/**
 * Threads Sticker 官网组件与页面板块样式 (Components & Layout)
 * 包含导航、Hero 首屏、交互式模拟器、特性网格、常见问题手风琴与页脚
 */

/* ==========================================================================
   1. 顶部导航栏 (Navbar)
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 16px 0;
  background-color: rgba(255, 244, 221, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 2px solid transparent;
  transition: all 0.2s ease;
}

[data-theme="dark"] .site-header {
  background-color: rgba(24, 20, 16, 0.88);
}

.site-header.scrolled {
  border-bottom: var(--border-thick);
  box-shadow: 0 4px 0 var(--shadow-color);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  user-select: none;
}

.brand-logo-img {
  width: 36px;
  height: 36px;
  border-radius: 9px;
  border: 2px solid var(--ink-border);
  box-shadow: 2px 2px 0 var(--shadow-color);
  flex-shrink: 0;
}

.brand-title {
  font-size: 1.35rem;
  font-weight: 900;
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--ink-primary);
  white-space: nowrap;
}

.brand-title span.accent {
  color: var(--color-accent);
}

.header-pro-badge {
  flex-shrink: 0;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  gap: 20px;
  list-style: none;
  margin-right: 12px;
}

.nav-links a {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--ink-secondary);
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  transition: color 0.15s ease;
}

.nav-links a:hover {
  color: var(--ink-primary);
}

/* ==========================================================================
   2. 首屏展示区 (Hero Section)
   ========================================================================== */
.hero-section {
  padding: 56px 0 40px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 48px;
  align-items: center;
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.hero-title {
  font-size: clamp(2.2rem, 4.2vw, 3.4rem);
  line-height: 1.15;
  letter-spacing: -0.03em;
}

.hero-title .highlight {
  color: var(--color-accent);
  position: relative;
  display: inline-block;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--ink-secondary);
  max-width: 540px;
  line-height: 1.6;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  margin-top: 10px;
}

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ==========================================================================
   3. 语言切换器与全局 Toast 提示 (Language Switcher & Global Toast)
   ========================================================================== */
.lang-switcher-wrap {
  position: relative;
  display: inline-block;
}

.lang-menu {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  min-width: 130px;
  background-color: var(--surface-card);
  border: var(--border-thick);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  padding: 6px;
  list-style: none;
  z-index: 200;
  animation: fadeInPop 0.15s ease-out forwards;
}

.lang-menu.active {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.lang-option {
  width: 100%;
  text-align: left;
  padding: 8px 12px;
  background: none;
  border: none;
  border-radius: var(--radius-xs);
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--ink-primary);
  cursor: pointer;
  transition: background-color 0.12s ease;
}

.lang-option:hover {
  background-color: var(--color-sun);
}

/* 全局操作反馈 Toast (对齐 App GlobalToast) */
#web-global-toast {
  position: fixed;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%) translateY(30px) scale(0.9);
  background: var(--surface-card, #FFFDF7);
  color: var(--ink-primary, #26201A);
  border: var(--border-thick);
  box-shadow: var(--shadow-md);
  padding: 10px 22px;
  border-radius: var(--radius-pill);
  font-weight: 800;
  font-size: 0.92rem;
  display: flex;
  align-items: center;
  gap: 8px;
  z-index: 9999;
  opacity: 0;
  pointer-events: none;
  transition: all 0.25s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

#web-global-toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0) scale(1);
}

/* ==========================================================================
   4. 特性卡片网格 (Features Section)
   ========================================================================== */
.features-section {
  padding: 60px 0;
}

.section-head {
  text-align: center;
  margin-bottom: 42px;
}

.section-title {
  font-size: clamp(1.8rem, 3.2vw, 2.5rem);
  margin-bottom: 12px;
}

.section-desc {
  max-width: 580px;
  margin: 0 auto;
  font-size: 1.05rem;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.feature-card {
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  border-radius: var(--radius-lg);
  border: var(--border-thick);
  background-color: var(--surface-card);
  box-shadow: var(--shadow-md);
  position: relative;
}

.feature-icon-badge {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  border: var(--border-thick);
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 800;
}

.feature-text {
  font-size: 0.95rem;
  color: var(--ink-secondary);
  line-height: 1.55;
}

/* ==========================================================================
   5. 操作步骤指南 (How It Works)
   ========================================================================== */
.steps-section {
  padding: 50px 0 70px;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 36px;
}

.step-card {
  padding: 24px;
  border-radius: var(--radius-lg);
  border: var(--border-thick);
  background-color: var(--surface-card);
  box-shadow: var(--shadow-md);
  position: relative;
}

.step-number {
  position: absolute;
  top: -14px;
  left: 20px;
  padding: 2px 14px;
  border-radius: var(--radius-pill);
  border: var(--border-thick);
  font-weight: 900;
  font-size: 0.85rem;
  background-color: var(--color-sun);
  color: #26201A;
  box-shadow: 2px 2px 0 var(--shadow-color);
}

.step-card h3 {
  margin-top: 10px;
  font-size: 1.15rem;
  margin-bottom: 8px;
}

/* ==========================================================================
   6. 常见问题 (FAQ Section)
   ========================================================================== */
.faq-section {
  padding: 50px 0 70px;
}

.faq-list {
  max-width: 780px;
  margin: 32px auto 0;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  border: var(--border-thick);
  border-radius: var(--radius-md);
  background-color: var(--surface-card);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: all 0.2s ease;
}

.faq-question {
  width: 100%;
  padding: 18px 22px;
  text-align: left;
  background: none;
  border: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--ink-primary);
  cursor: pointer;
}

.faq-icon {
  font-size: 1.2rem;
  transition: transform 0.2s ease;
}

.faq-item.open .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.25s ease-out;
  padding: 0 22px;
}

.faq-item.open .faq-answer {
  padding-bottom: 18px;
}

.faq-answer p {
  color: var(--ink-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}