); opacity: .35; }
  31% { transform: translateY(-9px) scale(1); opacity: 1; }
}

/* ------------------------------------------------------------- huy hiệu */
.nhan {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 5px 14px; border-radius: var(--r-tron);
  font-size: 12.8px; font-weight: 800; line-height: 1.5;
  background: var(--nhan-50); color: var(--nhan-sau);
}
.nhan.luc { background: var(--mint-50); color: var(--mint-sau); }
.nhan.cam { background: var(--nang-50); color: var(--nang-sau); }
.nhan.do  { background: var(--do-50);   color: var(--do-sau); }
.nhan.xam { background: var(--kem-dam); color: var(--chu-vua); }

.chuoi {
  display: flex; align-items: center; gap: 17px;
  background: linear-gradient(128deg, #ffd980, var(--nang));
  border-radius: var(--r-lon); padding: 18px 24px; color: #6b4200;
  font-weight: 800; box-shadow: 0 6px 20px rgba(255, 196, 77, .36);
}
.chuoi .so { font-size: 38px; line-height: 1; font-weight: 800; }

/* -------------------------------------------------------------- số liệu */
.o-so {
  text-align: center; padding: 22px 14px; background: var(--the);
  border: 1.5px solid var(--vien); border-radius: var(--r-vua);
  transition: transform var(--vua), box-shadow var(--vua);
}
.o-so:hover { transform: translateY(-4px) rotate(.5deg); box-shadow: var(--bong-2); }
.o-so .so { font-size: 36px; font-weight: 800; line-height: 1.1; color: var(--nhan-dam); }
.o-so .ten { font-size: 13px; color: var(--chu-vua); margin-top: 6px; font-weight: 700; }

/* ----------------------------------------------------------- thanh ngang */
.thanh { background: var(--kem-dam); border-radius: var(--r-tron); height: 13px;
         overflow: hidden; }
.thanh > i {
  display: block; height: 100%; border-radius: var(--r-tron);
  background: linear-gradient(90deg, var(--nhan), var(--nang));
  transition: width .8s cubic-bezier(.34, 1.2, .64, 1);
}
.thanh.luc > i { background: linear-gradient(90deg, var(--mint), #7ee8d4); }
.thanh.cam > i { background: linear-gradient(90deg, var(--nang), #ffe08a); }

/* ---------------------------------------------------------------- bảng */
.cuon-ngang { overflow-x: auto; border-radius: var(--r-vua); }
table { width: 100%; border-collapse: collapse; font-size: 14.5px; font-weight: 600; }
th, td { padding: 13px 15px; text-align: left; border-bottom: 1.5px solid var(--vien); }
th {
  font-weight: 800; color: var(--chu-vua); font-size: 12.4px;
  text-transform: uppercase; letter-spacing: .5px;
  background: var(--the-mo); position: sticky; top: 0;
}
th:first-child { border-top-left-radius: var(--r-vua); }
th:last-child  { border-top-right-radius: var(--r-vua); }
tbody tr { transition: background var(--nhanh); }
tbody tr:hover { background: var(--nhan-50); }
tbody tr:last-child td { border-bottom: none; }
td.giua, th.giua { text-align: center; }
td.phai, th.phai { text-align: right; font-variant-numeric: tabular-nums; }
td.hep { white-space: nowrap; }
.cat-dong {
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
  overflow: hidden; max-width: 330px; line-height: 1.5;
}

/* --------------------------------------------------------------- camera */
.khung-camera {
  position: relative; border-radius: var(--r-lon); overflow: hidden;
  background: #1b1622; aspect-ratio: 4 / 3; box-shadow: var(--bong-2);
  border: 3px solid var(--the);
}
.khung-camera video {
  position: absolute; inset: 0; width: 100%; height: 100%;
  object-fit: cover; transform: scaleX(-1);
}
.den-bao {
  position: absolute; top: 12px; left: 12px; right: 12px; z-index: 3;
  display: flex; align-items: center; gap: 9px;
  background: rgba(27, 22, 34, .74); backdrop-filter: blur(10px); color: #fff;
  padding: 9px 15px; border-radius: var(--r-tron);
  font-size: 13.4px; font-weight: 800; transition: background var(--vua);
}
.den-bao .cham {
  width: 10px; height: 10px; border-radius: 50%; background: var(--mint);
  flex: 0 0 auto; animation: toa 2.4s infinite;
}
@keyframes toa {
  0%   { box-shadow: 0 0 0 0 rgba(20, 196, 168, .6); }
  70%  { box-shadow: 0 0 0 11px rgba(20, 196, 168, 0); }
  100% { box-shadow: 0 0 0 0 rgba(20, 196, 168, 0); }
}
.den-bao.canh-bao { background: rgba(236, 76, 58, .9); }
.den-bao.canh-bao .cham { background: #ffd980; animation: dap 1s infinite; }
@keyframes dap { 50% { opacity: .25; } }

/* ------------------------------------------------------------ câu hỏi thi */
.cau {
  padding: 22px; border: 2px solid var(--vien); border-radius: var(--r-lon);
  background: var(--the); margin-bottom: 15px;
  transition: border-color var(--nhanh), transform var(--nhanh);
}
.cau.da-lam { border-color: var(--mint-100); background: var(--mint-50); }
.cau .de { font-weight: 800; margin-bottom: 15px; font-size: 16px; }
.cau .so-cau {
  display: inline-grid; place-items: center; width: 30px; height: 30px;
  border-radius: var(--r-tron); background: var(--nhan); color: #fff;
  font-size: 13.4px; font-weight: 800; margin-right: 10px;
}
.cau.da-lam .so-cau { background: var(--mint); }
.pa {
  display: flex; align-items: flex-start; gap: 11px;
  padding: 13px 17px; border: 2px solid var(--vien);
  border-radius: var(--r-vua); margin-bottom: 9px; cursor: pointer;
  background: var(--the); transition: var(--nhanh); font-weight: 600;
}
.pa:hover { border-color: var(--nhan-100); transform: translateX(3px); }
.pa.chon { border-color: var(--nhan); background: var(--nhan-50); font-weight: 800; }
.pa input { width: auto; margin: 4px 0 0; flex: 0 0 auto; accent-color: var(--nhan); }

.dong-ho { font-size: 27px; font-weight: 800; font-variant-numeric: tabular-nums; }
.dong-ho.gap { color: var(--do); animation: dap 1s infinite; }

.luoi-cau { display: flex; flex-wrap: wrap; gap: 7px; }
.luoi-cau button {
  width: 40px; height: 40px; padding: 0; font-size: 14px; border-radius: 13px;
  background: var(--the); color: var(--chu-vua); border: 2px solid var(--vien);
  box-shadow: none;
}
.luoi-cau button:hover { border-color: var(--nhan); color: var(--nhan-sau);
  background: var(--nhan-50); transform: translateY(-2px); box-shadow: none; }
.luoi-cau button.xong { background: var(--mint); color: #fff; border-color: var(--mint); }

/* ---------------------------------------------------------- trạng thái */
.trong-rong { text-align: center; padding: 48px 22px; color: var(--chu-vua); }
.trong-rong .hinh {
  width: 76px; height: 76px; margin: 0 auto 18px; border-radius: 26px;
  background: var(--nhan-50); color: var(--nhan-dam);
  display: grid; place-items: center;
  animation: lac 3.4s ease-in-out infinite;
}
.trong-rong .hinh svg { width: 36px; height: 36px; stroke-width: 2; }
@keyframes lac { 0%, 100% { transform: rotate(-5deg); } 50% { transform: rotate(5deg); } }

.khung-xuong > i {
  display: block; height: 15px; border-radius: var(--r-tron); margin-bottom: 11px;
  background: linear-gradient(90deg, var(--kem-dam) 25%, var(--the-mo) 50%, var(--kem-dam) 75%);
  background-size: 200% 100%; animation: truot 1.4s infinite;
}
@keyframes truot { to { background-position: -200% 0; } }

.canh-bao-o {
  background: var(--nang-50); border: 2px solid var(--nang); color: var(--nang-sau);
  padding: 16px 19px; border-radius: var(--r-vua); font-size: 14.6px; font-weight: 600;
}
.canh-bao-o.luc { background: var(--mint-50); border-color: var(--mint); color: var(--mint-sau); }
.canh-bao-o.tim { background: var(--nhan-50); border-color: var(--nhan); color: var(--nhan-sau); }

/* ------------------------------------------------------------ thông báo */
#khay-thong-bao {
  position: fixed; right: 18px; bottom: 18px; z-index: 200;
  display: flex; flex-direction: column; gap: 10px; max-width: 350px;
}
.thong-bao {
  background: var(--the); border: 2px solid var(--vien);
  border-radius: var(--r-vua); padding: 14px 18px; box-shadow: var(--bong-3);
  font-size: 14.6px; font-weight: 700;
  animation: truot-vao .34s cubic-bezier(.34, 1.3, .64, 1) both;
}
@keyframes truot-vao { from { opacity: 0; transform: translateX(34px) scale(.94); } }
.thong-bao.loi  { border-color: var(--do);   background: var(--do-50);   color: var(--do-sau); }
.thong-bao.xong { border-color: var(--mint); background: var(--mint-50); color: var(--mint-sau); }

/* ----------------------------------------------------------------- lớp phủ */
.lop-phu {
  position: fixed; inset: 0; background: rgba(46, 39, 53, .52);
  backdrop-filter: blur(5px); z-index: 150;
  display: flex; align-items: center; justify-content: center; padding: 22px;
  animation: mo-dan .22s ease both;
}
@keyframes mo-dan { from { opacity: 0; } }
.lop-phu .the {
  margin: 0; max-width: 500px; width: 100%; max-height: 86vh;
  overflow: auto; position: relative;
  animation: bung .34s cubic-bezier(.34, 1.4, .64, 1) both;
}
@keyframes bung { from { opacity: 0; transform: scale(.9) translateY(18px); } }
.lop-phu .the > .hang:last-child {
  position: sticky; bottom: -26px; margin-bottom: -26px;
  padding: 16px 0 26px; background: var(--the);
}

/* --------------------------------------------------------------- tiện ích */
.giua { text-align: center; }
.phai { text-align: right; }
.cach { margin-top: 20px; }
.cach-nho { margin-top: 12px; }
.an { display: none !important; }
.gon-gang { display: flex; align-items: center; justify-content: space-between; gap: 14px; }
.xep { display: flex; flex-direction: column; gap: 11px; }
.bao { display: flex; gap: 9px; flex-wrap: wrap; align-items: center; }

/* =========================================================================
   Trang giới thiệu (landing) nhận biết theo tên miền.
   Dùng chung ngôn ngữ thiết kế: nền kem, màu nhấn theo hệ thống, bo tròn.
   ========================================================================= */
.gioi-thieu { max-width: 1080px; }

.top-gon {
  display: flex; align-items: center; justify-content: space-between;
  gap: 14px; padding: 6px 2px 0; margin-bottom: 6px;
}
.logo-gon { display: flex; align-items: center; gap: 12px; font-weight: 800; font-size: 18px; }
.logo-gon .cham {
  width: 42px; height: 42px; border-radius: 14px; display: grid; place-items: center;
  color: #fff; flex: 0 0 auto;
  background: linear-gradient(140deg, var(--nhan), var(--nang)); box-shadow: var(--bong-1);
}
.logo-gon .cham svg { width: 23px; height: 23px; stroke-width: 2.2; }
.logo-gon .ten-mien { font-size: 13px; font-weight: 700; color: var(--chu-mo); display: block; }

/* ------------------------------------------------------------------- hero */
.hero {
  display: grid; grid-template-columns: 1.08fr .92fr; gap: 36px; align-items: center;
  padding: 30px 0 10px;
}
.chu-hero { animation: bat-len .5s cubic-bezier(.34, 1.3, .64, 1) both; }
.huy-hieu-lon {
  display: inline-flex; align-items: center; gap: 9px; padding: 7px 17px;
  border-radius: var(--r-tron); background: var(--nhan-50); color: var(--nhan-sau);
  font-weight: 800; font-size: 13.4px; margin-bottom: 18px;
}
.huy-hieu-lon .cham-nho {
  width: 9px; height: 9px; border-radius: 50%; background: var(--nhan);
  animation: toa 2.4s infinite;
}
.tieu-de-lon {
  font-size: clamp(30px, 4.7vw, 50px); line-height: 1.08;
  letter-spacing: -.022em; font-weight: 800;
}
.tieu-de-lon .sang {
  background: linear-gradient(120deg, var(--nhan-dam), var(--nang-sau));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.dan-hero {
  font-size: 17.5px; color: var(--chu-vua); font-weight: 500;
  margin: 18px 0 28px; max-width: 48ch; line-height: 1.6;
}
.nut-nhom { display: flex; gap: 13px; flex-wrap: wrap; }
.nut.lon { padding: 15px 30px; font-size: 16.5px; border-radius: var(--r-tron); }

.hero-hinh { position: relative; display: grid; place-items: center; min-height: 310px; }
.hero-hinh::before {
  content: ""; position: absolute; inset: 2% 0;
  background:
    radial-gradient(58% 58% at 52% 38%, var(--nhan-50), transparent 72%),
    radial-gradient(48% 48% at 72% 78%, var(--nang-50), transparent 70%);
  z-index: 0;
}
.hero-hinh .minh-hoa {
  position: relative; z-index: 1; width: 100%; max-width: 392px; height: auto;
  color: var(--nhan-dam);
  animation: trôi 6s ease-in-out infinite;
}
@keyframes trôi { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }

/* --------------------------------------------------------------- dải số liệu */
.dai-so { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 32px; }
.the-so {
  background: var(--the); border: 1.5px solid var(--vien); border-radius: var(--r-vua);
  padding: 20px 22px; box-shadow: var(--bong-1);
  transition: transform var(--vua), box-shadow var(--vua);
}
.the-so:hover { transform: translateY(-4px); box-shadow: var(--bong-2); }
.the-so .to { font-size: 29px; font-weight: 800; color: var(--nhan-dam); line-height: 1; letter-spacing: -.01em; }
.the-so .nho { font-size: 13.4px; color: var(--chu-vua); font-weight: 700; margin-top: 8px; }

/* ----------------------------------------------------------------- các bước */
.khoi { margin-top: 44px; }
.khoi > h2 { font-size: 24px; margin-bottom: 6px; }
.cac-buoc { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 18px; }
.buoc {
  background: var(--the); border: 1.5px solid var(--vien); border-radius: var(--r-lon);
  padding: 24px; box-shadow: var(--bong-1);
  transition: transform var(--vua), box-shadow var(--vua), border-color var(--vua);
}
.buoc:hover { transform: translateY(-4px); box-shadow: var(--bong-2); border-color: var(--nhan-100); }
.buoc .stt {
  width: 42px; height: 42px; border-radius: 14px; display: grid; place-items: center;
  background: var(--nhan); color: #fff; font-weight: 800; font-size: 17px;
  margin-bottom: 15px; box-shadow: 0 4px 0 0 var(--nhan-dam);
}
.buoc h3 { font-size: 17px; margin-bottom: 7px; }

.the-dang-nhap { max-width: 470px; margin: 44px auto 0; }

/* hai thẻ sản phẩm cho trang mặc định (localhost) */
.the-san-pham { display: block; text-decoration: none; color: inherit; }

@media (max-width: 820px) {
  .hero { grid-template-columns: 1fr; gap: 6px; padding-top: 18px; }
  .hero-hinh { order: -1; min-height: 210px; }
  .hero-hinh .minh-hoa { max-width: 250px; }
  .dai-so { grid-template-columns: 1fr; }
  .cac-buoc { grid-template-columns: 1fr; }
  .tieu-de-lon { font-size: clamp(27px, 8vw, 38px); }
}

@media print {
  header.dinh, .tab-phu, button, .nut { display: none !important; }
  body::before { display: none; }
  .the { box-shadow: none; border-color: #bbb; break-inside: avoid; }
  body { background: #fff; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .khung { padding: 18px 15px 64px; }
  .bong-chat { max-width: 93%; }
  header.dinh .trong { margin-top: 8px; padding: 10px 15px; border-radius: var(--r-vua); }
  header.dinh h1 { font-size: 16.5px; }
  header.dinh .logo-dau { width: 34px; height: 34px; border-radius: 11px; }
  header.dinh .logo-dau svg { width: 19px; height: 19px; }
  .tab-phu { top: 72px; }
  .the { padding: 20px; border-radius: var(--r-vua); }
  .hang > .o { flex-basis: 100%; }
  .hang > button { width: 100%; }
  .chuoi .so { font-size: 32px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important; animation-iteration-count: 1 !important;
    transition-duration: .01ms !important; scroll-behavior: auto !important;
  }
}