/*
 * casus.css — единая дизайн-система CASUS
 * Палитра: Slate #1E2534 / Amber #E8960A / Light #F2F2F0 (только эти три)
 * Шрифты: IBM Plex Serif / IBM Plex Sans / IBM Plex Mono
 * Breakpoints: 375 / 768 / 1024 / 1440
 */

:root {
  /* === Палитра (раздел 1.5 ТЗ) === */
  --slate:     #1E2534;
  --slate2:    #252B3B;
  --slate3:    #2F3748;
  --amber:     #E8960A;
  --amber2:    #F4AA22;
  --amber3:    rgba(232, 150, 10, .12);
  --light:     #F2F2F0;
  --light2:    #E8E8E5;
  --text:      #1E2534;
  --muted:     #7A8094;
  --rule:      rgba(30, 37, 52, .1);
  --rule-dark: rgba(255, 255, 255, .08);
  --grid:      rgba(30, 37, 52, .04);

  /* === Spacing (раздел D.3 ТЗ) === */
  --inner-max:   1200px;
  --narrow-max:  740px;
  --gap-tight:   2px;
  --gap-std:     24px;
  --gap-wide:    48px;
  --gap-xl:      80px;
  --pad-desktop: 80px 48px;
  --pad-tablet:  64px 28px;
  --pad-mobile:  52px 20px;

  --nav-h: 60px;
}

* , *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'IBM Plex Sans', system-ui, -apple-system, Segoe UI, sans-serif;
  background: var(--light);
  color: var(--text);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img, svg { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; }

/* === Typography utilities === */
.mono {
  font-family: 'IBM Plex Mono', monospace;
  letter-spacing: .12em; text-transform: uppercase;
}
.serif { font-family: 'IBM Plex Serif', Georgia, serif; }

/* === NAV (раздел 2.2 ТЗ) === */
.casus-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 48px; height: var(--nav-h);
  background: rgba(242, 242, 240, .97);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--rule);
}
.casus-nav-logo {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 18px; font-weight: 500;
  letter-spacing: .08em; text-transform: uppercase;
  color: var(--slate);
}
.casus-nav-logo em { color: var(--amber); font-style: normal; }

.casus-nav-links {
  display: flex; gap: 32px; list-style: none;
  margin: 0; padding: 0;
}
.casus-nav-links a {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; letter-spacing: .12em;
  text-transform: uppercase; color: var(--muted);
  transition: color .2s;
}
.casus-nav-links a:hover,
.casus-nav-links a[aria-current="page"] { color: var(--text); }
.casus-nav-links a[aria-current="page"] { color: var(--amber); }

.casus-nav-cta {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--slate);
  background: transparent;
  border: 1px solid var(--slate);
  padding: 9px 20px;
  transition: background .2s, color .2s;
}
.casus-nav-cta:hover { background: var(--slate); color: var(--light); }

.casus-nav-burger {
  display: none;
  width: 32px; height: 32px;
  border: 1px solid var(--rule);
  background: transparent; cursor: pointer;
  position: relative;
}
.casus-nav-burger span,
.casus-nav-burger span::before,
.casus-nav-burger span::after {
  content: ''; position: absolute;
  left: 6px; right: 6px; height: 1.5px;
  background: var(--slate);
}
.casus-nav-burger span { top: 50%; transform: translateY(-50%); }
.casus-nav-burger span::before { top: -7px; }
.casus-nav-burger span::after  { top:  7px; }

/* === Buttons === */
.btn-primary {
  display: inline-block;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--light);
  background: var(--slate); border: none; cursor: pointer;
  padding: 14px 28px;
  transition: background .2s, transform .15s;
}
.btn-primary:hover { background: var(--amber); transform: translateY(-1px); }

.btn-amber {
  display: inline-block;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--slate);
  background: var(--amber); border: none; cursor: pointer;
  padding: 14px 28px;
  transition: background .2s;
}
.btn-amber:hover { background: var(--amber2); }

.btn-text {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--muted);
  transition: color .2s;
}
.btn-text:hover { color: var(--text); }

/* === Forms (общая стилизация для slate-блоков) === */
.casus-form { display: flex; flex-direction: column; gap: 16px; }
.casus-form-field { display: block; }
.casus-form-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px; letter-spacing: .15em;
  text-transform: uppercase; color: rgba(242, 242, 240, .4);
  display: block; margin-bottom: 8px;
}
.casus-form-input {
  width: 100%;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 15px; color: var(--light);
  background: rgba(255, 255, 255, .05);
  border: 1px solid rgba(255, 255, 255, .1);
  padding: 12px 16px; outline: none;
  transition: border-color .2s;
}
.casus-form-input:focus { border-color: var(--amber); }
.casus-form-input::placeholder { color: rgba(242, 242, 240, .25); }
textarea.casus-form-input { min-height: 120px; resize: vertical; font-family: inherit; }

.casus-form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

.casus-form-submit {
  width: 100%; margin-top: 8px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--slate); background: var(--amber);
  border: none; cursor: pointer; padding: 16px;
  transition: background .2s;
}
.casus-form-submit:hover:not(:disabled) { background: var(--amber2); }
.casus-form-submit:disabled { opacity: .6; cursor: wait; }

.casus-form-note {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px; letter-spacing: .08em;
  color: rgba(242, 242, 240, .25);
  margin-top: 12px; text-align: center;
}

/* Honeypot */
.casus-hp {
  position: absolute !important; left: -9999px !important;
  width: 1px !important; height: 1px !important; opacity: 0 !important;
}

/* === FOOTER (раздел 2.3 ТЗ) === */
.casus-footer {
  background: var(--slate2);
  padding: 60px 48px 40px;
  border-top: 2px solid var(--amber);
  color: rgba(242, 242, 240, .4);
}
.casus-footer-grid {
  display: grid; grid-template-columns: 280px 1fr 240px;
  gap: 60px; max-width: var(--inner-max);
  margin: 0 auto 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255, 255, 255, .06);
}
.casus-footer-brand {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 20px; font-weight: 500;
  letter-spacing: .1em; text-transform: uppercase;
  color: var(--light);
}
.casus-footer-brand em { color: var(--amber); font-style: normal; }
.casus-footer-tagline {
  font-size: 14px; line-height: 1.6; margin-top: 12px;
}
.casus-footer-nav { display: grid; grid-template-columns: repeat(3, 1fr); gap: 40px; }
.casus-footer-col-title {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px; letter-spacing: .2em;
  text-transform: uppercase; color: var(--amber);
  margin-bottom: 16px;
}
.casus-footer-col a {
  display: block; font-size: 14px;
  color: rgba(242, 242, 240, .4);
  margin-bottom: 8px; transition: color .2s;
}
.casus-footer-col a:hover { color: var(--light); }
.casus-footer-contacts {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; letter-spacing: .05em;
  line-height: 1.9;
}
.casus-footer-contacts a:hover { color: var(--amber); }
.casus-footer-bottom {
  max-width: var(--inner-max); margin: 0 auto;
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: 12px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px; letter-spacing: .08em;
  color: rgba(242, 242, 240, .3);
}
.casus-footer-bottom a:hover { color: var(--amber); }

/* === Page common === */
.casus-page { padding-top: var(--nav-h); }
.casus-section { padding: var(--pad-desktop); position: relative; }
.casus-section-inner { max-width: var(--inner-max); margin: 0 auto; position: relative; }

.casus-eyebrow {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px; letter-spacing: .2em;
  text-transform: uppercase; color: var(--amber);
  margin-bottom: 16px;
}
.casus-h1 {
  font-family: 'IBM Plex Serif', serif;
  font-size: clamp(40px, 5vw, 68px);
  font-weight: 600; line-height: 1.1; color: var(--slate);
}
.casus-h1 em { font-style: italic; color: var(--amber); }
.casus-h2 {
  font-family: 'IBM Plex Serif', serif;
  font-size: clamp(32px, 4vw, 52px);
  font-weight: 600; line-height: 1.15; color: var(--slate);
}
.casus-h2 em { font-style: italic; color: var(--amber); }
.casus-h3 {
  font-family: 'IBM Plex Serif', serif;
  font-size: clamp(22px, 2.4vw, 28px);
  font-weight: 600; line-height: 1.25; color: var(--slate);
}
.casus-lead {
  font-size: 18px; line-height: 1.7; color: var(--muted);
  max-width: 720px;
}

/* Background grid (как на главной) */
.casus-grid-bg::before {
  content: ''; position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}

/* === Breadcrumbs === */
.casus-breadcrumb {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px; letter-spacing: .15em;
  text-transform: uppercase; color: var(--muted);
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
  margin-bottom: 24px;
}
.casus-breadcrumb a:hover { color: var(--amber); }
.casus-breadcrumb span[aria-current] { color: var(--text); }

/* === Breakpoints (раздел D ТЗ) === */
@media (max-width: 1024px) {
  .casus-section { padding: var(--pad-tablet); }
  .casus-footer { padding: 60px 28px 32px; }
  .casus-footer-grid { grid-template-columns: 1fr 1fr; gap: 40px; }
  .casus-footer-contacts { grid-column: 1 / -1; }
  .casus-footer-nav { grid-column: 1 / -1; }
}
@media (max-width: 768px) {
  .casus-nav { padding: 0 20px; }
  .casus-nav-links { display: none; }
  .casus-nav-burger { display: block; }
  .casus-nav.is-open .casus-nav-links {
    display: flex; flex-direction: column; gap: 0;
    position: absolute; top: var(--nav-h); left: 0; right: 0;
    background: var(--light); padding: 16px 20px;
    border-bottom: 1px solid var(--rule);
  }
  .casus-nav.is-open .casus-nav-links a {
    padding: 14px 0;
    border-bottom: 1px solid var(--rule);
  }
  .casus-form-grid { grid-template-columns: 1fr; }
  .casus-footer { padding: 48px 20px 28px; }
  .casus-footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .casus-footer-nav { grid-template-columns: 1fr 1fr; gap: 24px; }
  .casus-footer-bottom { flex-direction: column; align-items: flex-start; }
}
@media (max-width: 375px) {
  .casus-section { padding: var(--pad-mobile); }
  .casus-h1 { font-size: clamp(28px, 7vw, 40px); }
  .casus-h2 { font-size: clamp(24px, 6vw, 32px); }
}