/* Khu "Bản đồ làm online" — cùng nhận diện Biển – Cát – San hô với trang chủ */
:root {
  --bien: #1f6f78; --bien-dam: #154f56; --cat: #f4ede1; --cat-dam: #e8dcc8;
  --san-ho: #c4542f; --muc: #1d2b2f; --xam: #5d6b6e; --trang: #fffdf9; --vien: #e3d7c3;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --cat: #172022; --cat-dam: #1f2b2e; --trang: #1b2527; --muc: #eef0ec; --xam: #a8b4b2; --vien: #2e3c3f; --bien: #5fb3ba; --bien-dam: #8fd0d5; --san-ho: #f0937a;
  }
}
:root[data-theme="dark"] {
  --cat: #172022; --cat-dam: #1f2b2e; --trang: #1b2527; --muc: #eef0ec; --xam: #a8b4b2; --vien: #2e3c3f; --bien: #5fb3ba; --bien-dam: #8fd0d5; --san-ho: #f0937a;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--cat); color: var(--muc); font: 17px/1.7 "Be Vietnam Pro", system-ui, sans-serif; }
a { color: var(--bien); }
.wrap { max-width: 760px; margin: 0 auto; padding: 0 16px 48px; }
header.top { display: flex; flex-wrap: wrap; gap: 8px 16px; align-items: center; justify-content: space-between; padding: 18px 0; }
.logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; color: var(--muc); text-decoration: none; }
.logo b { width: 34px; height: 34px; border-radius: 50%; background: var(--bien); color: #fff; display: grid; place-items: center; font-size: 14px; }
nav.khu { display: flex; flex-wrap: wrap; gap: 4px 14px; font-size: 15px; }
nav.khu a { text-decoration: none; font-weight: 600; }
nav.khu a[aria-current="page"] { color: var(--muc); }
h1 { font-size: clamp(26px, 5.5vw, 38px); line-height: 1.2; margin: 20px 0 10px; letter-spacing: -.3px; }
h2 { font-size: 23px; line-height: 1.3; margin: 40px 0 10px; padding-top: 16px; border-top: 1px solid var(--vien); }
h3 { font-size: 19px; margin: 28px 0 8px; }
p, li { overflow-wrap: anywhere; }
.meta, .sub { color: var(--xam); }
blockquote { margin: 16px 0; padding: 12px 16px; background: var(--trang); border-left: 4px solid var(--bien); border-radius: 0 10px 10px 0; }
.the { background: var(--trang); border: 1px solid var(--vien); border-radius: 14px; padding: 18px 20px; margin: 16px 0; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(220px, 100%), 1fr)); gap: 14px; }
.grid .the { margin: 0; }
.the h3 { margin-top: 0; }
.btn { display: inline-block; background: var(--bien); color: #fff; text-decoration: none; font-weight: 600; padding: 11px 20px; border-radius: 10px; border: 0; font: inherit; cursor: pointer; margin: 4px 8px 4px 0; }
.btn.phu { background: transparent; color: var(--bien); box-shadow: inset 0 0 0 2px var(--bien); }
.btn:disabled { opacity: .6; cursor: wait; }
.so { font-size: 30px; font-weight: 800; color: var(--san-ho); line-height: 1.1; }
.muc-luc { font-size: 15px; }
.muc-luc ol { padding-left: 20px; margin: 6px 0; }
label.f { display: block; font-weight: 600; margin: 14px 0 4px; }
label.f small { font-weight: 400; color: var(--xam); }
input[type=text], textarea { width: 100%; font: inherit; padding: 10px 12px; border: 1px solid var(--vien); border-radius: 10px; background: var(--trang); color: var(--muc); }
textarea { min-height: 140px; resize: vertical; }
label.check { display: flex; gap: 10px; align-items: flex-start; margin: 12px 0; }
label.check input { margin-top: 6px; width: 18px; height: 18px; flex: none; }
.bay { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }
.tb { padding: 10px 14px; border-radius: 10px; margin-top: 12px; }
.tb.ok { background: #e3f3ea; color: #1d5b3a; }
.tb.loi { background: #fbe6df; color: #8a3018; }
footer { margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--vien); color: var(--xam); font-size: 14px; }
:focus-visible { outline: 3px solid var(--san-ho); outline-offset: 2px; }

/* Dễ đọc: gạch đầu dòng giãn ra */
li { margin: 6px 0; }
li + li { margin-top: 10px; }

/* Mục lục: luôn mở; máy tính màn rộng thì đứng cố định bên trái; điện thoại có nút "Mục lục" nổi */
.muc-luc summary { cursor: pointer; }
.muc-luc li { margin: 4px 0; }
.muc-luc a { text-decoration: none; }
.muc-luc a.dang-doc { font-weight: 800; color: var(--san-ho); }
.nut-ml { position: fixed; right: 14px; bottom: 16px; z-index: 20; background: var(--bien); color: #fff; border-radius: 99px; padding: 10px 16px; font-weight: 700; text-decoration: none; box-shadow: 0 4px 14px rgba(0,0,0,.2); }
@media (min-width: 1240px) {
  .muc-luc { position: fixed; left: 16px; top: 24px; width: 250px; max-height: calc(100vh - 48px); overflow: auto; margin: 0; font-size: 14px; }
  .nut-ml { display: none; }
}

/* Mềm mại hơn: bo góc, bóng nhẹ, chuyển động êm, khoảng thở rộng (thêm 24/10/2026) */
html { scroll-behavior: smooth; }
body { -webkit-font-smoothing: antialiased; }
h2 { letter-spacing: -.2px; }
.the { border-radius: 18px; padding: 20px 22px; box-shadow: 0 1px 2px rgba(29,43,47,.04), 0 6px 18px rgba(29,43,47,.06); transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease; }
a.the:hover, .the.khoa:hover, .the.sp:hover { transform: translateY(-2px); box-shadow: 0 2px 4px rgba(29,43,47,.05), 0 12px 28px rgba(29,43,47,.10); border-color: var(--bien); }
.grid { gap: 16px; }
.btn { border-radius: 12px; padding: 11px 20px; transition: transform .15s ease, filter .15s ease, background .15s ease; }
.btn:hover { filter: brightness(1.06); transform: translateY(-1px); }
.btn:active { transform: translateY(0) scale(.98); }
input[type=text], textarea, input[type=email], input[type=tel] { border-radius: 12px; transition: border-color .15s ease, box-shadow .15s ease; }
input:focus, textarea:focus { outline: none; border-color: var(--bien); box-shadow: 0 0 0 3px rgba(31,111,120,.18); }
p { margin: 0 0 14px; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } .the, .btn { transition: none; } }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .the { box-shadow: 0 1px 2px rgba(0,0,0,.3), 0 8px 22px rgba(0,0,0,.25); } }