/* ==========================================================================
   NĂNG LỰC SỐ — THPT Trần Nguyên Hãn
   Bảng màu lấy từ mẫu nhận diện của trường (Mau_Slide_THPT_TranNguyenHan).
   ========================================================================== */

:root {
  --navy: #053596;
  --navy-dark: #042b7b;
  --blue: #1e4fb0;
  --cyan: #0e7c9b;
  --teal: #12776a;
  --amber: #d9821e;
  --red: #d42821;

  --ink: #1b2438;
  --muted: #5b6472;
  --faint: #8a93a3;
  --line: #dde3ee;
  --soft: #f5f7fa;
  --card: #eaf0fb;
  --paper: #ffffff;

  --shadow-sm: 0 1px 2px rgba(5, 53, 150, .06), 0 2px 8px rgba(5, 53, 150, .05);
  --shadow-md: 0 4px 12px rgba(5, 53, 150, .08), 0 12px 32px rgba(5, 53, 150, .07);
  --radius: 14px;
  --max: 1180px;
  --font: "Segoe UI", Arial, "Helvetica Neue", Helvetica, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: var(--navy); }

.bao { width: 100%; max-width: var(--max); margin-inline: auto; padding-inline: 20px; }

/* ----------------------------------------------------------------- ĐẦU TRANG */
.dinh {
  position: sticky; top: 0; z-index: 60;
  background: rgba(255, 255, 255, .94);
  backdrop-filter: saturate(1.6) blur(10px);
  border-bottom: 1px solid var(--line);
}
.dinh-trong { display: flex; align-items: center; gap: 14px; height: 66px; }
.hieu { display: flex; align-items: center; gap: 11px; text-decoration: none; color: inherit; flex-shrink: 0; }
.hieu img { width: 40px; height: 40px; }
.hieu-chu { display: flex; flex-direction: column; line-height: 1.16; }
.hieu-chu b { font-size: 15px; color: var(--navy); letter-spacing: .01em; }
.hieu-chu span { font-size: 11.5px; color: var(--muted); }

.menu { margin-left: auto; display: flex; align-items: center; gap: 4px; }
.menu a {
  padding: 8px 14px; border-radius: 9px; text-decoration: none;
  color: var(--ink); font-size: 14.5px; font-weight: 600; white-space: nowrap;
}
.menu a:hover { background: var(--card); color: var(--navy); }
.menu a.dang { background: var(--navy); color: #fff; }

.nut-menu { display: none; margin-left: auto; background: none; border: 1px solid var(--line);
  border-radius: 9px; padding: 8px 11px; font-size: 17px; cursor: pointer; color: var(--navy); }

@media (max-width: 900px) {
  .nut-menu { display: block; }
  .menu {
    position: absolute; top: 66px; left: 0; right: 0; flex-direction: column;
    align-items: stretch; gap: 2px; padding: 10px 16px 16px;
    background: #fff; border-bottom: 1px solid var(--line); box-shadow: var(--shadow-md);
    display: none;
  }
  .menu.mo { display: flex; }
  .hieu-chu b { font-size: 13.5px; }
}

/* ------------------------------------------------------------------ TRANG BÌA */
.bia {
  position: relative; overflow: hidden; color: #fff;
  background:
    radial-gradient(1100px 460px at 82% -8%, #1348bd 0%, transparent 62%),
    linear-gradient(140deg, var(--navy) 0%, var(--navy-dark) 100%);
}
.bia::after {
  content: ""; position: absolute; inset: auto 0 0 0; height: 6px; background: var(--red);
}
.bia-trong { display: grid; grid-template-columns: 1.15fr .85fr; gap: 46px; align-items: center;
  padding: 66px 20px 74px; }
.the-nhan {
  display: inline-flex; align-items: center; gap: 8px; background: var(--red);
  color: #fff; font-size: 12.5px; font-weight: 700; letter-spacing: .09em;
  padding: 7px 15px; border-radius: 999px; text-transform: uppercase;
}
.bia h1 { font-size: clamp(34px, 5.2vw, 56px); line-height: 1.06; margin: 20px 0 12px; letter-spacing: -.02em; }
.bia .phu { font-size: clamp(17px, 2.1vw, 21px); color: #c9daf2; font-weight: 600; margin: 0 0 22px; }
.bia .mo { color: #b7c9e4; max-width: 46ch; margin: 0 0 30px; font-size: 15.5px; }
.gach { width: 84px; height: 4px; background: var(--red); border-radius: 3px; margin: 0 0 22px; }

.nut-hang { display: flex; flex-wrap: wrap; gap: 12px; }
.nut {
  display: inline-flex; align-items: center; gap: 9px; padding: 13px 22px;
  border-radius: 11px; text-decoration: none; font-weight: 700; font-size: 15px;
  transition: transform .15s ease, box-shadow .15s ease, background .15s ease;
}
.nut:hover { transform: translateY(-1px); }
.nut-chinh { background: #fff; color: var(--navy); box-shadow: var(--shadow-md); }
.nut-chinh:hover { background: #f2f6ff; }
.nut-vien { border: 1.5px solid rgba(255, 255, 255, .5); color: #fff; }
.nut-vien:hover { background: rgba(255, 255, 255, .1); border-color: #fff; }

/* bảng số liệu trên bìa */
.so-lieu { background: rgba(255, 255, 255, .07); border: 1px solid rgba(255, 255, 255, .16);
  border-radius: var(--radius); padding: 26px 28px; }
.so-lieu h3 { margin: 0 0 18px; font-size: 12px; letter-spacing: .1em; color: #8fa8cc; text-transform: uppercase; }
.so-lieu-dong { display: flex; align-items: center; gap: 16px; padding: 13px 0; }
.so-lieu-dong + .so-lieu-dong { border-top: 1px solid rgba(255, 255, 255, .13); }
.so-lieu-dong b { font-size: 34px; line-height: 1; min-width: 58px; letter-spacing: -.02em; }
.so-lieu-dong span { font-size: 14px; color: #c2d5f0; }

@media (max-width: 900px) {
  .bia-trong { grid-template-columns: 1fr; gap: 34px; padding: 46px 20px 54px; }
}

/* --------------------------------------------------------------------- KHỐI */
.khoi { padding: 68px 0; }
.khoi.xam { background: var(--soft); border-block: 1px solid var(--line); }
.dau-khoi { max-width: 62ch; margin: 0 0 38px; }
.dau-khoi .nhan { font-size: 12px; font-weight: 800; letter-spacing: .1em; color: var(--red);
  text-transform: uppercase; display: block; margin-bottom: 10px; }
.dau-khoi h2 { font-size: clamp(25px, 3.4vw, 34px); margin: 0 0 12px; color: var(--navy); letter-spacing: -.015em; }
.dau-khoi p { margin: 0; color: var(--muted); font-size: 16px; }

.luoi { display: grid; gap: 20px; }
.luoi-3 { grid-template-columns: repeat(3, 1fr); }
.luoi-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 900px) { .luoi-3, .luoi-2 { grid-template-columns: 1fr; } }

.the {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 24px; box-shadow: var(--shadow-sm);
  transition: transform .16s ease, box-shadow .16s ease, border-color .16s ease;
  display: flex; flex-direction: column;
}
a.the { text-decoration: none; color: inherit; }
a.the:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: #c3d3ef; }
.the-dau { width: 46px; height: 46px; border-radius: 12px; display: grid; place-items: center;
  font-size: 21px; margin-bottom: 16px; background: var(--card); color: var(--navy); }
.the h3 { margin: 0 0 9px; font-size: 19px; color: var(--navy); }
.the p { margin: 0; color: var(--muted); font-size: 14.8px; }
.the .di { margin-top: 16px; font-weight: 700; font-size: 14px; color: var(--navy); }

.vach { height: 4px; border-radius: 3px 3px 0 0; margin: -26px -24px 20px; }
.v-navy { background: var(--navy); } .v-blue { background: var(--blue); }
.v-cyan { background: var(--cyan); } .v-teal { background: var(--teal); }
.v-amber { background: var(--amber); } .v-red { background: var(--red); }

/* danh sách buổi */
.buoi { display: grid; grid-template-columns: 108px 1fr; gap: 22px; align-items: start;
  padding: 24px 0; border-top: 1px solid var(--line); }
.buoi:first-of-type { border-top: 0; }
.buoi .so { font-size: 44px; font-weight: 800; color: #c3d3ef; line-height: 1; letter-spacing: -.03em; }
.buoi h3 { margin: 0 0 6px; font-size: 21px; color: var(--navy); }
.buoi p { margin: 0 0 12px; color: var(--muted); font-size: 15px; }
.chip-hang { display: flex; flex-wrap: wrap; gap: 7px; }
.chip { font-size: 12.5px; font-weight: 600; padding: 5px 11px; border-radius: 999px;
  background: var(--card); color: var(--navy); border: 1px solid #d3e0f6; }
@media (max-width: 640px) { .buoi { grid-template-columns: 1fr; gap: 8px; } .buoi .so { font-size: 34px; } }

/* -------------------------------------------------------------- CHÂN TRANG */
.chan { background: var(--navy); color: #b7c9e4; padding: 46px 0 0; margin-top: 20px; }
.chan-luoi { display: grid; grid-template-columns: 1.5fr 1fr 1fr; gap: 34px; padding-bottom: 34px; }
.chan h4 { color: #fff; font-size: 14px; margin: 0 0 14px; letter-spacing: .04em; }
.chan a { color: #b7c9e4; text-decoration: none; font-size: 14.5px; display: block; padding: 4px 0; }
.chan a:hover { color: #fff; }
.chan .hieu-chan { display: flex; align-items: center; gap: 12px; margin-bottom: 14px; }
.chan .hieu-chan img { width: 46px; height: 46px; }
.chan .hieu-chan b { color: #fff; font-size: 16px; }
.chan p { font-size: 14.2px; margin: 0 0 8px; }
.chan-day { border-top: 1px solid rgba(255, 255, 255, .14); padding: 18px 0 24px;
  font-size: 13px; color: #8fa8cc; display: flex; flex-wrap: wrap; gap: 10px 20px; justify-content: space-between; }
@media (max-width: 900px) { .chan-luoi { grid-template-columns: 1fr; gap: 24px; } }

/* ------------------------------------------------------- TRANG TRONG (đầu) */
.dau-trang-trong { background: linear-gradient(140deg, var(--navy), var(--navy-dark));
  color: #fff; padding: 40px 0 34px; border-bottom: 6px solid var(--red); }
.dau-trang-trong h1 { margin: 10px 0 8px; font-size: clamp(25px, 3.6vw, 35px); letter-spacing: -.015em; }
.dau-trang-trong p { margin: 0; color: #c2d5f0; font-size: 15.5px; max-width: 72ch; }
.duong-dan { font-size: 13px; color: #9fb8dc; }
.duong-dan a { color: #9fb8dc; text-decoration: none; }
.duong-dan a:hover { color: #fff; }

.hop-canh-bao { background: #fdf4e4; border: 1px solid #f0d9ae; border-left: 4px solid var(--amber);
  border-radius: 10px; padding: 15px 18px; color: #6b4e13; font-size: 14.5px; margin: 20px 0; }