/* ==========================================================================
   Rumus Cloud - sistem desain
   Arah: panel kerja korporat yang padat informasi.
   Aturan yang dipegang: tanpa gradien, tanpa emoji, radius maksimal 6px,
   permukaan rata dengan garis tepi tegas, kontras teks tinggi.
   ========================================================================== */

:root {
  /* Warna dasar: navy tua sebagai permukaan gelap, netral hangat untuk terang */
  --navy-950: #0A1524;
  --navy-900: #0E1B2C;
  --navy-800: #16263C;
  --navy-700: #1E3350;
  --navy-600: #2A4667;
  --navy-500: #3B5C82;

  --ink-900: #101826;
  --ink-700: #2A3444;
  --ink-500: #4A5568;
  --ink-400: #6B7688;

  --paper: #FFFFFF;
  --paper-2: #FAFAF8;
  --paper-3: #F3F3EF;
  --line: #E2E1DB;
  --line-strong: #CFCEC6;

  /* Aksen tunggal: tembaga, dipakai tipis dan hanya untuk penanda */
  --copper-700: #8A5A22;
  --copper-600: #A56B27;
  --copper-500: #C08234;
  --copper-100: #F7EDDD;

  --ok-700: #1F6B44;
  --ok-100: #E4F1EA;
  --warn-700: #8A5B00;
  --warn-100: #FBF1DA;
  --stop-700: #9B2C2C;
  --stop-100: #FBEAEA;

  --font-sans: 'IBM Plex Sans', -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'IBM Plex Mono', 'SFMono-Regular', Consolas, monospace;

  --w: 1180px;
  --radius: 4px;
  --shadow-sm: 0 1px 2px rgba(16, 24, 38, 0.06);
  --shadow-md: 0 4px 12px -4px rgba(16, 24, 38, 0.12);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.62;
  color: var(--ink-700);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  color: var(--ink-900);
  line-height: 1.25;
  letter-spacing: -0.015em;
  margin: 0 0 0.5em;
  font-weight: 600;
}

h1 { font-size: 34px; }
h2 { font-size: 23px; margin-top: 2em; }
h3 { font-size: 17px; margin-top: 1.6em; }

p { margin: 0 0 1em; }
a { color: var(--navy-700); text-decoration: none; border-bottom: 1px solid rgba(30, 51, 80, 0.25); }
a:hover { border-bottom-color: var(--navy-700); }

code, pre, kbd {
  font-family: var(--font-mono);
  font-size: 0.875em;
}

code {
  background: var(--paper-3);
  border: 1px solid var(--line);
  border-radius: 3px;
  padding: 1px 5px;
  color: var(--ink-900);
}

pre {
  background: var(--navy-950);
  color: #D8E1EC;
  border-radius: var(--radius);
  padding: 16px 18px;
  overflow-x: auto;
  line-height: 1.55;
  border: 1px solid var(--navy-800);
}

pre code { background: none; border: 0; padding: 0; color: inherit; }

/* --- Tata letak ---------------------------------------------------------- */

.wrap { max-width: var(--w); margin: 0 auto; padding: 0 24px; }

.bar {
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 40;
}

.bar-in {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 62px;
  gap: 24px;
}

.brand { display: flex; align-items: center; gap: 10px; border: 0; }
.brand:hover { border: 0; }

.brand-mark {
  width: 30px; height: 30px;
  background: var(--navy-900);
  border-radius: 4px;
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 700; font-size: 14px;
  position: relative;
}
.brand-mark::after {
  content: ''; position: absolute; left: 50%; bottom: 4px;
  transform: translateX(-50%); width: 12px; height: 1px;
  background: var(--copper-500);
}

.brand-name { font-weight: 700; color: var(--ink-900); font-size: 15.5px; letter-spacing: -0.02em; }

nav.main { display: flex; align-items: center; gap: 4px; }
nav.main a {
  border: 0; padding: 7px 11px; border-radius: 4px;
  color: var(--ink-500); font-size: 13.5px; font-weight: 500;
}
nav.main a:hover { background: var(--paper-3); color: var(--ink-900); border: 0; }
nav.main a.on { color: var(--ink-900); font-weight: 600; background: var(--paper-3); }

.bar-cta { display: flex; align-items: center; gap: 8px; }

/* --- Tombol -------------------------------------------------------------- */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  height: 36px; padding: 0 15px;
  border-radius: var(--radius);
  font-size: 13.5px; font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background-color .12s, border-color .12s, color .12s;
  font-family: inherit;
}
.btn-primary { background: var(--navy-900); color: #fff; border-color: var(--navy-950); }
.btn-primary:hover { background: var(--navy-800); }
.btn-outline { background: var(--paper); color: var(--ink-900); border-color: var(--line-strong); }
.btn-outline:hover { border-color: var(--navy-500); color: var(--navy-700); }
.btn-quiet { background: transparent; color: var(--ink-500); }
.btn-quiet:hover { background: var(--paper-3); color: var(--ink-900); }
.btn-lg { height: 42px; padding: 0 20px; font-size: 14px; }

/* --- Kepala halaman ------------------------------------------------------ */

.hero { border-bottom: 1px solid var(--line); background: var(--paper-2); }
.hero-in { padding: 58px 0 54px; display: grid; grid-template-columns: 1.15fr .85fr; gap: 48px; align-items: start; }

.eyebrow {
  font-size: 11px; font-weight: 700; letter-spacing: .14em;
  text-transform: uppercase; color: var(--copper-700); margin-bottom: 14px;
}

.hero h1 { font-size: 38px; margin-bottom: 16px; }
.hero .lead { font-size: 16.5px; color: var(--ink-500); max-width: 54ch; }
.hero-actions { display: flex; gap: 10px; margin-top: 26px; flex-wrap: wrap; }

.hero-note { font-size: 12.5px; color: var(--ink-400); margin-top: 16px; }

/* Kartu ringkas di sisi kanan hero */
.spec {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--paper); overflow: hidden; box-shadow: var(--shadow-sm);
}
.spec-h {
  padding: 11px 16px; border-bottom: 1px solid var(--line);
  font-size: 11px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase;
  color: var(--ink-400); background: var(--paper-3);
}
.spec-row {
  display: flex; justify-content: space-between; gap: 16px;
  padding: 11px 16px; border-bottom: 1px solid var(--line); font-size: 13px;
}
.spec-row:last-child { border-bottom: 0; }
.spec-row span:first-child { color: var(--ink-400); }
.spec-row span:last-child { color: var(--ink-900); font-weight: 600; font-family: var(--font-mono); font-size: 12.5px; }

/* --- Bagian -------------------------------------------------------------- */

section { padding: 52px 0; }
section + section { border-top: 1px solid var(--line); }
section.tight { padding: 38px 0; }

.sec-head { max-width: 66ch; margin-bottom: 30px; }
.sec-head h2 { margin-top: 0; }
.sec-head p { color: var(--ink-500); margin-bottom: 0; }

.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }

.card {
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px; background: var(--paper);
}
.card h3 { margin-top: 0; font-size: 15.5px; }
.card p { margin-bottom: 0; color: var(--ink-500); font-size: 13.5px; }
.card-num {
  font-family: var(--font-mono); font-size: 11.5px; font-weight: 700;
  color: var(--copper-700); letter-spacing: .08em; margin-bottom: 9px;
}

.card-hover:hover { border-color: var(--line-strong); box-shadow: var(--shadow-md); }

/* --- Tabel --------------------------------------------------------------- */

table { width: 100%; border-collapse: collapse; font-size: 13.5px; margin: 0 0 1em; }
th, td { border: 1px solid var(--line); padding: 10px 13px; text-align: left; vertical-align: top; }
th { background: var(--paper-3); font-size: 11.5px; text-transform: uppercase; letter-spacing: .08em; color: var(--ink-500); font-weight: 700; }
td code { font-size: 12.5px; }

/* --- Daftar -------------------------------------------------------------- */

ul.checks { list-style: none; padding: 0; margin: 0 0 1em; }
ul.checks li { padding-left: 22px; position: relative; margin-bottom: 7px; font-size: 14px; }
ul.checks li::before {
  content: ''; position: absolute; left: 3px; top: 9px;
  width: 6px; height: 6px; border-radius: 1px; background: var(--copper-500);
}

/* --- Penanda ------------------------------------------------------------- */

.tag {
  display: inline-block; font-size: 10.5px; font-weight: 700;
  letter-spacing: .07em; text-transform: uppercase;
  padding: 2px 7px; border-radius: 3px; border: 1px solid transparent;
}
.tag-ok { background: var(--ok-100); color: var(--ok-700); border-color: #C6E2D3; }
.tag-warn { background: var(--warn-100); color: var(--warn-700); border-color: #EAD9AE; }
.tag-info { background: var(--copper-100); color: var(--copper-700); border-color: #E8D5B4; }
.tag-plain { background: var(--paper-3); color: var(--ink-500); border-color: var(--line); }

/* --- Halaman dalam (dokumentasi, blog, syarat) --------------------------- */

.doc { display: grid; grid-template-columns: 232px 1fr; gap: 44px; padding: 40px 0 60px; }

.doc-side { position: sticky; top: 86px; align-self: start; font-size: 13.5px; }
.doc-side h4 { font-size: 11px; letter-spacing: .12em; text-transform: uppercase; color: var(--ink-400); margin: 0 0 9px; }
.doc-side ul { list-style: none; margin: 0 0 22px; padding: 0; }
.doc-side li { margin-bottom: 5px; }
.doc-side a { border: 0; color: var(--ink-500); }
.doc-side a:hover { color: var(--navy-700); }
.doc-side a.on { color: var(--ink-900); font-weight: 600; }

.doc-body { min-width: 0; }
.doc-body h2:first-child { margin-top: 0; }
.doc-body h2 { padding-top: 6px; border-top: 1px solid var(--line); }
.doc-body h2:first-child { border-top: 0; }

.note {
  border-left: 3px solid var(--copper-500);
  background: var(--copper-100);
  padding: 13px 16px; border-radius: 0 var(--radius) var(--radius) 0;
  font-size: 13.5px; margin: 0 0 1.2em;
}
.note strong { color: var(--copper-700); }

/* --- Kelas --------------------------------------------------------------- */

.class-row {
  display: grid; grid-template-columns: 1fr 210px 150px 140px;
  gap: 20px; align-items: center;
  padding: 18px 0; border-bottom: 1px solid var(--line);
}
.class-row:first-of-type { border-top: 1px solid var(--line); }
.class-row h3 { margin: 0 0 4px; font-size: 15.5px; }
.class-row p { margin: 0; font-size: 13px; color: var(--ink-500); }
.class-meta { font-size: 12.5px; color: var(--ink-400); font-family: var(--font-mono); }

/* --- Blog ---------------------------------------------------------------- */

.post { padding: 22px 0; border-bottom: 1px solid var(--line); }
.post:first-of-type { border-top: 1px solid var(--line); }
.post time { font-size: 12px; color: var(--ink-400); font-family: var(--font-mono); }
.post h3 { margin: 5px 0 6px; font-size: 17px; }
.post p { margin: 0; color: var(--ink-500); font-size: 14px; }

/* --- Riwayat perubahan --------------------------------------------------- */

.rel { display: grid; grid-template-columns: 130px 1fr; gap: 24px; padding: 20px 0; border-bottom: 1px solid var(--line); }
.rel:first-of-type { border-top: 1px solid var(--line); }
.rel .ver { font-family: var(--font-mono); font-size: 13px; font-weight: 700; color: var(--ink-900); }
.rel .ver small { display: block; font-weight: 400; color: var(--ink-400); font-size: 11.5px; margin-top: 3px; }
.rel ul { margin: 0; padding-left: 18px; font-size: 13.5px; }
.rel li { margin-bottom: 4px; }

/* --- Kaki halaman -------------------------------------------------------- */

footer { border-top: 1px solid var(--line); background: var(--paper-2); padding: 44px 0 30px; margin-top: 8px; }
.foot-grid { display: grid; grid-template-columns: 1.4fr repeat(3, 1fr); gap: 34px; margin-bottom: 34px; }
.foot-grid h5 { font-size: 11px; letter-spacing: .12em; text-transform: uppercase; color: var(--ink-400); margin: 0 0 12px; }
.foot-grid ul { list-style: none; margin: 0; padding: 0; font-size: 13.5px; }
.foot-grid li { margin-bottom: 7px; }
.foot-grid a { border: 0; color: var(--ink-500); }
.foot-grid a:hover { color: var(--navy-700); }
.foot-bottom {
  border-top: 1px solid var(--line); padding-top: 20px;
  display: flex; justify-content: space-between; gap: 20px;
  font-size: 12.5px; color: var(--ink-400); flex-wrap: wrap;
}

/* --- Responsif ---------------------------------------------------------- */

@media (max-width: 980px) {
  .hero-in { grid-template-columns: 1fr; gap: 30px; }
  .grid-3, .grid-4 { grid-template-columns: 1fr 1fr; }
  .doc { grid-template-columns: 1fr; gap: 24px; }
  .doc-side { position: static; }
  .class-row { grid-template-columns: 1fr; gap: 8px; }
  .foot-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 640px) {
  h1 { font-size: 27px; }
  .hero h1 { font-size: 28px; }
  .grid-3, .grid-4, .grid-2 { grid-template-columns: 1fr; }
  nav.main { display: none; }
  .foot-grid { grid-template-columns: 1fr; }
}