/* ==========================================================================
   COMPONENTS — Reusable UI Components
   Nav, buttons, cards, glyphs, notes, and name definitions.
   ========================================================================== */

/* ==========================================================================
   Navigation
   ========================================================================== */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-nav);
  background: rgba(14, 14, 17, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-line);
}

.nav__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  min-height: var(--nav-height);
  padding: var(--space-sm) var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Logo */
.nav__logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  z-index: calc(var(--z-nav) + 2);
}

.nav__logo svg {
  width: 40px;
  height: 40px;
  display: block;
  transition: filter 0.4s var(--ease-smooth);
}

.nav__logo:hover svg {
  filter: drop-shadow(0 0 8px rgba(123, 79, 224, 0.5));
}

.nav__logo-text {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--color-text);
  letter-spacing: -0.01em;
}

/* Desktop nav links */
.nav__links {
  display: flex;
  gap: var(--space-lg);
  align-items: center;
  font-size: 0.9rem;
  font-weight: 500;
}

.nav__link {
  text-decoration: none;
  color: var(--color-muted);
  transition: color var(--transition-base);
  position: relative;
}

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

.nav__link:focus-visible {
  outline: 2px solid var(--color-blue);
  outline-offset: 4px;
  border-radius: 4px;
}

/* Active nav link indicator */
.nav__link--active {
  color: var(--color-text);
}

/* Hamburger toggle */
.nav__toggle {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: calc(var(--z-nav) + 2);
  background: none;
  border: none;
  padding: 0;
}

.nav__toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  position: relative;
  transition: background var(--transition-base);
}

.nav__toggle-bar::before,
.nav__toggle-bar::after {
  content: "";
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  position: absolute;
  left: 0;
  transition: transform var(--transition-slow), top var(--transition-slow);
}

.nav__toggle-bar::before {
  top: -7px;
}

.nav__toggle-bar::after {
  top: 7px;
}

/* Hamburger open state */
.nav__toggle[aria-expanded="true"] .nav__toggle-bar {
  background: transparent;
}

.nav__toggle[aria-expanded="true"] .nav__toggle-bar::before {
  top: 0;
  transform: rotate(45deg);
}

.nav__toggle[aria-expanded="true"] .nav__toggle-bar::after {
  top: 0;
  transform: rotate(-45deg);
}

/* Mobile menu overlay */
.nav__mobile-overlay {
  display: none;
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
  display: inline-block;
  text-decoration: none;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.9rem;
  padding: 12px 26px;
  border-radius: var(--radius-md);
  transition: transform var(--transition-fast),
              box-shadow var(--transition-base),
              background var(--transition-base),
              opacity var(--transition-base);
  cursor: pointer;
  border: none;
  line-height: 1.4;
  text-align: center;
}

.btn:focus-visible {
  outline: 3px solid var(--color-blue);
  outline-offset: 2px;
}

/* Gradient button */
.btn--gradient {
  position: relative;
  overflow: hidden;
  background: var(--gradient-brand);
  color: var(--color-white);
  transition: transform 0.25s var(--ease-out-quart),
              box-shadow 0.3s var(--ease-out-quart);
}

.btn--gradient::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, rgba(255, 255, 255, 0.12) 0%, transparent 50%);
  opacity: 0;
  transition: opacity 0.3s var(--ease-out-quart);
}

.btn--gradient:hover {
  transform: translateY(-2px) scale(1.02);
  box-shadow: 0 12px 35px rgba(123, 79, 224, 0.45),
              0 4px 12px rgba(123, 79, 224, 0.2);
}

.btn--gradient:hover::before {
  opacity: 1;
}

.btn--gradient:active {
  transform: translateY(0) scale(0.98);
  transition-duration: 0.1s;
}

/* Ghost button */
.btn--ghost {
  background: transparent;
  color: var(--color-text);
  border: 1.5px solid var(--color-line-strong);
  transition: border-color 0.3s var(--ease-out-quart),
              color 0.3s var(--ease-out-quart),
              transform 0.25s var(--ease-out-quart),
              box-shadow 0.3s var(--ease-out-quart);
}

.btn--ghost:hover {
  border-color: var(--color-blue);
  color: var(--color-blue);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(63, 169, 232, 0.15);
}

.btn--ghost:active {
  transform: translateY(0) scale(0.98);
  transition-duration: 0.1s;
}

/* Dark button (used on gradient backgrounds) */
.btn--dark {
  background: var(--color-bg);
  color: var(--color-white);
}

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

/* Button loading state */
.btn--loading {
  pointer-events: none;
  opacity: 0.7;
  position: relative;
}

.btn--loading::after {
  content: "";
  width: 16px;
  height: 16px;
  border: 2px solid transparent;
  border-top-color: currentColor;
  border-radius: 50%;
  animation: btn-spin 0.6s linear infinite;
  display: inline-block;
  margin-left: 8px;
  vertical-align: middle;
}

@keyframes btn-spin {
  to { transform: rotate(360deg); }
}

/* ==========================================================================
   Cards
   ========================================================================== */

/* Belonging cards (thesis section) */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-xl);
  padding: 30px 26px;
  transition: transform 0.3s var(--ease-out-quart),
              border-color 0.3s var(--ease-out-quart),
              box-shadow 0.4s var(--ease-out-quart);
}

.card:hover {
  transform: translateY(-6px);
  border-color: rgba(123, 79, 224, 0.5);
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.35),
              0 0 30px rgba(123, 79, 224, 0.08);
}

.card:hover .glyph {
  transform: scale(1.12);
}

.card__title {
  font-size: 1.1rem;
  margin-bottom: 10px;
}

.card__text {
  font-size: 0.95rem;
  color: var(--color-muted);
}

/* ==========================================================================
   Glyph Icon Container
   ========================================================================== */

.glyph {
  width: 46px;
  height: 46px;
  border-radius: 13px;
  background: rgba(123, 79, 224, 0.14);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-md);
  flex-shrink: 0;
  transition: transform 0.3s var(--ease-out-quart);
}

.glyph--sm {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  margin-bottom: 16px;
}

.eco:hover .glyph--sm {
  transform: scale(1.15);
}

/* ==========================================================================
   Info Note Banner
   ========================================================================== */

.info-note {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  background: rgba(63, 169, 232, 0.07);
  border: 1px solid rgba(63, 169, 232, 0.25);
  border-radius: var(--radius-lg);
  padding: var(--space-md) 22px;
  max-width: 720px;
  font-size: 0.95rem;
  color: var(--color-muted);
}

.info-note b,
.info-note strong {
  color: var(--color-text);
}

.info-note svg {
  flex-shrink: 0;
  margin-top: 2px;
}

/* ==========================================================================
   Name Definition Box
   ========================================================================== */

.name-def {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  margin-top: var(--space-xs);
  background: var(--color-surface);
  border: 1px solid var(--color-line-strong);
  border-radius: var(--radius-lg);
  padding: 16px 22px;
}

.name-def svg {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
}

.name-def__text {
  font-size: 0.95rem;
  color: var(--color-muted);
}

.name-def__text b {
  color: var(--color-text);
  font-family: var(--font-heading);
}

/* ==========================================================================
   Back-to-Top Button
   ========================================================================== */

.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  z-index: var(--z-overlay);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-brand);
  color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  border: none;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: opacity var(--transition-slow),
              visibility var(--transition-slow),
              transform 0.3s var(--ease-elastic),
              box-shadow 0.3s var(--ease-out-quart);
}

.back-to-top--visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-3px) scale(1.08);
  box-shadow: 0 12px 30px rgba(123, 79, 224, 0.5);
}

.back-to-top:hover svg {
  animation: arrow-bounce 0.6s var(--ease-elastic);
}

@keyframes arrow-bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-3px); }
}

.back-to-top:focus-visible {
  outline: 3px solid var(--color-blue);
  outline-offset: 2px;
}

.back-to-top svg {
  width: 20px;
  height: 20px;
}