/*
  CostIntel main.css
  Core design system for CostIntel.co.uk
  Covers: base styles, typography, layout, header, footer, cards, grids, buttons, forms, accessibility, and responsive behaviour.
*/

/* =========================
   1. Design Tokens
========================= */

:root {
  /* Brand colours */
  --ci-ink: #0f172a;
  --ci-ink-soft: #1e293b;
  --ci-slate: #334155;
  --ci-muted: #475569;
  --ci-muted-light: #64748b;
  --ci-line: #e2e8f0;
  --ci-line-strong: #cbd5e1;
  --ci-bg: #f8fafc;
  --ci-surface: #ffffff;
  --ci-surface-soft: #f1f5f9;

  --ci-primary: #0ea5a4;
  --ci-primary-dark: #0f766e;
  --ci-primary-soft: #ccfbf1;

  --ci-accent: #f59e0b;
  --ci-accent-soft: #fef3c7;

  --ci-danger: #b91c1c;
  --ci-success: #15803d;

  /* Typography */
  --ci-font: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  --ci-text-xs: 0.78rem;
  --ci-text-sm: 0.88rem;
  --ci-text-base: 1rem;
  --ci-text-md: 1.08rem;
  --ci-text-lg: 1.25rem;
  --ci-text-xl: 1.55rem;
  --ci-text-2xl: 2rem;
  --ci-text-3xl: clamp(2rem, 5vw, 3rem);

  --ci-leading-tight: 1.15;
  --ci-leading-normal: 1.6;
  --ci-leading-relaxed: 1.75;

  /* Spacing */
  --ci-space-1: 0.375rem;
  --ci-space-2: 0.625rem;
  --ci-space-3: 0.875rem;
  --ci-space-4: 1.125rem;
  --ci-space-5: 1.5rem;
  --ci-space-6: 2rem;
  --ci-space-7: 2.75rem;
  --ci-space-8: 4rem;
  --ci-space-9: 5.5rem;

  /* Layout */
  --ci-container: 1120px;
  --ci-container-wide: 1280px;
  --ci-header-height: 64px;

  /* Radius */
  --ci-radius-xs: 0.35rem;
  --ci-radius-sm: 0.5rem;
  --ci-radius-md: 0.75rem;
  --ci-radius-lg: 1rem;
  --ci-radius-xl: 1.4rem;
  --ci-radius-pill: 999px;

  /* Shadows */
  --ci-shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --ci-shadow-md: 0 1px 0 rgba(15, 23, 42, 0.04), 0 10px 24px rgba(15, 23, 42, 0.055);
  --ci-shadow-lg: 0 16px 40px rgba(15, 23, 42, 0.08);

  /* Motion */
  --ci-transition: 180ms ease;
}

/* =========================
   2. Base Reset
========================= */

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--ci-font);
  font-size: var(--ci-text-base);
  line-height: var(--ci-leading-normal);
  color: var(--ci-ink);
  background: var(--ci-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img,
svg,
video,
canvas {
  max-width: 100%;
  height: auto;
}

button,
input,
select,
textarea {
  font: inherit;
}

a {
  color: inherit;
}

p,
h1,
h2,
h3,
h4,
h5,
h6 {
  overflow-wrap: break-word;
}

::selection {
  background: var(--ci-primary-soft);
  color: var(--ci-ink);
}

/* =========================
   3. Typography
========================= */

h1,
h2,
h3,
h4 {
  margin: 0;
  color: var(--ci-ink);
  letter-spacing: -0.025em;
}

h1 {
  font-size: var(--ci-text-3xl);
  line-height: var(--ci-leading-tight);
  font-weight: 700;
}

h2 {
  font-size: var(--ci-text-2xl);
  line-height: 1.25;
  font-weight: 700;
}

h3 {
  font-size: var(--ci-text-lg);
  line-height: 1.3;
  font-weight: 650;
}

h4 {
  font-size: var(--ci-text-base);
  line-height: 1.35;
  font-weight: 650;
}

p {
  margin: 0;
  color: var(--ci-muted);
}

.ci-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--ci-space-2);
  color: var(--ci-primary-dark);
  background: var(--ci-primary-soft);
  border-radius: var(--ci-radius-pill);
  padding: 0.35rem 0.7rem;
  font-size: var(--ci-text-xs);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.ci-lede {
  font-size: var(--ci-text-md);
  line-height: var(--ci-leading-relaxed);
  color: var(--ci-muted);
  max-width: 720px;
}

.ci-small {
  font-size: var(--ci-text-sm);
  color: var(--ci-muted-light);
}

.ci-number {
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.015em;
}

/* =========================
   4. Layout Utilities
========================= */

.ci-container {
  width: min(100% - 2rem, var(--ci-container));
  margin-inline: auto;
}

.ci-container-wide {
  width: min(100% - 2rem, var(--ci-container-wide));
  margin-inline: auto;
}

.ci-section {
  padding-block: var(--ci-space-8);
}

.ci-section-tight {
  padding-block: var(--ci-space-6);
}

.ci-section-header {
  display: grid;
  gap: var(--ci-space-3);
  margin-bottom: var(--ci-space-6);
  max-width: 760px;
}

.ci-stack-sm {
  display: grid;
  gap: var(--ci-space-2);
}

.ci-stack {
  display: grid;
  gap: var(--ci-space-4);
}

.ci-stack-lg {
  display: grid;
  gap: var(--ci-space-6);
}

.ci-split {
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(280px, 0.88fr);
  gap: var(--ci-space-7);
  align-items: center;
}

.ci-grid {
  display: grid;
  gap: var(--ci-space-5);
}

.ci-grid-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.ci-grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.ci-grid-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

/* =========================
   5. Buttons and Links
========================= */

.ci-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  min-height: 42px;
  padding: 0.7rem 1rem;
  border-radius: var(--ci-radius-sm);
  border: 1px solid transparent;
  font-size: var(--ci-text-sm);
  font-weight: 650;
  line-height: 1;
  text-decoration: none;
  cursor: pointer;
  transition: background var(--ci-transition), border-color var(--ci-transition), color var(--ci-transition), transform var(--ci-transition);
}

.ci-button:hover {
  transform: translateY(-1px);
}

.ci-button-primary {
  background: var(--ci-primary);
  color: #fff;
}

.ci-button-primary:hover {
  background: var(--ci-primary-dark);
}

.ci-button-secondary {
  background: var(--ci-surface);
  color: var(--ci-ink);
  border-color: var(--ci-line);
}

.ci-button-secondary:hover {
  border-color: var(--ci-line-strong);
}

.ci-text-link {
  color: var(--ci-primary-dark);
  font-weight: 650;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

.ci-chip-link {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--ci-line);
  border-radius: var(--ci-radius-pill);
  padding: 0.4rem 0.7rem;
  color: var(--ci-slate);
  background: var(--ci-surface);
  text-decoration: none;
  font-size: var(--ci-text-sm);
  transition: border-color var(--ci-transition), color var(--ci-transition);
}

.ci-chip-link:hover {
  border-color: var(--ci-primary);
  color: var(--ci-primary-dark);
}

/* =========================
   6. Header
========================= */

.ci-site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--ci-line);
  backdrop-filter: blur(12px);
}

.ci-nav {
  min-height: var(--ci-header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--ci-space-5);
}

.ci-logo {
  display: inline-flex;
  align-items: center;
  gap: var(--ci-space-2);
  text-decoration: none;
}

.ci-logo-img {
  height: 36px;
  width: auto;
  display: block;
  transition: transform var(--ci-transition);
}

.ci-logo:hover .ci-logo-img {
  transform: translateY(-1px);
}

/* Optional fallback mark if no image logo is used */
.ci-logo-mark {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: 0.65rem;
  background: var(--ci-ink);
  color: var(--ci-accent);
  font-weight: 800;
  font-size: 0.88rem;
}

.ci-nav-links {
  display: flex;
  align-items: center;
  gap: var(--ci-space-4);
}

.ci-nav-links a {
  color: var(--ci-slate);
  font-size: var(--ci-text-sm);
  text-decoration: none;
  font-weight: 550;
}

.ci-nav-links a:hover {
  color: var(--ci-ink);
}

/* =========================
   7. Cards
========================= */

.ci-card {
  display: block;
  background: var(--ci-surface);
  border: 1px solid var(--ci-line);
  border-radius: var(--ci-radius-md);
  padding: var(--ci-space-5);
  box-shadow: var(--ci-shadow-sm);
  text-decoration: none;
  transition: border-color var(--ci-transition), box-shadow var(--ci-transition), transform var(--ci-transition);
}

.ci-card:hover {
  border-color: var(--ci-primary);
  box-shadow: var(--ci-shadow-md);
  transform: translateY(-2px);
}

.ci-card h3,
.ci-card h4 {
  margin-bottom: var(--ci-space-2);
}

.ci-card p {
  font-size: var(--ci-text-sm);
}

.ci-card-meta {
  margin-top: var(--ci-space-4);
  color: var(--ci-slate);
  font-size: var(--ci-text-sm);
  font-weight: 650;
  font-variant-numeric: tabular-nums;
}

.ci-card-muted {
  background: var(--ci-surface-soft);
}

/* =========================
   8. Forms and Search
========================= */

.ci-search {
  display: flex;
  gap: var(--ci-space-2);
  width: 100%;
  max-width: 660px;
}

.ci-input,
.ci-select,
.ci-textarea {
  width: 100%;
  border: 1px solid var(--ci-line);
  border-radius: var(--ci-radius-md);
  background: var(--ci-surface);
  color: var(--ci-ink);
  padding: 0.9rem 1rem;
  outline: none;
  transition: border-color var(--ci-transition), box-shadow var(--ci-transition);
}

.ci-input:focus,
.ci-select:focus,
.ci-textarea:focus {
  border-color: var(--ci-primary);
  box-shadow: 0 0 0 4px rgba(14, 165, 164, 0.12);
}

.ci-input::placeholder {
  color: #94a3b8;
}

/* =========================
   9. Data and Panels
========================= */

.ci-panel {
  background: var(--ci-surface);
  border: 1px solid var(--ci-line);
  border-radius: var(--ci-radius-lg);
  padding: var(--ci-space-5);
  box-shadow: var(--ci-shadow-md);
}

.ci-panel-title {
  margin-bottom: var(--ci-space-4);
  color: var(--ci-slate);
  font-size: var(--ci-text-sm);
  font-weight: 700;
}

.ci-metric-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--ci-space-4);
  padding-block: 0.55rem;
  border-bottom: 1px solid var(--ci-line);
  font-size: var(--ci-text-sm);
}

.ci-metric-row:last-child {
  border-bottom: 0;
}

.ci-metric-row strong {
  font-variant-numeric: tabular-nums;
  color: var(--ci-ink);
}

.ci-data-strip {
  background: var(--ci-ink);
  color: #fff;
  padding-block: var(--ci-space-5);
}

.ci-data-strip-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--ci-space-4) var(--ci-space-6);
  font-size: var(--ci-text-sm);
}

.ci-data-strip strong {
  color: var(--ci-accent);
  font-variant-numeric: tabular-nums;
}

/* =========================
   10. Footer
========================= */

.ci-site-footer {
  background: var(--ci-ink);
  color: #cbd5e1;
  padding-block: var(--ci-space-8);
}

.ci-footer-grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(3, 1fr);
  gap: var(--ci-space-6);
}

.ci-site-footer h4 {
  color: #fff;
  margin-bottom: var(--ci-space-3);
  font-size: var(--ci-text-sm);
}

.ci-site-footer p,
.ci-site-footer a {
  color: #cbd5e1;
  font-size: var(--ci-text-sm);
}

.ci-site-footer a {
  display: block;
  margin-block: 0.35rem;
  text-decoration: none;
}

.ci-site-footer a:hover {
  color: #fff;
}

.ci-site-footer .ci-logo {
  margin-bottom: var(--ci-space-3);
}

.ci-site-footer .ci-logo-img {
  height: 34px;
}

/* =========================
   11. Accessibility
========================= */

.skip-link {
  position: absolute;
  left: 1rem;
  top: -100px;
  z-index: 100;
  background: var(--ci-ink);
  color: #fff;
  padding: 0.7rem 1rem;
  border-radius: var(--ci-radius-sm);
}

.skip-link:focus {
  top: 1rem;
}

:focus-visible {
  outline: 3px solid rgba(14, 165, 164, 0.45);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.001ms !important;
  }
}

/* =========================
   12. Responsive Rules
========================= */

@media (max-width: 980px) {
  .ci-split {
    grid-template-columns: 1fr;
  }

  .ci-grid-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .ci-grid-3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .ci-footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  :root {
    --ci-header-height: 58px;
    --ci-space-8: 3rem;
    --ci-space-9: 4rem;
  }

  .ci-nav-links {
    display: none;
  }

  .ci-search {
    flex-direction: column;
  }

  .ci-grid-2,
  .ci-grid-3,
  .ci-grid-4 {
    grid-template-columns: 1fr;
  }

  .ci-section-header {
    margin-bottom: var(--ci-space-5);
  }
}

@media (max-width: 520px) {
  .ci-container,
  .ci-container-wide {
    width: min(100% - 1.25rem, var(--ci-container));
  }

  .ci-nav {
    gap: var(--ci-space-3);
  }

  .ci-logo-img {
    height: 30px;
  }

  .ci-logo-mark {
    width: 30px;
    height: 30px;
  }

  .ci-button {
    min-height: 40px;
    padding-inline: 0.85rem;
  }

  .ci-footer-grid {
    grid-template-columns: 1fr;
  }
}