/* ==========================================================================
   Components — Navigation, Footer, Buttons, Cards, Section Headers, Grids
   ========================================================================== */

/* --------------------------------------------------------------------------
   Site Navigation
   -------------------------------------------------------------------------- */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 60px;
  z-index: 1000;
  background: transparent;
  transition: background var(--duration-normal) var(--ease-out),
              box-shadow var(--duration-normal) var(--ease-out);
}

.site-nav--scrolled {
  background: rgba(250, 250, 250, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 1px 0 var(--color-border);
}

.site-nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-3);
}

.site-nav__logo {
  font-size: 18px;
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.site-nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.site-nav__link {
  font-size: 14px;
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-sub);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-out);
}

.site-nav__link:hover {
  color: var(--color-text);
}

/* App page navigation — back link + app name */
.site-nav__back {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-sub);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-out);
}

.site-nav__back::before {
  content: '\2190'; /* ← arrow */
  font-size: 16px;
}

.site-nav__back:hover {
  color: var(--color-text);
}

.site-nav__app-name {
  font-size: 14px;
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
}

/* --------------------------------------------------------------------------
   Site Footer
   -------------------------------------------------------------------------- */
.site-footer {
  padding: var(--space-6) 0;
  border-top: 1px solid var(--color-border);
  text-align: center;
  font-size: 14px;
  color: var(--color-text-muted);
}

.site-footer__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-3);
}

.site-footer__link {
  color: var(--color-text-sub);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-out);
}

.site-footer__link:hover {
  color: var(--color-text);
}

/* --------------------------------------------------------------------------
   Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  font-size: 15px;
  font-weight: var(--font-weight-semibold);
  line-height: 1;
  border: none;
  border-radius: 8px;
  text-decoration: none;
  cursor: pointer;
  transition: background var(--duration-fast) var(--ease-out),
              color var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out),
              transform var(--duration-fast) var(--ease-out);
}

.btn:active {
  transform: scale(0.98);
}

/* Primary — dark fill */
.btn--primary {
  background: var(--color-text);
  color: #FFFFFF;
}

.btn--primary:hover {
  background: #2C2C2E;
}

/* Secondary — outlined */
.btn--secondary {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text);
}

.btn--secondary:hover {
  background: var(--color-surface);
}

/* Large variant */
.btn--large {
  padding: 18px 40px;
  font-size: 17px;
  border-radius: 10px;
}

/* Accent — uses app accent color */
.btn--accent {
  background: var(--color-app-accent);
  color: #FFFFFF;
}

.btn--accent:hover {
  opacity: 0.9;
}

/* --------------------------------------------------------------------------
   Feature Card
   -------------------------------------------------------------------------- */
.feature-card {
  background: #FFFFFF;
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: var(--space-4);
  transition: transform var(--duration-normal) var(--ease-out),
              box-shadow var(--duration-normal) var(--ease-out);
}

.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
}

.feature-card__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-surface);
  margin-bottom: var(--space-2);
  font-size: 20px;
}

.feature-card__title {
  font-size: 18px;
  font-weight: var(--font-weight-semibold);
  line-height: 1.3;
  margin-bottom: var(--space-1);
  letter-spacing: -0.01em;
}

.feature-card__desc {
  font-size: 15px;
  color: var(--color-text-sub);
  line-height: 1.55;
}

/* --------------------------------------------------------------------------
   Section Header
   -------------------------------------------------------------------------- */
.section-header {
  margin-bottom: var(--space-8);
}

.section-header__label {
  display: inline-block;
  font-size: var(--font-size-label);
  font-weight: var(--font-weight-semibold);
  letter-spacing: var(--letter-spacing-label);
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}

.section-header__title {
  font-size: clamp(32px, 4vw, 56px);
  font-weight: var(--font-weight-black);
  line-height: var(--line-height-heading);
  letter-spacing: var(--letter-spacing-hero);
}

.section-header__desc {
  font-size: var(--font-size-body);
  color: var(--color-text-sub);
  margin-top: var(--space-2);
  max-width: var(--max-width-narrow);
}

/* --------------------------------------------------------------------------
   Feature Grid
   -------------------------------------------------------------------------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-3);
}