/* ========================================
   STRATUM ASSET INTELLIGENCE — Design System
   ======================================== */

/* --- Type Scale (Fluid) --- */
:root {
  --text-xs:   clamp(0.75rem,  0.7rem  + 0.25vw, 0.875rem);
  --text-sm:   clamp(0.875rem, 0.8rem  + 0.35vw, 1rem);
  --text-base: clamp(1rem,     0.95rem + 0.25vw, 1.125rem);
  --text-lg:   clamp(1.125rem, 1rem    + 0.75vw, 1.5rem);
  --text-xl:   clamp(1.5rem,   1.2rem  + 1.25vw, 2.25rem);
  --text-2xl:  clamp(2rem,     1.2rem  + 2.5vw,  3.5rem);
  --text-3xl:  clamp(2.5rem,   1rem    + 4vw,    5rem);

  /* --- Spacing (4px base) --- */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* --- Fonts --- */
  --font-display: 'General Sans', 'Helvetica Neue', sans-serif;
  --font-body: 'Satoshi', 'Inter', sans-serif;

  /* --- Radius --- */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* --- Transitions --- */
  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);

  /* --- Content Widths --- */
  --content-narrow: 640px;
  --content-default: 960px;
  --content-wide: 1200px;
  --content-full: 100%;
}

/* --- Stratum Brand Palette (Dark-First) --- */
:root, [data-theme="dark"] {
  /* Surfaces — Deep navy from brand */
  --color-bg:             #0f1729;
  --color-surface:        #151e35;
  --color-surface-2:      #1a2540;
  --color-surface-offset: #1e2a48;
  --color-border:         #2a3756;
  --color-divider:        #232f4d;

  /* Text */
  --color-text:           #e8eaf0;
  --color-text-muted:     #8b93a8;
  --color-text-faint:     #5a6380;
  --color-text-inverse:   #0f1729;

  /* Primary Accent — Stratum Cyan/Teal from logo */
  --color-primary:        #3bb5e0;
  --color-primary-hover:  #2d9cc4;
  --color-primary-active: #1f80a5;
  --color-primary-light:  rgba(59, 181, 224, 0.12);

  /* Secondary — White accent for layered CTAs */
  --color-secondary:      #ffffff;
  --color-secondary-hover:#e8eaf0;

  /* Success / Warning / Error */
  --color-success:        #6daa45;
  --color-warning:        #e8a534;
  --color-error:          #d16370;

  /* Shadows */
  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.2);
  --shadow-md: 0 4px 12px oklch(0 0 0 / 0.3);
  --shadow-lg: 0 12px 32px oklch(0 0 0 / 0.4);
}

[data-theme="light"] {
  --color-bg:             #f4f6f9;
  --color-surface:        #ffffff;
  --color-surface-2:      #f8f9fb;
  --color-surface-offset: #edf0f5;
  --color-border:         #d1d7e2;
  --color-divider:        #dde2eb;

  --color-text:           #0f1729;
  --color-text-muted:     #5a6380;
  --color-text-faint:     #8b93a8;
  --color-text-inverse:   #f4f6f9;

  --color-primary:        #1a7fa5;
  --color-primary-hover:  #156a8c;
  --color-primary-active: #0f5573;
  --color-primary-light:  rgba(26, 127, 165, 0.1);

  --color-secondary:      #0f1729;
  --color-secondary-hover:#232f4d;

  --color-success:        #437a22;
  --color-warning:        #b07a00;
  --color-error:          #a13544;

  --shadow-sm: 0 1px 2px oklch(0.2 0.01 80 / 0.06);
  --shadow-md: 0 4px 12px oklch(0.2 0.01 80 / 0.08);
  --shadow-lg: 0 12px 32px oklch(0.2 0.01 80 / 0.12);
}

/* --- System pref dark fallback --- */
@media (prefers-color-scheme: light) {
  :root:not([data-theme]) {
    --color-bg:             #f4f6f9;
    --color-surface:        #ffffff;
    --color-surface-2:      #f8f9fb;
    --color-surface-offset: #edf0f5;
    --color-border:         #d1d7e2;
    --color-divider:        #dde2eb;
    --color-text:           #0f1729;
    --color-text-muted:     #5a6380;
    --color-text-faint:     #8b93a8;
    --color-text-inverse:   #f4f6f9;
    --color-primary:        #1a7fa5;
    --color-primary-hover:  #156a8c;
    --color-primary-active: #0f5573;
    --color-primary-light:  rgba(26, 127, 165, 0.1);
    --color-secondary:      #0f1729;
    --color-secondary-hover:#232f4d;
    --color-success:        #437a22;
    --color-warning:        #b07a00;
    --color-error:          #a13544;
    --shadow-sm: 0 1px 2px oklch(0.2 0.01 80 / 0.06);
    --shadow-md: 0 4px 12px oklch(0.2 0.01 80 / 0.08);
    --shadow-lg: 0 12px 32px oklch(0.2 0.01 80 / 0.12);
  }
}

/* ========================================
   GLOBAL COMPONENTS
   ======================================== */

/* --- Container --- */
.container {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--space-4);
}

@media (min-width: 768px) {
  .container { padding-inline: var(--space-8); }
}

/* --- Section Spacing --- */
.section {
  padding-block: clamp(var(--space-12), 8vw, var(--space-24));
}

/* --- Typography --- */
.font-display { font-family: var(--font-display); }

h1 { font-family: var(--font-display); font-size: var(--text-2xl); font-weight: 600; letter-spacing: -0.02em; }
h2 { font-family: var(--font-display); font-size: var(--text-xl); font-weight: 600; letter-spacing: -0.01em; }
h3 { font-size: var(--text-lg); font-weight: 600; }
h4 { font-size: var(--text-base); font-weight: 600; }

.overline {
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-primary);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--radius-md);
  text-decoration: none;
  cursor: pointer;
  transition: background var(--transition-interactive),
              color var(--transition-interactive),
              transform var(--transition-interactive),
              box-shadow var(--transition-interactive);
}

.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn-primary {
  background: var(--color-primary);
  color: #ffffff;
}
.btn-primary:hover {
  background: var(--color-primary-hover);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}
.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
}

/* --- Cards --- */
.card {
  background: var(--color-surface);
  border: 1px solid oklch(from var(--color-text) l c h / 0.08);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: box-shadow var(--transition-interactive),
              transform var(--transition-interactive),
              border-color var(--transition-interactive);
}

.card:hover {
  box-shadow: var(--shadow-md);
  border-color: oklch(from var(--color-primary) l c h / 0.25);
}

/* --- Header / Navigation --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: oklch(from var(--color-bg) l c h / 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-divider);
  transition: transform 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out);
}

.site-header--scrolled { box-shadow: var(--shadow-sm); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

/* --- Header Brand Text Lockup --- */
.header-brand {
  display: flex;
  flex-direction: column;
  justify-content: center;
  text-decoration: none;
  color: inherit;
  line-height: 1.3;
  flex-shrink: 0;
}

.header-brand-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-text);
}

.header-brand-tagline {
  font-size: 0.7rem;
  color: var(--color-text-faint);
  letter-spacing: 0.01em;
}

@media (min-width: 768px) {
  .header-brand-name {
    font-size: 0.9rem;
  }
  .header-brand-tagline {
    font-size: 0.75rem;
  }
}

.nav-desktop {
  display: none;
  align-items: center;
  gap: var(--space-1);
}

@media (min-width: 900px) {
  .nav-desktop { display: flex; }
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  transition: color var(--transition-interactive), background var(--transition-interactive);
}

.nav-link:hover, .nav-link.active {
  color: var(--color-text);
  background: var(--color-primary-light);
}

.nav-link.active {
  color: var(--color-primary);
}

.nav-cta {
  margin-left: var(--space-2);
}

/* Mobile nav button */
.mobile-menu-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  color: var(--color-text);
}

@media (min-width: 900px) {
  .mobile-menu-btn { display: none; }
}

/* Mobile nav panel */
.mobile-nav {
  display: none;
  position: fixed;
  inset: 72px 0 0 0;
  background: var(--color-bg);
  padding: var(--space-6) var(--space-4);
  z-index: 49;
  flex-direction: column;
  gap: var(--space-2);
  overflow-y: auto;
}

.mobile-nav.open { display: flex; }

.mobile-nav .nav-link {
  font-size: var(--text-base);
  padding: var(--space-3) var(--space-4);
  display: block;
}

.mobile-nav .btn {
  margin-top: var(--space-4);
  text-align: center;
  justify-content: center;
}

/* --- Theme Toggle --- */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  transition: color var(--transition-interactive), background var(--transition-interactive);
}

.theme-toggle:hover {
  color: var(--color-text);
  background: var(--color-primary-light);
}

/* --- Footer --- */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-divider);
  padding-block: var(--space-12) var(--space-6);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
  margin-bottom: var(--space-8);
}

@media (min-width: 640px) {
  .footer-grid { grid-template-columns: 2fr 1fr 1fr; }
}

@media (min-width: 900px) {
  .footer-grid { grid-template-columns: 2fr 1fr 1fr 1fr; }
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.footer-brand-name {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--color-text);
}

.footer-brand-tagline {
  font-size: var(--text-sm);
  color: var(--color-text-faint);
}

.footer-brand p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  margin-top: var(--space-3);
  max-width: 32ch;
}

.footer-col h4 {
  font-size: var(--text-sm);
  font-weight: 600;
  margin-bottom: var(--space-3);
  color: var(--color-text);
}

.footer-col a {
  display: block;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  padding-block: var(--space-1);
  transition: color var(--transition-interactive);
}

.footer-col a:hover {
  color: var(--color-primary);
}

.footer-bottom {
  border-top: 1px solid var(--color-divider);
  padding-top: var(--space-6);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

.footer-bottom a {
  color: var(--color-text-faint);
  text-decoration: none;
  transition: color var(--transition-interactive);
}
.footer-bottom a:hover { color: var(--color-primary); }

/* ========================================
   PAGE-SPECIFIC STYLES
   ======================================== */

/* --- Hero Section --- */
.hero {
  position: relative;
  padding-block: clamp(var(--space-16), 12vw, var(--space-32));
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.hero-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.3;
}

.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    oklch(from var(--color-bg) l c h / 0.4) 0%,
    oklch(from var(--color-bg) l c h / 0.85) 50%,
    var(--color-bg) 100%
  );
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 720px;
}

.hero h1 {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-4);
}

.hero p {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
  max-width: 56ch;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

/* --- Stats Bar --- */
.stats-bar {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
  padding-block: var(--space-8);
}

@media (min-width: 768px) {
  .stats-bar { grid-template-columns: repeat(4, 1fr); }
}

.stat-item {
  text-align: center;
}

.stat-value {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-primary);
}

.stat-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}

/* --- Feature / Service Grid --- */
.feature-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

@media (min-width: 640px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .feature-grid--3 { grid-template-columns: repeat(3, 1fr); }
}

.feature-card .feature-icon {
  width: 48px;
  height: 48px;
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

.feature-card h3 {
  margin-bottom: var(--space-2);
}

.feature-card p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

/* --- Section Header --- */
.section-header {
  margin-bottom: var(--space-10);
}

.section-header .overline {
  margin-bottom: var(--space-2);
}

.section-header h2 {
  margin-bottom: var(--space-3);
}

.section-header p {
  color: var(--color-text-muted);
  max-width: 56ch;
}

/* --- Two Col Layout --- */
.two-col {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
  align-items: center;
}

@media (min-width: 768px) {
  .two-col { grid-template-columns: 1fr 1fr; }
}

.two-col-img {
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.two-col-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* --- CTA Banner --- */
.cta-banner {
  background: linear-gradient(135deg, var(--color-surface-offset) 0%, var(--color-surface) 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-10) var(--space-8);
  text-align: center;
}

.cta-banner h2 { margin-bottom: var(--space-3); }
.cta-banner p {
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
  margin-inline: auto;
}

/* --- Process Steps --- */
.process-steps {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
  counter-reset: step;
}

@media (min-width: 768px) {
  .process-steps { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .process-steps { grid-template-columns: repeat(4, 1fr); }
}

.process-step {
  counter-increment: step;
  position: relative;
}

.step-number {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-primary);
  opacity: 0.3;
  margin-bottom: var(--space-3);
}

.process-step h3 { margin-bottom: var(--space-2); }
.process-step p { color: var(--color-text-muted); font-size: var(--text-sm); }

/* --- Industry Cards --- */
.industry-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.industry-card .industry-icon {
  width: 40px;
  height: 40px;
  color: var(--color-primary);
}

.industry-card h3 { font-size: var(--text-base); }

.industry-card ul {
  list-style: none;
  padding: 0;
}

.industry-card ul li {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding-block: var(--space-1);
  padding-left: var(--space-4);
  position: relative;
}

.industry-card ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 6px;
  height: 6px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  opacity: 0.5;
}

/* --- Contact Form --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
}

@media (min-width: 768px) {
  .contact-grid { grid-template-columns: 1fr 1fr; }
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.form-group label {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text);
}

.form-group input,
.form-group textarea,
.form-group select {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-base);
  color: var(--color-text);
  transition: border-color var(--transition-interactive),
              box-shadow var(--transition-interactive);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.contact-info-card {
  background: var(--color-surface);
  border: 1px solid oklch(from var(--color-text) l c h / 0.08);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

.contact-info-item {
  display: flex;
  gap: var(--space-3);
  padding-block: var(--space-3);
}

.contact-info-item + .contact-info-item {
  border-top: 1px solid var(--color-divider);
}

.contact-info-item svg {
  width: 20px;
  height: 20px;
  color: var(--color-primary);
  flex-shrink: 0;
  margin-top: 2px;
}

.contact-info-item h4 {
  font-size: var(--text-sm);
  margin-bottom: var(--space-1);
}

.contact-info-item p,
.contact-info-item a {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
}

.contact-info-item a:hover { color: var(--color-primary); }

/* --- Page Header (interior pages) --- */
.page-header {
  padding-block: clamp(var(--space-10), 8vw, var(--space-20));
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-divider);
}

.page-header .overline { margin-bottom: var(--space-2); }
.page-header h1 { margin-bottom: var(--space-3); }
.page-header p {
  color: var(--color-text-muted);
  max-width: 56ch;
}

/* --- Resource Shell --- */
.resource-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

@media (min-width: 640px) {
  .resource-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .resource-grid { grid-template-columns: repeat(3, 1fr); }
}

.resource-card {
  display: flex;
  flex-direction: column;
}

.resource-card .resource-tag {
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: var(--space-2);
}

.resource-card h3 {
  font-size: var(--text-base);
  margin-bottom: var(--space-2);
}

.resource-card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  flex: 1;
}

.resource-card .resource-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-primary);
  text-decoration: none;
  margin-top: var(--space-3);
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}

.resource-card .resource-link:hover {
  text-decoration: underline;
}

/* --- Why Stratum Differentiators --- */
.diff-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

@media (min-width: 768px) {
  .diff-grid { grid-template-columns: repeat(2, 1fr); }
}

.diff-card {
  display: flex;
  gap: var(--space-4);
}

.diff-number {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-primary);
  opacity: 0.25;
  flex-shrink: 0;
  line-height: 1;
}

.diff-card h3 {
  font-size: var(--text-base);
  margin-bottom: var(--space-2);
}

.diff-card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

/* --- Scroll Reveal (IntersectionObserver-based) --- */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .fade-in {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* --- Comparison Table --- */
.comparison-table {
  overflow-x: auto;
}

.comparison-table table {
  min-width: 600px;
  font-size: var(--text-sm);
}

.comparison-table th,
.comparison-table td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--color-divider);
}

.comparison-table th {
  font-weight: 600;
  color: var(--color-text);
  background: var(--color-surface);
}

.comparison-table td {
  color: var(--color-text-muted);
}

.comparison-table .highlight-col {
  background: var(--color-primary-light);
  color: var(--color-text);
  font-weight: 500;
}

/* --- Misc Utilities --- */
.text-center { text-align: center; }
.text-primary { color: var(--color-primary); }
.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }