/**
 * Guanyiai Design System - Footer
 * Footer layout, sitemap columns, responsive
 * Version: 1.0
 * Date: 2026-05-30
 */

/* ============================================
   FOOTER LAYOUT
   ============================================ */

.footer {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border-subtle);
  margin-top: var(--section-gap);
  position: relative;
}

.footer__inner {
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: var(--footer-padding);
}

@media (min-width: 768px) {
  .footer__inner {
    padding: var(--footer-padding-lg);
  }
}

/* ============================================
   FOOTER: TOP SECTION (Sitemap Columns)
   ============================================ */

.footer__top {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--footer-gap);
  padding-bottom: var(--space-10);
  border-bottom: 1px solid var(--color-border);
}

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

@media (min-width: 768px) {
  .footer__top {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (min-width: 1024px) {
  .footer__top {
    grid-template-columns: 2fr repeat(3, 1fr);
  }
}

/* ============================================
   FOOTER: BRAND COLUMN
   ============================================ */

.footer__brand {
  max-width: 320px;
}

.footer__brand-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  margin-bottom: var(--space-4);
}

.footer__brand-logo-icon {
  font-size: var(--text-2xl);
}

.footer__brand-logo-text {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  letter-spacing: var(--tracking-wider);
}

.footer__brand-desc {
  font-size: var(--text-body-sm);
  color: var(--color-text-tertiary);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-5);
}

/* Social Links */
.footer__social {
  display: flex;
  gap: var(--space-3);
}

.footer__social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  background: var(--color-bg-tertiary);
  color: var(--color-text-tertiary);
  text-decoration: none;
  transition: background-color var(--duration-fast) var(--ease-default),
              color var(--duration-fast) var(--ease-default),
              transform var(--duration-fast) var(--ease-default);
}

.footer__social-link:hover {
  background: var(--color-primary-100);
  color: var(--color-primary-600);
  transform: translateY(-2px);
}

.footer__social-link svg,
.footer__social-link img {
  width: 18px;
  height: 18px;
}

/* ============================================
   FOOTER: SITEMAP COLUMNS
   ============================================ */

.footer__column-title {
  font-family: var(--font-sans);
  font-size: var(--text-body-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
  letter-spacing: var(--tracking-wide);
}

.footer__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2-5);
}

.footer__link {
  font-size: var(--text-body-sm);
  color: var(--color-text-tertiary);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-default),
              padding-left var(--duration-fast) var(--ease-default);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.footer__link:hover {
  color: var(--color-text-link);
  padding-left: var(--space-1);
}

.footer__link-icon {
  width: 16px;
  height: 16px;
  font-size: var(--text-sm);
  opacity: 0.6;
  transition: opacity var(--duration-fast) var(--ease-default);
}

.footer__link:hover .footer__link-icon {
  opacity: 1;
}

/* Link with external indicator */
.footer__link--external::after {
  content: '';
  width: 12px;
  height: 12px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2378716c' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-size: contain;
  flex-shrink: 0;
}

/* ============================================
   FOOTER: BOTTOM SECTION
   ============================================ */

.footer__bottom {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  padding-top: var(--space-8);
}

@media (min-width: 768px) {
  .footer__bottom {
    flex-direction: row;
    justify-content: space-between;
  }
}

/* Copyright */
.footer__copyright {
  font-size: var(--text-sm);
  color: var(--color-text-tertiary);
  text-align: center;
}

@media (min-width: 768px) {
  .footer__copyright {
    text-align: left;
  }
}

.footer__copyright-link {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-default);
}

.footer__copyright-link:hover {
  color: var(--color-text-link);
}

/* Legal Links */
.footer__legal {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  flex-wrap: wrap;
  justify-content: center;
}

.footer__legal-link {
  font-size: var(--text-xs);
  color: var(--color-text-tertiary);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-default);
  white-space: nowrap;
}

.footer__legal-link:hover {
  color: var(--color-text-link);
}

.footer__legal-divider {
  width: 1px;
  height: 12px;
  background: var(--color-border);
}

/* ============================================
   FOOTER: BACK TO TOP
   ============================================ */

.footer__back-to-top {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-tertiary);
  text-decoration: none;
  box-shadow: var(--shadow-sm);
  transition: background-color var(--duration-fast) var(--ease-default),
              color var(--duration-fast) var(--ease-default),
              box-shadow var(--duration-fast) var(--ease-default),
              transform var(--duration-fast) var(--ease-default);
}

.footer__back-to-top:hover {
  background: var(--color-primary-50);
  color: var(--color-primary-600);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.footer__back-to-top svg {
  width: 18px;
  height: 18px;
}

/* ============================================
   FOOTER: NEWSLETTER (Optional)
   ============================================ */

.footer__newsletter {
  margin-top: var(--space-6);
  padding: var(--space-6);
  background: var(--color-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-xl);
}

.footer__newsletter-title {
  font-family: var(--font-serif);
  font-size: var(--text-body-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.footer__newsletter-desc {
  font-size: var(--text-body-sm);
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-4);
}

.footer__newsletter-form {
  display: flex;
  gap: var(--space-3);
  max-width: 400px;
}

.footer__newsletter-input {
  flex: 1;
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-sans);
  font-size: var(--text-body-sm);
  color: var(--color-text-primary);
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-button);
  transition: border-color var(--duration-fast) var(--ease-default),
              box-shadow var(--duration-fast) var(--ease-default);
  outline: none;
}

.footer__newsletter-input:focus {
  border-color: var(--color-primary-400);
  box-shadow: 0 0 0 3px var(--color-primary-100);
  background: var(--color-surface);
}

.footer__newsletter-input::placeholder {
  color: var(--color-text-muted);
}

.footer__newsletter-btn {
  padding: var(--space-3) var(--space-5);
  font-family: var(--font-sans);
  font-size: var(--text-body-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-inverse);
  background: var(--color-primary-600);
  border: none;
  border-radius: var(--radius-button);
  cursor: pointer;
  transition: background-color var(--duration-fast) var(--ease-default),
              box-shadow var(--duration-fast) var(--ease-default);
  white-space: nowrap;
}

.footer__newsletter-btn:hover {
  background: var(--color-primary-700);
  box-shadow: var(--shadow-primary-md);
}

/* ============================================
   FOOTER: COMPACT / SIMPLE VARIANT
   ============================================ */

.footer--simple {
  text-align: center;
}

.footer--simple .footer__inner {
  padding: var(--space-8) var(--page-padding);
}

.footer--simple .footer__bottom {
  flex-direction: column;
}

.footer--simple .footer__copyright {
  text-align: center;
}

/* Simple footer: horizontal link list */
.footer--simple .footer__links {
  flex-direction: row;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-4);
}

/* ============================================
   FOOTER: RESPONSIVE ADJUSTMENTS
   ============================================ */

@media (max-width: 640px) {
  .footer__inner {
    padding: var(--space-8) var(--page-padding);
  }

  .footer__brand {
    max-width: 100%;
    text-align: center;
  }

  .footer__brand-logo {
    justify-content: center;
  }

  .footer__social {
    justify-content: center;
  }

  .footer__column-title {
    text-align: center;
  }

  .footer__links {
    align-items: center;
  }

  .footer__newsletter-form {
    flex-direction: column;
    max-width: 100%;
  }

  .footer__newsletter-btn {
    width: 100%;
  }

  .footer__legal {
    justify-content: center;
    gap: var(--space-3);
  }

  .footer__legal-divider {
    display: none;
  }
}

@media (min-width: 640px) and (max-width: 767px) {
  .footer__brand {
    grid-column: 1 / -1;
    max-width: 100%;
    text-align: center;
  }

  .footer__brand-logo {
    justify-content: center;
  }

  .footer__social {
    justify-content: center;
  }
}

/* ============================================
   FOOTER: DARK MODE ADJUSTMENTS
   ============================================ */

[data-theme="dark"] .footer {
  background: var(--color-bg-tertiary);
}

[data-theme="dark"] .footer__newsletter {
  background: var(--color-bg-secondary);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .footer {
    background: var(--color-bg-tertiary);
  }

  :root:not([data-theme="light"]) .footer__newsletter {
    background: var(--color-bg-secondary);
  }
}