/* ============================================
   Header — Thest.io
   ============================================ */

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-height);
  border-bottom: 1px solid var(--color-border-soft);
  transition:
    background-color var(--transition-base),
    border-color var(--transition-base),
    box-shadow var(--transition-base);
}

.header--transparent {
  background: linear-gradient(180deg, rgba(250, 247, 244, 0.85) 0%, rgba(250, 247, 244, 0) 100%);
}

.header--solid {
  background: rgba(250, 247, 244, 0.96);
  border-color: var(--color-border);
}

.header--scrolled,
.header--solid.header--scrolled {
  background: rgba(250, 247, 244, 0.96);
  border-color: var(--color-border);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 1px 3px rgba(28, 25, 23, 0.04);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container-wide);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  z-index: 1001;
}

.logo__svg {
  height: 28px;
  width: auto;
}

/* Default state */
.logo__node-primary {
  fill: var(--color-primary);
  transition: fill var(--transition-base);
}

.logo__conn {
  stroke: rgba(28, 25, 23, 0.25);
  transition: stroke var(--transition-base);
}

.logo__node-accent,
.logo__dot {
  fill: var(--color-accent);
}

.logo__text-main {
  fill: var(--color-primary);
  transition: fill var(--transition-base);
}

.logo__text-accent {
  fill: var(--color-accent);
}

/* Scrolled state */
.header--scrolled .logo__node-primary {
  fill: var(--color-primary);
}

.header--scrolled .logo__conn {
  stroke: rgba(28, 25, 23, 0.3);
}

.header--scrolled .logo__text-main {
  fill: var(--color-primary);
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav__link {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  position: relative;
  transition: color var(--transition-fast);
}

.nav__link::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -0.4rem;
  width: 0;
  height: 2px;
  border-radius: 2px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

.nav__link:hover::after,
.nav__link--active::after {
  width: 100%;
}

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

.header--scrolled .nav__link {
  color: var(--color-text-secondary);
}

.header--scrolled .nav__link:hover,
.header--scrolled .nav__link--active {
  color: var(--color-text);
}

.nav__cta {
  flex-shrink: 0;
}

.nav__cta .btn {
  border-radius: var(--radius-sm);
  padding: 0.55rem 1rem;
}

/* Mobile hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 28px;
  height: 28px;
  z-index: 1001;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0;
}

.hamburger__line {
  width: 100%;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all var(--transition-base);
}

.header--scrolled .hamburger__line {
  background: var(--color-text);
}

.hamburger[aria-expanded='true'] .hamburger__line:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.hamburger[aria-expanded='true'] .hamburger__line:nth-child(2) {
  opacity: 0;
}

.hamburger[aria-expanded='true'] .hamburger__line:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile */
@media (max-width: 1024px) {
  .hamburger {
    display: flex;
  }

  .nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 100%;
    max-width: 380px;
    height: 100vh;
    background: var(--color-white);
    border-left: 1px solid var(--color-border);
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    padding: var(--space-3xl);
    gap: var(--space-xl);
    transition: right var(--transition-emphasized);
    box-shadow: var(--shadow-xl);
  }

  .nav--open {
    right: 0;
  }

  .nav__list {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-lg);
  }

  .nav__link {
    font-size: clamp(1.15rem, 4vw, 1.35rem);
    color: var(--color-text-secondary);
  }

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

  .nav__cta {
    width: 100%;
  }

  .nav__cta .btn {
    width: 100%;
  }

  .nav-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(2px);
    z-index: 999;
  }

  .nav-overlay--visible {
    display: block;
  }
}

@media (max-width: 480px) {
  .header__inner {
    padding: 0 var(--space-md);
  }

  .logo__svg {
    height: 24px;
  }
}