/* ===== HEADER ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-height);
  background: rgba(252, 252, 251, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-base), box-shadow var(--transition-base);
}

.header--scrolled {
  border-bottom-color: var(--paper-border);
  box-shadow: 0 1px 8px rgba(0,0,0,0.04);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.header__logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

.header__logo img {
  height: 36px;
  width: auto;
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav__link {
  font-size: var(--fs-small);
  font-weight: 500;
  color: var(--ink-light);
  transition: color var(--transition-fast);
  position: relative;
}

.nav__link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1.5px;
  background: var(--primary);
  transition: width var(--transition-base);
  border-radius: 1px;
}

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

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

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 4px;
  width: 32px;
}

.menu-toggle__line {
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.menu-toggle--active .menu-toggle__line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle--active .menu-toggle__line:nth-child(2) {
  opacity: 0;
}

.menu-toggle--active .menu-toggle__line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile Nav */
.mobile-nav {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--paper-light);
  z-index: 999;
  padding: 2rem;
  flex-direction: column;
  gap: 1rem;
  opacity: 0;
  transform: translateY(-10px);
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.mobile-nav--open {
  display: flex;
  opacity: 1;
  transform: translateY(0);
}

.mobile-nav__link {
  font-size: 1.2rem;
  font-weight: 500;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--paper-border);
  color: var(--ink);
}

/* ===== BUTTONS — sketchy/paper style ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  border-radius: 8px;
  font-size: var(--fs-small);
  font-weight: 600;
  transition: all var(--transition-base);
  white-space: nowrap;
  position: relative;
}

.btn--primary {
  background: var(--primary);
  color: var(--paper-light);
  border: 1.5px solid var(--primary);
}

.btn--primary:hover {
  background: var(--primary-dark);
  border-color: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: 0 3px 16px rgba(0, 54, 255, 0.25);
}

.btn--outline {
  border: 1.5px solid var(--paper-border);
  color: var(--ink);
  background: var(--paper-light);
}

.btn--outline:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--paper-light);
}

.btn--ghost {
  color: var(--ink);
  font-weight: 600;
}

.btn--ghost:hover {
  opacity: 0.7;
}

.btn--ghost .btn__arrow {
  transition: transform var(--transition-fast);
}

.btn--ghost:hover .btn__arrow {
  transform: translateX(3px);
}

.btn__arrow {
  display: inline-block;
  transition: transform var(--transition-fast);
}

.btn--lg {
  padding: 1rem 2.25rem;
  font-size: 1rem;
}

.btn--dark {
  background: var(--ink);
  color: var(--paper-light);
  border: 1.5px solid var(--ink);
}

.btn--dark:hover {
  background: #3a3a3a;
  transform: translateY(-1px);
}

.btn--white {
  background: var(--paper-light);
  color: var(--ink);
  border: 1.5px solid var(--paper-border);
}

.btn--white:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-1px);
}

/* ===== CARDS — paper style ===== */
.card {
  background: var(--paper-light);
  border: 1.5px solid var(--paper-border);
  border-radius: var(--radius-md);
  padding: 2rem;
  transition: all var(--transition-base);
  position: relative;
}

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

.card__illustration {
  width: 100%;
  height: 140px;
  margin-bottom: var(--gap-md);
  display: flex;
  align-items: center;
  justify-content: center;
}

.card__title {
  font-size: var(--fs-h3);
  margin-bottom: 0.75rem;
}

.card__desc {
  font-size: var(--fs-small);
  margin-bottom: var(--gap-md);
}

.card__link {
  font-size: var(--fs-small);
  font-weight: 600;
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  transition: gap var(--transition-fast);
}

.card__link:hover {
  gap: 0.6rem;
}

/* ===== PROJECT CARD ===== */
.project-card {
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--paper-light);
  border: 1.5px solid var(--paper-border);
  transition: all var(--transition-base);
}

.project-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
}

.project-card__preview {
  aspect-ratio: 16/10;
  overflow: hidden;
  position: relative;
  background: var(--paper-mid);
}

.project-card__body {
  padding: 1.5rem;
}

.project-card__title {
  font-size: var(--fs-h3);
  margin-bottom: 0.5rem;
}

.project-card__desc {
  font-size: var(--fs-small);
  margin-bottom: 1rem;
}

.project-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tag {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  font-size: var(--fs-caption);
  font-weight: 500;
  background: var(--paper-mid);
  border: 1px solid var(--paper-border);
  border-radius: var(--radius-full);
  color: var(--ink-light);
}

/* ===== METRICS ===== */
.metrics {
  display: flex;
  justify-content: center;
  gap: clamp(2rem, 5vw, 5rem);
  flex-wrap: wrap;
}

.metric {
  text-align: center;
}

.metric__value {
  font-size: clamp(2rem, 3.5vw, 3.2rem);
  font-weight: 700;
  color: var(--ink);
  line-height: 1;
  margin-bottom: 0.5rem;
}

.metric__label {
  font-size: var(--fs-small);
  color: var(--ink-faint);
}

/* ===== CTA SECTION ===== */
.cta {
  text-align: center;
  padding: clamp(3rem, 6vw, 5rem);
  background: var(--paper-mid);
  border-radius: var(--radius-lg);
  border: 1.5px solid var(--paper-border);
}

.cta__title {
  color: var(--ink);
  margin-bottom: var(--gap-md);
}

.cta__desc {
  color: var(--ink-light);
  max-width: 480px;
  margin: 0 auto var(--gap-lg);
}

/* ===== FOOTER ===== */
.footer {
  background: var(--paper-mid);
  color: var(--ink-light);
  padding: clamp(3rem, 5vw, 4rem) 0 2rem;
  border-top: 1.5px solid var(--paper-border);
}

.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: var(--gap-lg);
  margin-bottom: var(--gap-lg);
}

.footer__brand p {
  margin-top: 1rem;
  font-size: var(--fs-small);
  color: var(--ink-faint);
  max-width: 280px;
}

.footer__brand img {
  height: 32px;
  width: auto;
}

.footer__heading {
  font-size: var(--fs-small);
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer__link {
  font-size: var(--fs-small);
  color: var(--ink-faint);
  transition: color var(--transition-fast);
}

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

.footer__bottom {
  border-top: 1px solid var(--paper-border);
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--fs-caption);
  color: var(--ink-faint);
}

.footer__requisites {
  font-size: var(--fs-caption);
  color: var(--ink-faint);
  line-height: 1.8;
}

/* ===== FORM — paper style ===== */
.form__group {
  margin-bottom: var(--gap-md);
}

.form__label {
  display: block;
  font-size: var(--fs-small);
  font-weight: 500;
  margin-bottom: 0.5rem;
  color: var(--ink);
}

.form__input,
.form__textarea {
  width: 100%;
  padding: 0.875rem 1rem;
  border: 1.5px solid var(--paper-border);
  border-radius: var(--radius-sm);
  font-size: var(--fs-body);
  color: var(--ink);
  background: var(--paper-light);
  transition: border-color var(--transition-fast);
}

.form__input:focus,
.form__textarea:focus {
  outline: none;
  border-color: var(--ink);
}

.form__textarea {
  resize: vertical;
  min-height: 140px;
}

.form__input::placeholder,
.form__textarea::placeholder {
  color: var(--ink-faint);
}

/* ===== BREADCRUMB ===== */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: var(--fs-small);
  color: var(--ink-faint);
  margin-bottom: var(--gap-lg);
  padding-top: calc(var(--header-height) + 2rem);
}

.breadcrumb a {
  color: var(--ink-faint);
  transition: color var(--transition-fast);
}

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

.breadcrumb__separator {
  color: var(--paper-border);
}

.breadcrumb__current {
  color: var(--ink);
  font-weight: 500;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .menu-toggle {
    display: flex;
  }

  .nav {
    display: none;
  }

  .header__cta {
    display: none;
  }

  .footer__grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .footer__bottom {
    flex-direction: column;
    gap: 0.5rem;
    text-align: center;
  }

  .metrics {
    gap: 2rem;
  }

  .metric {
    flex: 0 0 auto;
    min-width: 120px;
  }
}