/* ============================================================
   Học tiếng Trung — bảng màu pastel "kem & bạc hà"
   Mặc định nền sáng dịu (không trắng chói, không đen tuyền).
   Bản tối là tuỳ chọn, đổi ở tab Tôi → Nền.
   ============================================================ */

/* MẶC ĐỊNH: tông sáng pastel — nền kem ấm, điểm nhấn bạc hà và đào.
   Bản tối vẫn giữ, đổi ở tab Tôi → Nền. */
:root {
  --nen:        #f8f5f0;   /* kem ấm, không phải trắng chói */
  --nen-2:      #ffffff;
  --nen-3:      #f1ece4;
  --vien:       #e6ded2;
  --chu:        #3b4048;   /* xám ấm, không phải đen */
  --chu-mo:     #78818c;
  --chu-rat-mo: #a3aab3;

  --ngoc:       #34886c;   /* bạc hà đậm vừa đủ để đọc chữ */
  --ngoc-mo:    #e3f2ea;   /* mảng pastel bạc hà */
  --ho-phach:   #b07c33;   /* đào/mật ong */
  --ho-phach-mo:#fbf0de;

  --dung:       #3d8f63;
  --dung-nen:   #e5f3e9;
  --sai:        #c25e48;   /* hồng đất, không đỏ chói */
  --sai-nen:    #fbe9e5;
  --tam:        #a17a22;
  --tam-nen:    #fbf1de;
  --chu-tren-ngoc: #ffffff;

  --bo-goc:     18px;
  --bo-goc-to:  24px;
  --do-bong:    0 2px 12px rgba(120, 100, 76, .10);
  --tab-cao:    64px;
  --an-toan-duoi: env(safe-area-inset-bottom, 0px);
}

/* Bản tối: bật ở tab Tôi, hoặc khi trang xuất bản đặt data-theme="dark". */
:root[data-theme="toi"], :root[data-theme="dark"] {
  --nen:        #15181d;
  --nen-2:      #1c2128;
  --nen-3:      #232931;
  --vien:       #2e3640;
  --chu:        #e9e5dd;
  --chu-mo:     #9aa4ae;
  --chu-rat-mo: #6b7681;
  --ngoc:       #5fbf9f;
  --ngoc-mo:    rgba(95, 191, 159, .14);
  --ho-phach:   #e0a458;
  --ho-phach-mo:rgba(224, 164, 88, .14);
  --dung:       #63c48d;
  --dung-nen:   rgba(99, 196, 141, .16);
  --sai:        #e08573;
  --sai-nen:    rgba(224, 133, 115, .16);
  --tam:        #dfb45f;
  --tam-nen:    rgba(223, 180, 95, .16);
  --chu-tren-ngoc: #0d1512;
  --do-bong:    0 2px 14px rgba(0,0,0,.28);
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

html, body {
  margin: 0; padding: 0;
  background: var(--nen);
  color: var(--chu);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.5;
  overscroll-behavior-y: none;
  -webkit-font-smoothing: antialiased;
}

body {
  padding-bottom: calc(var(--tab-cao) + var(--an-toan-duoi));
  min-height: 100vh;
}

/* nền có hai quầng pastel rất nhạt cho đỡ phẳng */
body::before {
  content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background:
    radial-gradient(72% 46% at 50% 0%, rgba(126, 196, 170, .20), transparent 72%),
    radial-gradient(62% 42% at 88% 100%, rgba(233, 178, 130, .16), transparent 72%);
}
:root[data-theme="toi"] body::before, :root[data-theme="dark"] body::before {
  background:
    radial-gradient(70% 45% at 50% 0%, rgba(95,191,159,.09), transparent 70%),
    radial-gradient(60% 40% at 85% 100%, rgba(224,164,88,.06), transparent 70%);
}

/* ---------------------------------------------------------- chữ Hán */
.hz {
  font-family: "PingFang SC", "Hiragino Sans GB", "Noto Sans CJK SC",
               "Microsoft YaHei", sans-serif;
  letter-spacing: .02em;
}
.py { color: var(--ngoc); font-size: .95em; letter-spacing: .01em; }
.vi { color: var(--chu-mo); }

/* ---------------------------------------------------------- khung chung */
#man-hinh { padding: 0 16px; max-width: 720px; margin: 0 auto; }

.dau-trang {
  padding: calc(env(safe-area-inset-top, 0px) + 18px) 0 6px;
  display: flex; align-items: center; gap: 12px;
}
.dau-trang h1 { font-size: 26px; margin: 0; font-weight: 640; letter-spacing: -.02em; }
.dau-trang .phu { color: var(--chu-mo); font-size: 14px; margin: 2px 0 0; }

.nut-lui {
  flex: 0 0 auto; width: 40px; height: 40px; border-radius: 50%;
  border: 1px solid var(--vien); background: var(--nen-2); color: var(--chu);
  font-size: 20px; line-height: 1; cursor: pointer;
}

.the {
  background: var(--nen-2);
  border: 1px solid var(--vien);
  border-radius: var(--bo-goc);
  padding: 16px;
  margin: 12px 0;
  box-shadow: var(--do-bong);
}

.muc-nho { font-size: 13px; letter-spacing: .08em; text-transform: uppercase; color: var(--chu-rat-mo); margin: 22px 0 6px; }

/* ---------------------------------------------------------- nút */
.nut {
  display: block; width: 100%;
  min-height: 56px; padding: 15px 18px;
  border-radius: 14px; border: 1px solid var(--vien);
  background: var(--nen-3); color: var(--chu);
  font-size: 17px; font-family: inherit; font-weight: 520;
  cursor: pointer; text-align: center;
  transition: transform .08s ease, background .15s ease, border-color .15s ease;
}
.nut:active { transform: scale(.985); }
.nut.chinh {
  background: linear-gradient(180deg, var(--ngoc), color-mix(in srgb, var(--ngoc) 84%, #000));
  border-color: transparent; color: var(--chu-tren-ngoc); font-weight: 640;
}
.nut.am { background: transparent; }
.nut:disabled { opacity: .45; }

.hang-nut { display: flex; gap: 10px; }
.hang-nut .nut { flex: 1; }

/* ---------------------------------------------------------- tab dưới */
#thanh-tab {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 40;
  height: calc(var(--tab-cao) + var(--an-toan-duoi));
  padding-bottom: var(--an-toan-duoi);
  display: grid; grid-template-columns: repeat(4, 1fr);
  background: color-mix(in srgb, var(--nen-2) 92%, transparent);
  backdrop-filter: saturate(160%) blur(18px);
  -webkit-backdrop-filter: saturate(160%) blur(18px);
  border-top: 1px solid var(--vien);
}
#thanh-tab button {
  border: 0; background: none; color: var(--chu-rat-mo);
  font-family: inherit; font-size: 11px; cursor: pointer;
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 3px;
}
#thanh-tab .bt-icon {
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 20px; line-height: 1;
}
#thanh-tab button[aria-current="true"] { color: var(--ngoc); }
#thanh-tab.an { display: none; }

/* ---------------------------------------------------------- danh sách bài */
.the-khoa {
  border-radius: var(--bo-goc-to); padding: 18px; margin: 14px 0;
  border: 1px solid var(--vien); cursor: pointer;
  background: linear-gradient(140deg, var(--nen-2), var(--nen-3));
}
.the-khoa h2 { margin: 0 0 4px; font-size: 19px; font-weight: 620; }
.the-khoa p  { margin: 0; font-size: 14px; color: var(--chu-mo); }
.the-khoa .so { margin-top: 12px; font-size: 13px; color: var(--ngoc); }

.dong-bai {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 16px; margin: 8px 0;
  background: var(--nen-2); border: 1px solid var(--vien);
  border-radius: var(--bo-goc); cursor: pointer;
}
.dong-bai .so-bai {
  flex: 0 0 auto; width: 40px; height: 40px; border-radius: 12px;
  background: var(--nen-3); color: var(--chu-mo);
  display: grid; place-items: center; font-size: 14px; font-weight: 600;
}
.dong-bai.xong .so-bai { background: var(--ngoc-mo); color: var(--ngoc); }
.dong-bai .noi-dung { flex: 1; min-width: 0; }
.dong-bai .ten { font-weight: 560; }
.dong-bai .np  { font-size: 13px; color: var(--chu-rat-mo); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.dong-bai .sao { font-size: 13px; color: var(--ho-phach); letter-spacing: 1px; }

/* ---------------------------------------------------------- thanh chặng */
.thanh-chang { display: flex; gap: 6px; margin: 14px 0 4px; }
.thanh-chang button {
  flex: 1; height: 6px; border: 0; padding: 0; border-radius: 3px;
  background: var(--nen-3); cursor: pointer; position: relative;
}
.thanh-chang button::after {
  content: ""; position: absolute; inset: -12px -2px;
}
.thanh-chang button.xong { background: var(--ngoc); }
.thanh-chang button[aria-current="true"] { background: var(--ho-phach); }
.ten-chang { font-size: 13px; color: var(--chu-rat-mo); text-align: center; margin-bottom: 10px; }

/* ---------------------------------------------------------- thẻ từ mới */
.the-tu {
  text-align: center; padding: 34px 20px;
  background: linear-gradient(160deg, var(--nen-2), var(--nen-3));
  border: 1px solid var(--vien); border-radius: var(--bo-goc-to);
  box-shadow: var(--do-bong); margin: 16px 0;
}
.the-tu .hz  { font-size: 58px; line-height: 1.25; font-weight: 500; }
.the-tu .py  { font-size: 21px; margin-top: 8px; }
.the-tu .loai{ font-size: 12px; color: var(--chu-rat-mo); margin-top: 10px;
               border: 1px solid var(--vien); border-radius: 999px; padding: 3px 12px; display: inline-block; }
.the-tu .vi  { font-size: 19px; color: var(--chu); margin-top: 12px; }

.loa {
  border: 1px solid var(--vien); background: var(--nen-3); color: var(--ngoc);
  border-radius: 999px; padding: 9px 18px; font-size: 15px; font-family: inherit;
  cursor: pointer; min-height: 44px;
}
.loa.dang-doc { background: var(--ngoc-mo); border-color: var(--ngoc); }
.hang-loa { display: flex; gap: 10px; justify-content: center; margin-top: 18px; }

/* ---------------------------------------------------------- câu hỏi trắc nghiệm */
.cau-hoi { font-size: 15px; color: var(--chu-mo); margin: 18px 0 4px; }
.de-bai  { font-size: 27px; font-weight: 560; margin: 6px 0 20px; line-height: 1.35; }
.de-bai.nho { font-size: 20px; font-weight: 500; }

.dap-an {
  display: block; width: 100%; text-align: left;
  padding: 16px 18px; margin: 9px 0; min-height: 58px;
  border-radius: 14px; border: 1px solid var(--vien);
  background: var(--nen-2); color: var(--chu);
  font-size: 18px; font-family: inherit; cursor: pointer;
  transition: background .15s, border-color .15s;
}
.dap-an.dung { background: var(--dung-nen); border-color: var(--dung); color: var(--dung); }
.dap-an.sai  { background: var(--sai-nen);  border-color: var(--sai);  color: var(--sai); }
.dap-an:disabled { opacity: 1; }

/* dải kết quả trượt lên từ dưới */
.dai-ket-qua {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 50;
  padding: 18px 16px calc(18px + var(--an-toan-duoi));
  border-radius: 22px 22px 0 0;
  border-top: 1px solid var(--vien);
  animation: truot-len .22s ease;
}
@keyframes truot-len { from { transform: translateY(100%); } to { transform: none; } }
.dai-ket-qua.dung { background: color-mix(in srgb, var(--dung-nen) 100%, var(--nen-2)); }
.dai-ket-qua.sai  { background: color-mix(in srgb, var(--sai-nen)  100%, var(--nen-2)); }
.dai-ket-qua .nhan { font-weight: 660; margin-bottom: 4px; }
.dai-ket-qua.dung .nhan { color: var(--dung); }
.dai-ket-qua.sai  .nhan { color: var(--sai); }
.dai-ket-qua .giai { font-size: 15px; color: var(--chu-mo); margin-bottom: 14px; }

/* ---------------------------------------------------------- ghép câu */
.o-ghep {
  min-height: 96px; padding: 12px; border-radius: 14px;
  border: 1px dashed var(--vien); background: var(--nen-2);
  display: flex; flex-wrap: wrap; gap: 8px; align-content: flex-start;
}
.manh {
  padding: 11px 14px; border-radius: 11px; min-height: 46px;
  border: 1px solid var(--vien); background: var(--nen-3); color: var(--chu);
  font-size: 21px; font-family: inherit; cursor: pointer;
}
.manh.da-dung { opacity: .28; pointer-events: none; }
.kho-manh { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }

/* ---------------------------------------------------------- hội thoại */
.luot { display: flex; margin: 10px 0; }
.luot.A { justify-content: flex-start; }
.luot.B { justify-content: flex-end; }
.bong {
  max-width: 84%; padding: 12px 15px; border-radius: 18px;
  background: var(--nen-2); border: 1px solid var(--vien); cursor: pointer;
}
.luot.B .bong { background: var(--ngoc-mo); border-color: color-mix(in srgb, var(--ngoc) 40%, transparent); }
.bong .hz { font-size: 20px; }
.bong .py { font-size: 14px; display: block; margin-top: 3px; }
.bong .vi { font-size: 14px; display: block; margin-top: 5px; }
.bong.an-nghia .py, .bong.an-nghia .vi { display: none; }
.vai-nhan { font-size: 11px; color: var(--chu-rat-mo); margin-bottom: 3px; }

/* ---------------------------------------------------------- luyện nói */
.nut-mic {
  width: 92px; height: 92px; border-radius: 50%; margin: 22px auto; display: block;
  border: 2px solid var(--ngoc); background: var(--ngoc-mo); color: var(--ngoc);
  font-size: 32px; cursor: pointer;
}
.nut-mic.dang-ghi {
  border-color: var(--sai); color: var(--sai); background: var(--sai-nen);
  animation: dap .9s ease-in-out infinite;
}
@keyframes dap { 0%,100% { transform: scale(1); } 50% { transform: scale(1.07); } }

.cham-diem { display: flex; gap: 10px; margin: 16px 0; }
.o-diem { flex: 1; text-align: center; padding: 12px 6px; border-radius: 12px; background: var(--nen-2); border: 1px solid var(--vien); }
.o-diem .so { font-size: 24px; font-weight: 660; }
.o-diem .nhan { font-size: 11px; color: var(--chu-rat-mo); margin-top: 2px; }

.cau-tho { font-size: 30px; line-height: 1.7; text-align: center; margin: 10px 0; }
.cau-tho .tu { padding: 0 1px; border-radius: 4px; }
.cau-tho .tu.tot  { color: var(--dung); }
.cau-tho .tu.tam  { color: var(--tam); border-bottom: 2px solid var(--tam); }
.cau-tho .tu.kem  { color: var(--sai); border-bottom: 2px solid var(--sai); }

/* ---------------------------------------------------------- linh tinh */
.trong { text-align: center; color: var(--chu-rat-mo); padding: 44px 20px; }
.trong .to { font-size: 42px; margin-bottom: 10px; }

.vach { height: 1px; background: var(--vien); margin: 18px 0; border: 0; }

.o-nhap {
  width: 100%; padding: 14px; border-radius: 12px; min-height: 52px;
  border: 1px solid var(--vien); background: var(--nen-2); color: var(--chu);
  font-size: 16px; font-family: inherit;
}

input[type="range"] {
  width: 100%; height: 32px; background: none; accent-color: var(--ngoc);
  -webkit-appearance: none; appearance: none;
}
input[type="range"]::-webkit-slider-runnable-track { height: 5px; border-radius: 3px; background: var(--nen-3); }
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 26px; height: 26px; border-radius: 50%;
  background: var(--ngoc); border: 0; margin-top: -10px;
}
input[type="checkbox"] { accent-color: var(--ngoc); width: 20px; height: 20px; vertical-align: -4px; }
label { font-size: 14px; color: var(--chu-mo); }
select.o-nhap { appearance: none; -webkit-appearance: none; }
button:focus-visible, .dap-an:focus-visible, .manh:focus-visible {
  outline: 2px solid var(--ho-phach); outline-offset: 2px;
}

.chu-y {
  font-size: 14px; color: var(--chu-mo); line-height: 1.55;
  background: var(--ho-phach-mo); border: 1px solid color-mix(in srgb, var(--ho-phach) 32%, transparent);
  border-radius: 12px; padding: 13px 15px; margin: 12px 0;
}

.vong-tron { --p: 0; width: 38px; height: 38px; border-radius: 50%; flex: 0 0 auto;
  background: conic-gradient(var(--ngoc) calc(var(--p) * 1%), var(--nen-3) 0);
  display: grid; place-items: center; }
.vong-tron span { width: 28px; height: 28px; border-radius: 50%; background: var(--nen-2);
  display: grid; place-items: center; font-size: 11px; color: var(--chu-mo); }

table.bang { width: 100%; border-collapse: collapse; font-size: 15px; margin: 10px 0; display: block; overflow-x: auto; }
table.bang th, table.bang td { border: 1px solid var(--vien); padding: 9px 11px; text-align: left; vertical-align: top; }
table.bang th { background: var(--nen-3); color: var(--chu-mo); font-weight: 560; font-size: 13px; }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}