/* ===========================
   SCROLL PROGRESS BAR
   =========================== */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 0%;
  background: var(--gradient-cosmic);
  z-index: 10001;
  pointer-events: none;
}

/* ===========================
   BUTTONS
   =========================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-cn);
  font-size: var(--text-sm);
  font-weight: 500;
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius-full);
  transition:
    background var(--dur-fast) ease,
    color var(--dur-fast) ease,
    transform var(--dur-fast) ease,
    box-shadow var(--dur-fast) ease;
  cursor: pointer;
  position: relative;
  white-space: nowrap;
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0, 113, 227, 0.25);
  color: #fff;
}

.btn-ghost {
  color: var(--color-accent);
  border: none;
  background: transparent;
}

.btn-ghost:hover {
  background: var(--color-accent-light);
  color: var(--color-accent-hover);
}

.btn-lg {
  padding: 0.85rem 2rem;
  font-size: var(--text-base);
}

.btn-sm {
  padding: 0.4rem 1.1rem;
  font-size: var(--text-xs);
  font-weight: 600;
}

/* ===========================
   NAVIGATION
   =========================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--nav-h);
  z-index: 1000;
  padding: 0 var(--space-8);
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background var(--dur-base) ease, border-color var(--dur-base) ease, backdrop-filter var(--dur-base) ease;
}

/* 沉浸模式（hero区）：文字全白 */
.navbar:not(.scrolled) .nav-links a {
  color: rgba(255, 255, 255, 0.7);
}

.navbar:not(.scrolled) .nav-links a:hover,
.navbar:not(.scrolled) .nav-links a.active {
  color: #fff;
}

.navbar:not(.scrolled) .nav-links a::after {
  background: #fff;
}

.navbar:not(.scrolled) .lang-switch {
  color: rgba(255, 255, 255, 0.6);
}

.navbar:not(.scrolled) .lang-switch:hover {
  color: #fff;
}

.navbar:not(.scrolled) .btn-primary {
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.25);
  backdrop-filter: blur(8px);
}

.navbar:not(.scrolled) .btn-primary:hover {
  background: rgba(255, 255, 255, 0.25);
}

.navbar:not(.scrolled) .hamburger span {
  background: #fff;
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom-color: var(--color-border);
}

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

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
  min-width: 80px;
}

.nav-logo:hover {
  color: var(--color-text);
}

/* nav-logo-text 已移除 */

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-10);
}

.nav-links a {
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--color-text-secondary);
  transition: color var(--dur-fast) ease;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1.5px;
  background: var(--color-text);
  border-radius: 1px;
  transition: width var(--dur-base) var(--ease-out);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-text);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

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

/* Language Dropdown */
.lang-dropdown {
  position: relative;
}

.lang-switch {
  display: flex;
  align-items: center;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 4px 0;
  transition: color var(--dur-fast) ease;
  white-space: nowrap;
}

.lang-switch:hover {
  color: var(--color-accent);
}

.lang-globe {
  opacity: 0.5;
  transition: opacity var(--dur-fast) ease;
}

.lang-switch:hover .lang-globe {
  opacity: 0.85;
}

.lang-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 24px rgba(0,0,0,0.1);
  padding: 4px;
  min-width: 120px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s;
  z-index: 1000;
}

.lang-dropdown:hover .lang-menu,
.lang-menu.is-open {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.lang-option {
  display: block;
  width: 100%;
  padding: 8px 12px;
  border: none;
  background: none;
  font-family: var(--font-body);
  font-size: 13px;
  color: var(--color-text-secondary);
  cursor: pointer;
  border-radius: calc(var(--radius-lg) - 4px);
  text-align: left;
  transition: background 0.15s ease, color 0.15s ease;
}

.lang-option:hover {
  background: var(--color-bg-alt);
  color: var(--color-text);
}

.lang-option.is-active {
  color: var(--color-accent);
  font-weight: 600;
}

/* === Hamburger (2-line) === */
.hamburger {
  display: none;
  width: 20px;
  height: 14px;
  position: relative;
  z-index: 1001;
}

.hamburger span {
  position: absolute;
  left: 0;
  width: 100%;
  height: 1.5px;
  background: var(--color-text);
  border-radius: 1px;
  transition: all var(--dur-base) var(--ease-out);
}

.hamburger span:first-child { top: 0; }
.hamburger span:last-child { bottom: 0; }

.hamburger.active span:first-child {
  top: 50%;
  transform: translateY(-50%) rotate(45deg);
}

.hamburger.active span:last-child {
  bottom: 50%;
  transform: translateY(50%) rotate(-45deg);
}

/* === Mobile Menu === */
.mobile-menu {
  position: fixed;
  inset: 0;
  background: rgba(255, 255, 255, 0.97);
  backdrop-filter: blur(24px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-10);
  z-index: 999;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--dur-base) ease;
}

.mobile-menu.active {
  opacity: 1;
  pointer-events: all;
}

.mobile-menu a {
  font-size: var(--text-2xl);
  font-weight: 600;
  color: var(--color-text);
}

.mobile-menu a:hover {
  color: var(--color-accent);
}

/* ===========================
   BROWSER MOCKUP
   =========================== */
/* Browser mockup styles removed — replaced by platform-item cards */