/* rain8n.com: sổ tay tự động hoá cho chủ doanh nghiệp nhỏ.
   Màu khai đủ ở :root, khối tối chỉ ghi đè. */
:root {
  --nen: #f2f4f3;          /* sương: nền trang */
  --mat: #ffffff;          /* mặt: khối nổi, bảng */
  --muc: #17212b;          /* mực: chữ chính */
  --muc-phu: #4b5966;      /* mực phụ: chữ phụ, ngày tháng */
  --vien: #8d9aa3;         /* viền ô, nút: đạt 3:1 trên nền */
  --ke: #d5dcdf;           /* đường kẻ trang trí */
  --nhan: #0b6a60;         /* xanh mạch: nhấn duy nhất */
  --nhan-dam: #084d46;
  --nhan-nhat: #dcefeb;
  --code-nen: #1a222a;
  --code-chu: #e4ebee;
  --code-nhat: #8fd3c7;
  --luu-y-nen: #fbf1de;
  --luu-y-chu: #5c3a00;
  --luu-y-vien: #c58a2a;
  --rong: 72rem;
  --doc: 42rem;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --nen: #10161b; --mat: #172028; --muc: #e2e9ec; --muc-phu: #a3b0ba;
    --vien: #6c7a85; --ke: #2b3740; --nhan: #5cc4b4; --nhan-dam: #8adccf; --nhan-nhat: #173a36;
    --code-nen: #0a0f13; --code-chu: #e4ebee; --code-nhat: #8fd3c7;
    --luu-y-nen: #2e2410; --luu-y-chu: #f3d9a6; --luu-y-vien: #b98a3a;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --nen: #10161b; --mat: #172028; --muc: #e2e9ec; --muc-phu: #a3b0ba;
  --vien: #6c7a85; --ke: #2b3740; --nhan: #5cc4b4; --nhan-dam: #8adccf; --nhan-nhat: #173a36;
  --code-nen: #0a0f13; --code-chu: #e4ebee; --code-nhat: #8fd3c7;
  --luu-y-nen: #2e2410; --luu-y-chu: #f3d9a6; --luu-y-vien: #b98a3a;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; background: var(--nen); }
body {
  margin: 0; background: var(--nen); color: var(--muc);
  font-family: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 1.0625rem; line-height: 1.7;
}
a { color: var(--nhan); text-underline-offset: 3px; }
a:hover { color: var(--nhan-dam); }
:focus-visible { outline: 3px solid var(--nhan); outline-offset: 2px; border-radius: 2px; }
code, pre, .mono { font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace; }
img, svg { max-width: 100%; }
.skip { position: absolute; left: -999px; top: 0; background: var(--mat); padding: .5rem 1rem; }
.skip:focus { left: 1rem; z-index: 10; }

/* Đầu trang */
.dau { border-bottom: 1px solid var(--ke); background: var(--nen); }
.dau-trong { max-width: var(--rong); margin: 0 auto; padding: .9rem 1rem; display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.logo { font-family: "JetBrains Mono", monospace; font-weight: 700; font-size: 1.05rem; color: var(--muc); text-decoration: none; letter-spacing: -.01em; }
.logo span { color: var(--nhan); }
.dau nav { display: flex; gap: 1.25rem; flex-wrap: wrap; }
.dau nav a { color: var(--muc); text-decoration: none; font-size: .95rem; padding: .35rem 0; min-height: 24px; }
.dau nav a:hover, .dau nav a[aria-current="page"] { color: var(--nhan); text-decoration: underline; }

main { display: block; }
.khung { max-width: var(--rong); margin: 0 auto; padding: 0 1rem; }

/* Trang chủ: khối mở đầu */
.mo-dau { padding: clamp(2.5rem, 7vw, 5rem) 0 2rem; display: grid; grid-template-columns: 1fr; gap: 2.5rem; align-items: center; }
@media (min-width: 900px) { .mo-dau { grid-template-columns: 1.05fr 1fr; } }
.mo-dau h1 { font-size: clamp(2rem, 4.6vw, 3.2rem); line-height: 1.15; margin: 0 0 1rem; letter-spacing: -.02em; font-weight: 700; max-width: 18ch; }
.mo-dau p.phu { font-size: 1.15rem; color: var(--muc-phu); margin: 0 0 1.75rem; max-width: 34rem; }
.nut { display: inline-block; background: var(--nhan); color: #fff; text-decoration: none; font-weight: 600; padding: .8rem 1.3rem; border-radius: 6px; border: 1px solid var(--nhan-dam); }
.nut:hover { background: var(--nhan-dam); color: #fff; }
:root[data-theme="dark"] .nut, :root[data-theme="dark"] .nut:hover { color: #0b1512; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .nut, :root:not([data-theme="light"]) .nut:hover { color: #0b1512; } }

/* Sơ đồ luồng (phần tử chữ ký) */
.so-do { background: var(--mat); border: 1px solid var(--ke); border-radius: 10px; padding: 1rem; margin: 1.75rem 0; }
.so-do svg { display: block; width: 100%; height: auto; }
.so-do figcaption { font-size: .9rem; color: var(--muc-phu); margin-top: .6rem; }
.so-do .nut-luong { fill: var(--nen); stroke: var(--vien); stroke-width: 1.5; }
.so-do .nut-luong.chinh { fill: var(--nhan-nhat); stroke: var(--nhan); }
.so-do .chu { fill: var(--muc); font: 600 15px "Be Vietnam Pro", sans-serif; }
.so-do .chu-nho { fill: var(--muc-phu); font: 12.5px "JetBrains Mono", monospace; }
.so-do .day { stroke: var(--nhan); stroke-width: 2; fill: none; }
.so-do .mui { fill: var(--nhan); }

/* Danh sách bài */
.muc-tieu-de { font-size: 1.5rem; margin: 3rem 0 1rem; letter-spacing: -.01em; }
.ds-bai { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--ke); }
.ds-bai li { border-bottom: 1px solid var(--ke); padding: 1.25rem 0; display: grid; grid-template-columns: 1fr; gap: .35rem; }
@media (min-width: 760px) { .ds-bai li { grid-template-columns: 9rem 1fr; gap: 1.5rem; } }
.ds-bai time { color: var(--muc-phu); font-size: .9rem; font-family: "JetBrains Mono", monospace; padding-top: .2rem; }
.ds-bai h3 { margin: 0 0 .3rem; font-size: 1.2rem; line-height: 1.35; }
.ds-bai h3 a { color: var(--muc); text-decoration: none; }
.ds-bai h3 a:hover { color: var(--nhan); text-decoration: underline; }
.ds-bai p { margin: 0 0 .5rem; color: var(--muc-phu); }
.chuoi { font-family: "JetBrains Mono", monospace; font-size: .82rem; color: var(--nhan-dam); background: var(--nhan-nhat); padding: .15rem .5rem; border-radius: 4px; display: inline-block; }
:root[data-theme="dark"] .chuoi { color: var(--nhan-dam); }

/* Khối nguyên tắc trang chủ */
.nguyen-tac { display: grid; grid-template-columns: 1fr; gap: 2rem; margin: 3.5rem 0; padding: 2rem 0; border-top: 1px solid var(--ke); }
@media (min-width: 900px) { .nguyen-tac { grid-template-columns: 20rem 1fr; } }
.nguyen-tac h2 { margin: 0; font-size: 1.5rem; line-height: 1.3; }
.nguyen-tac ol { margin: 0; padding-left: 1.25rem; }
.nguyen-tac li { margin-bottom: 1rem; }
.nguyen-tac li strong { display: block; }

/* Bài viết */
.bai { max-width: var(--doc); margin: 0 auto; padding: 2rem 1rem 3rem; }
.vet { font-size: .9rem; color: var(--muc-phu); margin-bottom: 1.5rem; }
.vet a { color: var(--muc-phu); }
.bai h1 { font-size: clamp(1.85rem, 4vw, 2.5rem); line-height: 1.2; margin: 0 0 .9rem; letter-spacing: -.015em; }
.bai .sub { font-size: 1.15rem; color: var(--muc-phu); margin: 0 0 1rem; }
.meta { font-size: .9rem; color: var(--muc-phu); display: flex; flex-wrap: wrap; gap: .4rem 1rem; padding-bottom: 1.25rem; border-bottom: 1px solid var(--ke); margin-bottom: 2rem; }
.bai h2 { font-size: 1.5rem; line-height: 1.3; margin: 2.5rem 0 .75rem; scroll-margin-top: 1rem; }
.bai h3 { font-size: 1.15rem; margin: 1.75rem 0 .5rem; }
.bai p, .bai li { max-width: 68ch; }
.bai ol, .bai ul { padding-left: 1.3rem; }
.bai li { margin-bottom: .45rem; }
.bai code { font-size: .88em; background: var(--nhan-nhat); padding: .08em .35em; border-radius: 3px; overflow-wrap: anywhere; }
.bai pre { background: var(--code-nen); color: var(--code-chu); padding: 1rem 1.1rem; border-radius: 8px; overflow-x: auto; font-size: .86rem; line-height: 1.6; margin: 1.25rem 0; }
.bai pre code { background: none; padding: 0; color: inherit; font-size: inherit; overflow-wrap: normal; }
.bai pre .cm { color: #9aa8b2; }
.bai pre .hl { color: var(--code-nhat); }
.tom-tat { background: var(--mat); border: 1px solid var(--ke); border-left: 4px solid var(--nhan); padding: 1rem 1.25rem; border-radius: 6px; margin: 1.5rem 0; }
.tom-tat p { margin: 0 0 .4rem; font-weight: 600; }
.tom-tat ul { margin: 0; }
.luu-y { background: var(--luu-y-nen); color: var(--luu-y-chu); border: 1px solid var(--luu-y-vien); padding: .9rem 1.1rem; border-radius: 6px; margin: 1.5rem 0; }
.luu-y a { color: inherit; }
.bang { width: 100%; border-collapse: collapse; margin: 1.25rem 0; font-size: .95rem; background: var(--mat); }
.cuon-bang { overflow-x: auto; }
.bang th, .bang td { border: 1px solid var(--ke); padding: .55rem .7rem; text-align: left; vertical-align: top; }
.bang th { background: var(--nhan-nhat); }
.buoc-tiep { border-top: 1px solid var(--ke); border-bottom: 1px solid var(--ke); padding: 1.25rem 0; margin: 2.5rem 0; }
.buoc-tiep p { margin: 0 0 .5rem; }
.faq details { border-bottom: 1px solid var(--ke); padding: .75rem 0; }
.faq summary { cursor: pointer; font-weight: 600; min-height: 24px; }
.faq .faq-a p { margin: .6rem 0 0; }
.lien-quan { margin-top: 2.5rem; }
.lien-quan h2 { font-size: 1.2rem; }

/* Giới thiệu */
.trang-tinh { max-width: var(--doc); margin: 0 auto; padding: 2.5rem 1rem 3rem; }
.trang-tinh h1 { font-size: clamp(1.9rem, 4vw, 2.5rem); line-height: 1.2; margin: 0 0 1rem; }
.trang-tinh h2 { font-size: 1.35rem; margin: 2.25rem 0 .6rem; }

/* Chân trang */
.chan { border-top: 1px solid var(--ke); margin-top: 3rem; padding: 2rem 0 2.5rem; font-size: .9rem; color: var(--muc-phu); }
.chan-trong { max-width: var(--rong); margin: 0 auto; padding: 0 1rem; display: grid; gap: 1rem; grid-template-columns: 1fr; }
@media (min-width: 760px) { .chan-trong { grid-template-columns: 2fr 1fr; } }
.chan p { margin: 0 0 .5rem; }
.chan a { color: var(--muc-phu); }
.chan nav { display: flex; flex-direction: column; gap: .35rem; }

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