/* Giao diện SÁNG, tiếng Việt, cỡ chữ số nguyên (px). Không dark mode, không CDN. */
:root {
  --nen: #f7f7f4;
  --the: #ffffff;
  --muc: #1d1d1b;
  --mo: #5a5a55;
  --vien: #d8d6ce;
  --chinh: #b8352a;      /* đỏ FIG cho nút chính */
  --xanh: #1f6f4a;
  --vang: #fff4cf;
  --do-nhat: #fdeceb;
  --xanh-nhat: #eaf4ef;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--nen);
  color: var(--muc);
  font-family: "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  line-height: 22px;
}

main { max-width: 1100px; margin: 0 auto; padding: 16px 20px 48px; }

h1 { font-size: 24px; margin: 16px 0 4px; }
h2 { font-size: 19px; margin: 24px 0 8px; }
code { font-family: Consolas, "DejaVu Sans Mono", monospace; font-size: 13px; }

/* ---------------------------------------------------------- đầu trang */
.dau-trang {
  display: flex; align-items: center; gap: 24px; flex-wrap: wrap;
  background: var(--the); border-bottom: 1px solid var(--vien);
  padding: 10px 20px;
}
.ten-app { font-size: 18px; font-weight: 700; text-decoration: none; color: var(--muc); }
.ten-app span { color: var(--chinh); }
.dau-trang nav { display: flex; gap: 16px; }
.dau-trang nav a {
  text-decoration: none; color: var(--mo); font-size: 15px;
  padding: 4px 8px; border-radius: 4px;
}
.dau-trang nav a:hover { background: var(--nen); color: var(--muc); }
.dau-trang nav a.dang-o { background: var(--nen); color: var(--muc); font-weight: 600; }
.dau-trang .nguoi { margin-left: auto; font-size: 14px; color: var(--mo); }

.chan-trang {
  max-width: 1100px; margin: 0 auto; padding: 12px 20px 32px;
  color: var(--mo); font-size: 13px; border-top: 1px solid var(--vien);
}

/* ---------------------------------------------------------- khối chung */
.the {
  background: var(--the); border: 1px solid var(--vien); border-radius: 6px;
  padding: 16px; margin: 12px 0;
}
.the-chon { display: flex; align-items: flex-end; gap: 12px; flex-wrap: wrap;
  background: var(--the); border: 1px solid var(--vien); border-radius: 6px;
  padding: 12px 16px; margin: 8px 0; }
.the-chon .o { flex: 1 1 420px; }

.luoi { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 12px 16px; }

.o { display: flex; flex-direction: column; gap: 4px; font-size: 14px; }
.o > span { font-weight: 600; }
.o em { color: var(--mo); font-size: 13px; font-style: normal; line-height: 18px; }
.o-rong { grid-column: 1 / -1; }
.o-tich { flex-direction: row; align-items: baseline; gap: 8px; flex-wrap: wrap; }
.o-tich em { flex-basis: 100%; }
.da-doi { color: var(--chinh); font-size: 13px; }

input, select, button, textarea { font-family: inherit; font-size: 15px; }
input[type=text], input[type=password], input[type=number], input:not([type]), select {
  padding: 6px 8px; border: 1px solid var(--vien); border-radius: 4px;
  background: #fff; color: var(--muc); width: 100%;
}
input[type=file] { font-size: 14px; }
input:disabled { background: #f0f0ec; color: var(--mo); }

details.gap { margin: 12px 0; border: 1px solid var(--vien); border-radius: 6px; background: #fcfcfa; }
details.gap > summary {
  cursor: pointer; padding: 10px 14px; font-weight: 600; font-size: 15px;
  list-style: none;
}
details.gap > summary::before { content: "▸ "; color: var(--mo); }
details.gap[open] > summary::before { content: "▾ "; }
details.gap > div, details.gap > .tai-ve { padding: 4px 14px 14px; }

.hang-nut { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 16px; }
.nut {
  display: inline-block; padding: 9px 16px; border-radius: 4px; cursor: pointer;
  border: 1px solid var(--vien); background: #fff; color: var(--muc);
  text-decoration: none; font-size: 15px;
}
.nut:hover { background: var(--nen); }
.nut-chinh { background: var(--chinh); border-color: var(--chinh); color: #fff; font-weight: 600; }
.nut-chinh:hover { background: #9c2c22; }
.nut-nho { padding: 5px 10px; font-size: 13px; }
.nut-tai { display: inline-block; margin: 4px 8px 4px 0; }

/* ---------------------------------------------------------- băng báo */
.bang { padding: 10px 14px; border-radius: 5px; margin: 12px 0; font-size: 14px; }
.bang-do { background: var(--do-nhat); border: 1px solid #e3b4b0; color: #8d2a22; }
.bang-vang { background: var(--vang); border: 1px solid #e3d195; color: #6b5310; }
.bang-xanh { background: var(--xanh-nhat); border: 1px solid #b6d6c5; color: #1d5b3f; }

.chu-nho { color: var(--mo); font-size: 13px; line-height: 19px; }

/* ---------------------------------------------------------- kết quả */
.ket-qua { margin-top: 24px; }
.stdout {
  background: #22231f; color: #eceade; padding: 12px 14px; border-radius: 6px;
  font-family: Consolas, "DejaVu Sans Mono", monospace; font-size: 13px; line-height: 19px;
  overflow-x: auto; white-space: pre-wrap; word-break: break-word;
}
.xem-truoc { max-width: 100%; border: 1px solid var(--vien); background: #fff; padding: 6px; }
.trang-thai { font-size: 13px; padding: 2px 8px; border-radius: 10px; border: 1px solid var(--vien); }
.tt-xong { background: var(--xanh-nhat); color: #1d5b3f; }
.tt-loi, .tt-qua_gio { background: var(--do-nhat); color: #8d2a22; }
.tt-dang_chay, .tt-dang_cho { background: var(--vang); color: #6b5310; }

.ba-file { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 12px; margin: 12px 0; }
.the-file {
  display: flex; gap: 12px; background: var(--the); border: 1px solid var(--vien);
  border-radius: 6px; padding: 12px;
}
.the-file .so { font-size: 28px; line-height: 30px; color: var(--chinh); }
.the-file p { margin: 2px 0 6px; }
.the-thieu { border-color: #e3b4b0; background: var(--do-nhat); }

.bang-viec { border-collapse: collapse; width: 100%; background: var(--the); font-size: 14px; }
.bang-viec th, .bang-viec td { border: 1px solid var(--vien); padding: 6px 10px; text-align: left; }
.bang-viec th { background: var(--nen); font-size: 13px; }

/* ---------------------------------------------------------- đăng nhập */
.hop-dang-nhap {
  max-width: 380px; margin: 48px auto; background: var(--the);
  border: 1px solid var(--vien); border-radius: 6px; padding: 24px;
}
.hop-dang-nhap form { display: flex; flex-direction: column; gap: 6px; }
.hop-dang-nhap label { font-weight: 600; font-size: 14px; margin-top: 8px; }
.hop-dang-nhap button { margin-top: 16px; }