/* ===== 主题变量 ===== */
:root {
  --blue: #0B57D0;
  --blue-light: #D3E3FD;
  --blue-soft: #EDF3FE;
  --blue-dark: #0842A0;
  --surface: #F8F9FF;
  --surface-card: #FFFFFF;
  --surface-elevated: #FFFFFF;
  --text: #1A1C1E;
  --text-sub: #5E6470;
  --text-muted: #9AA0A6;
  --outline: #E2E7F0;
  --overlay: rgba(0, 0, 0, 0.4);
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.04), 0 8px 32px rgba(11, 87, 208, 0.06);
  --shadow-elevated: 0 12px 40px rgba(11, 87, 208, 0.18), 0 4px 12px rgba(0, 0, 0, 0.04);
  --transition-theme: background-color 0.4s cubic-bezier(0.4, 0, 0.2, 1),
                     color 0.4s cubic-bezier(0.4, 0, 0.2, 1),
                     border-color 0.4s cubic-bezier(0.4, 0, 0.2, 1),
                     box-shadow 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --blue: #A8C7FA;
  --blue-light: #004A77;
  --blue-soft: #1A2C42;
  --blue-dark: #D3E3FD;
  --surface: #111318;
  --surface-card: #1E1F24;
  --surface-elevated: #2A2B31;
  --text: #E3E2E6;
  --text-sub: #C4C6CF;
  --text-muted: #8E9099;
  --outline: #3A3C44;
  --overlay: rgba(0, 0, 0, 0.7);
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.2), 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-elevated: 0 12px 40px rgba(0, 0, 0, 0.4), 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* ===== 基础重置 ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

*:focus,
*:focus-visible,
*:active {
  outline: none !important;
  -webkit-tap-highlight-color: transparent !important;
}

button:focus,
a:focus,
input:focus,
button:focus-visible,
a:focus-visible {
  outline: none !important;
  box-shadow: none !important;
  -webkit-tap-highlight-color: transparent !important;
}

button::-moz-focus-inner,
a::-moz-focus-inner {
  border: 0;
  outline: none;
}

html {
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  background: var(--surface);
  font-family: 'Roboto', system-ui, sans-serif;
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  transition: var(--transition-theme);
}

/* ===== 主题切换动画 ===== */
.theme-ripple {
  position: fixed;
  border-radius: 50%;
  background: var(--surface);
  pointer-events: none;
  z-index: 9999;
  transform: scale(0);
  opacity: 0.85;
}

.theme-ripple.expanding {
  animation: rippleExpand 0.75s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes rippleExpand {
  0% { transform: scale(0); opacity: 0.85; }
  100% { transform: scale(1); opacity: 0; }
}

/* ===== 顶部导航 ===== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--surface) 85%, transparent);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--outline);
  transition: var(--transition-theme);
}

.navbar-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
}

.brand-icon {
  width: 36px;
  height: 36px;
  background: var(--blue);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  transition: var(--transition-theme);
}

.brand-icon img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.brand-name {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -0.2px;
}

.brand-name span {
  color: var(--blue);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-sub);
  text-decoration: none;
  padding: 8px 16px;
  border-radius: 100px;
  transition: background 0.2s, color 0.2s;
}

.nav-links a:hover {
  background: var(--blue-soft);
  color: var(--blue);
}

.nav-links a.active {
  color: var(--blue);
  background: var(--blue-soft);
}

.nav-cta {
  font-size: 0.875rem;
  font-weight: 500;
  color: #fff !important;
  background: var(--blue);
  padding: 9px 20px !important;
  border-radius: 100px !important;
  transition: background 0.2s, transform 0.15s !important;
}

[data-theme="dark"] .nav-cta {
  color: #111318 !important;
}

.nav-cta:hover {
  background: var(--blue-dark) !important;
  transform: translateY(-1px);
}

.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-sub);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, color 0.2s;
  margin-left: 6px;
}

.theme-toggle:hover {
  background: var(--blue-soft);
  color: var(--blue);
}

.theme-toggle .material-symbols-outlined {
  font-size: 22px;
  font-variation-settings: 'FILL' 1;
  transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.theme-toggle.rotating .material-symbols-outlined {
  transform: rotate(360deg);
}

/* ===== Hero 区域 ===== */
.hero {
  max-width: 1100px;
  margin: 0 auto;
  padding: 72px 24px 56px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
}

.hero-content {
  animation: fadeUp 0.6s ease both;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--blue);
  background: var(--blue-soft);
  padding: 6px 14px;
  border-radius: 100px;
  margin-bottom: 24px;
  letter-spacing: 0.2px;
  transition: var(--transition-theme);
}

.hero-badge .material-symbols-outlined {
  font-size: 15px;
  font-variation-settings: 'FILL' 1;
}

.hero-title {
  font-size: 3.4rem;
  font-weight: 700;
  letter-spacing: -1.5px;
  line-height: 1.1;
  color: var(--text);
  margin-bottom: 14px;
}

.hero-title .accent {
  color: var(--blue);
  transition: var(--transition-theme);
}

.hero-tagline {
  font-size: 1.15rem;
  font-weight: 400;
  color: var(--text-sub);
  line-height: 1.65;
  margin-bottom: 36px;
  max-width: 440px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 16px 32px;
  background: var(--blue);
  color: #fff;
  border: none;
  border-radius: 100px;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.2px;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s, box-shadow 0.25s;
  box-shadow: 0 2px 12px rgba(11, 87, 208, 0.28);
}

[data-theme="dark"] .btn-primary {
  color: #111318;
  box-shadow: 0 2px 12px rgba(168, 199, 250, 0.2);
}

.btn-primary .material-symbols-outlined {
  font-size: 22px;
  font-variation-settings: 'FILL' 1;
}

.btn-primary:hover {
  background: var(--blue-dark);
  box-shadow: 0 6px 20px rgba(11, 87, 208, 0.38);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0) scale(0.98);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 16px 28px;
  background: transparent;
  color: var(--blue);
  border: 1.5px solid var(--outline);
  border-radius: 100px;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, transform 0.15s;
}

.btn-secondary:hover {
  background: var(--blue-soft);
  border-color: var(--blue-light);
  transform: translateY(-1px);
}

.btn-secondary .material-symbols-outlined {
  font-size: 20px;
}

.hero-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-top: 32px;
  font-size: 0.82rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}

.hero-meta span {
  display: flex;
  align-items: center;
  gap: 5px;
}

.hero-meta .material-symbols-outlined {
  font-size: 16px;
  color: var(--blue);
  font-variation-settings: 'FILL' 1;
}

/* Hero 图标展示 */
.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeUp 0.6s 0.15s ease both;
}

.app-icon-stage {
  position: relative;
  width: 260px;
  height: 260px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.app-icon-stage::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 50%, color-mix(in srgb, var(--blue) 12%, transparent) 0%, transparent 70%);
  border-radius: 50%;
  animation: pulse 4s ease-in-out infinite;
  transition: var(--transition-theme);
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 0.8; }
  50% { transform: scale(1.08); opacity: 1; }
}

.app-icon-card {
  position: relative;
  width: 168px;
  height: 168px;
  background: var(--surface-card);
  border-radius: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-elevated);
  animation: float 3.5s ease-in-out infinite;
  transition: var(--transition-theme);
  overflow: hidden;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-14px); }
}

.app-icon-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.app-icon-fallback {
  display: none;
  width: 112px;
  height: 112px;
  background: var(--blue-light);
  border-radius: 30px;
  align-items: center;
  justify-content: center;
  position: relative;
}

.app-icon-fallback .material-symbols-outlined {
  font-size: 58px;
  color: var(--blue);
  font-variation-settings: 'FILL' 1, 'wght' 500;
}

/* ===== 通用区块 ===== */
.section-header {
  text-align: center;
  margin-bottom: 44px;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.8px;
  color: var(--text);
  margin-bottom: 10px;
}

.section-sub {
  font-size: 1rem;
  color: var(--text-sub);
  max-width: 480px;
  margin: 0 auto;
  line-height: 1.6;
}

/* ===== 截图轮换区域 ===== */
.screenshots {
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px 24px 72px;
}

.screenshot-viewer {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 28px;
}

.screenshot-frame {
  position: relative;
  width: 280px;
  height: 560px;
  background: var(--surface-card);
  border-radius: 40px;
  padding: 12px;
  box-shadow: var(--shadow-elevated);
  border: 1px solid var(--outline);
  overflow: hidden;
  transition: transform 0.3s ease, var(--transition-theme);
}

.screenshot-frame:hover {
  transform: translateY(-4px);
}

.screenshot-screen {
  width: 100%;
  height: 100%;
  border-radius: 30px;
  overflow: hidden;
  position: relative;
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-theme);
}

.carousel-track {
  display: flex;
  width: 100%;
  height: 100%;
  transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.carousel-slide {
  flex: 0 0 100%;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.carousel-slide img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  border-radius: 30px;
}

.slide-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  background: linear-gradient(180deg, var(--blue-soft) 0%, var(--surface) 100%);
  color: var(--text-muted);
  border-radius: 30px;
  transition: var(--transition-theme);
}

.slide-placeholder .material-symbols-outlined {
  font-size: 56px;
  color: var(--blue-light);
  font-variation-settings: 'FILL' 1;
}

.slide-placeholder span {
  font-size: 0.8rem;
  font-weight: 500;
}

.screenshot-dots {
  display: flex;
  gap: 10px;
  align-items: center;
}

.screenshot-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--outline);
  border: none;
  cursor: pointer;
  padding: 0;
  transition: all 0.3s ease;
}

.screenshot-dot.active {
  width: 24px;
  border-radius: 100px;
  background: var(--blue);
}

.screenshot-empty {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  color: var(--text-muted);
  padding: 24px;
  text-align: center;
}

.screenshot-empty .material-symbols-outlined {
  font-size: 64px;
  color: var(--blue-light);
  font-variation-settings: 'FILL' 1;
}

.screenshot-empty p {
  font-size: 0.85rem;
  line-height: 1.6;
}

.screenshot-empty code {
  background: var(--blue-soft);
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 0.78rem;
  color: var(--blue);
}

/* ===== 软件优势区域 ===== */
.advantages {
  max-width: 1100px;
  margin: 0 auto;
  padding: 40px 24px 80px;
}

.advantage-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
}

.advantage-card {
  background: var(--surface-card);
  border-radius: 24px;
  padding: 32px 28px;
  border: 1px solid var(--outline);
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease, var(--transition-theme);
  display: flex;
  gap: 18px;
  align-items: flex-start;
}

.advantage-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
  border-color: var(--blue-light);
}

.advantage-icon {
  width: 52px;
  height: 52px;
  background: var(--blue-soft);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background 0.25s ease, var(--transition-theme);
}

.advantage-card:hover .advantage-icon {
  background: var(--blue-light);
}

.advantage-icon .material-symbols-outlined {
  font-size: 28px;
  color: var(--blue);
  font-variation-settings: 'FILL' 1;
}

.advantage-body {
  flex: 1;
}

.advantage-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
  letter-spacing: -0.2px;
}

.advantage-desc {
  font-size: 0.875rem;
  color: var(--text-sub);
  line-height: 1.65;
}

/* ===== QQ 群区域 ===== */
.qq-groups {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px 96px;
}

.qq-card {
  background: var(--surface-card);
  border-radius: 28px;
  padding: 48px 40px;
  border: 1px solid var(--outline);
  transition: var(--transition-theme);
  overflow: hidden;
  box-sizing: border-box;
}

.qq-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 32px;
}

.qq-header-icon {
  width: 52px;
  height: 52px;
  background: var(--blue-soft);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: var(--transition-theme);
}

.qq-header-icon .material-symbols-outlined {
  font-size: 28px;
  color: var(--blue);
  font-variation-settings: 'FILL' 1;
}

.qq-header-text {
  flex: 1;
  min-width: 0;
}

.qq-header-text h3 {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.4px;
  margin-bottom: 4px;
}

.qq-header-text p {
  font-size: 0.88rem;
  color: var(--text-sub);
}

.qq-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}

.qq-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 18px;
  background: var(--surface);
  border-radius: 18px;
  border: 1px solid transparent;
  transition: background 0.2s, border-color 0.2s, transform 0.15s, var(--transition-theme);
  min-width: 0;
  box-sizing: border-box;
  overflow: hidden;
}

.qq-item:hover {
  background: var(--blue-soft);
  border-color: var(--blue-light);
  transform: translateY(-2px);
}

.qq-item-icon {
  width: 44px;
  height: 44px;
  background: var(--blue-soft);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: var(--transition-theme);
}

.qq-item:hover .qq-item-icon {
  background: var(--blue-light);
}

.qq-item-icon .material-symbols-outlined {
  font-size: 22px;
  color: var(--blue);
  font-variation-settings: 'FILL' 1;
}

.qq-item-info {
  flex: 1;
  min-width: 0;
  overflow: hidden;
}

.qq-item-label {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.qq-item-number {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
  font-family: 'Roboto Mono', 'Roboto', monospace;
  letter-spacing: 0.3px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.qq-item-actions {
  display: flex;
  gap: 4px;
  flex-shrink: 0;
}

.qq-action {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-sub);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, color 0.2s;
  text-decoration: none;
  flex-shrink: 0;
}

.qq-action:hover {
  background: var(--blue-light);
  color: var(--blue);
}

.qq-action .material-symbols-outlined {
  font-size: 18px;
  font-variation-settings: 'FILL' 1;
}

/* ===== 复制提示 ===== */
.copy-toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--text);
  color: var(--surface);
  padding: 12px 24px;
  border-radius: 100px;
  font-size: 0.88rem;
  font-weight: 500;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, transform 0.3s, visibility 0.3s;
  z-index: 2000;
  display: flex;
  align-items: center;
  gap: 8px;
}

.copy-toast.show {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.copy-toast .material-symbols-outlined {
  font-size: 20px;
  font-variation-settings: 'FILL' 1;
}

/* ===== 下载区域 ===== */
.download-section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px 96px;
}

.download-card {
  background: linear-gradient(135deg, var(--blue) 0%, var(--blue-dark) 100%);
  border-radius: 32px;
  padding: 56px 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
  transition: var(--transition-theme);
}

[data-theme="dark"] .download-card {
  background: linear-gradient(135deg, #1E3A5F 0%, #0F2339 100%);
}

.download-card::before {
  content: '';
  position: absolute;
  top: -60%;
  right: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.12) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.download-card::after {
  content: '';
  position: absolute;
  bottom: -50%;
  left: -5%;
  width: 320px;
  height: 320px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.download-content {
  position: relative;
  z-index: 1;
}

.download-title {
  font-size: 1.85rem;
  font-weight: 700;
  color: #fff;
  letter-spacing: -0.6px;
  margin-bottom: 10px;
}

.download-sub {
  font-size: 0.95rem;
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: 32px;
  line-height: 1.6;
}

.download-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
}

.download-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 18px 40px;
  background: #fff;
  color: var(--blue);
  border: none;
  border-radius: 100px;
  font-family: inherit;
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: 0.2px;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.25s ease;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}

[data-theme="dark"] .download-btn {
  background: var(--blue);
  color: #111318;
}

.download-btn .material-symbols-outlined {
  font-size: 24px;
  font-variation-settings: 'FILL' 1;
}

.download-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.22);
}

.download-btn:active {
  transform: translateY(0) scale(0.98);
}

.tutorial-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 18px 32px;
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
  border: 1.5px solid rgba(255, 255, 255, 0.3);
  border-radius: 100px;
  font-family: inherit;
  font-size: 1.05rem;
  font-weight: 500;
  letter-spacing: 0.2px;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.15s ease, border-color 0.2s;
}

.tutorial-btn:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: rgba(255, 255, 255, 0.5);
  transform: translateY(-2px);
}

.tutorial-btn:active {
  transform: translateY(0) scale(0.98);
}

.tutorial-btn .material-symbols-outlined {
  font-size: 22px;
  font-variation-settings: 'FILL' 1;
}

.download-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  margin-top: 28px;
  font-size: 0.82rem;
  color: rgba(255, 255, 255, 0.75);
  flex-wrap: wrap;
}

.download-meta span {
  display: flex;
  align-items: center;
  gap: 6px;
}

.download-meta .material-symbols-outlined {
  font-size: 16px;
}

/* ===== 赞助区域 ===== */
.sponsor-section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px 96px;
}

.sponsor-card {
  background: var(--surface-card);
  border-radius: 28px;
  padding: 48px 40px;
  border: 1px solid var(--outline);
  display: flex;
  align-items: center;
  gap: 48px;
  transition: var(--transition-theme);
}

.sponsor-info {
  flex: 1;
}

.sponsor-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--blue);
  background: var(--blue-soft);
  padding: 6px 14px;
  border-radius: 100px;
  margin-bottom: 20px;
  letter-spacing: 0.2px;
}

.sponsor-badge .material-symbols-outlined {
  font-size: 15px;
  font-variation-settings: 'FILL' 1;
}

.sponsor-title {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.5px;
  margin-bottom: 12px;
}

.sponsor-desc {
  font-size: 0.92rem;
  color: var(--text-sub);
  line-height: 1.7;
  margin-bottom: 24px;
  max-width: 400px;
}

.sponsor-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  background: var(--blue-soft);
  color: var(--blue);
  border: none;
  border-radius: 100px;
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s;
}

.sponsor-btn:hover {
  background: var(--blue-light);
  transform: translateY(-1px);
}

.sponsor-btn .material-symbols-outlined {
  font-size: 20px;
  font-variation-settings: 'FILL' 1;
}

.sponsor-qr {
  flex-shrink: 0;
  width: 180px;
  height: 180px;
  background: var(--surface);
  border-radius: 20px;
  border: 1px solid var(--outline);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  transition: var(--transition-theme);
  position: relative;
}

.sponsor-qr img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  padding: 12px;
}

.sponsor-qr-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  text-align: center;
  padding: 16px;
}

.sponsor-qr-placeholder .material-symbols-outlined {
  font-size: 40px;
  color: var(--blue-light);
  font-variation-settings: 'FILL' 1;
}

.sponsor-qr-placeholder span {
  font-size: 0.7rem;
  line-height: 1.4;
}

/* ===== 弹窗 ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: var(--overlay);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.3s;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--surface-card);
  border-radius: 28px;
  width: 100%;
  max-width: 560px;
  max-height: 80vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-elevated);
  transform: scale(0.9) translateY(20px);
  transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1), var(--transition-theme);
  border: 1px solid var(--outline);
}

.modal-overlay.active .modal {
  transform: scale(1) translateY(0);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 24px 28px 20px;
  border-bottom: 1px solid var(--outline);
  transition: var(--transition-theme);
}

.modal-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.3px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.modal-title .material-symbols-outlined {
  font-size: 24px;
  color: var(--blue);
  font-variation-settings: 'FILL' 1;
}

.modal-close {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-sub);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, color 0.2s;
}

.modal-close:hover {
  background: var(--blue-soft);
  color: var(--blue);
}

.modal-body {
  padding: 20px 28px 28px;
  overflow-y: auto;
  flex: 1;
}

/* ===== 教程列表 ===== */
.tutorial-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.tutorial-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 18px;
  background: var(--surface);
  border-radius: 16px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, transform 0.15s, var(--transition-theme);
  text-decoration: none;
  color: var(--text);
}

.tutorial-item:hover {
  background: var(--blue-soft);
  border-color: var(--blue-light);
  transform: translateX(4px);
}

.tutorial-item-icon {
  width: 44px;
  height: 44px;
  background: var(--blue-soft);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: var(--transition-theme);
}

.tutorial-item:hover .tutorial-item-icon {
  background: var(--blue-light);
}

.tutorial-item-icon .material-symbols-outlined {
  font-size: 22px;
  color: var(--blue);
  font-variation-settings: 'FILL' 1;
}

.tutorial-item-info {
  flex: 1;
  min-width: 0;
}

.tutorial-item-name {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.tutorial-item-meta {
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-top: 3px;
}

.tutorial-item-actions {
  display: flex;
  gap: 6px;
  flex-shrink: 0;
}

.tutorial-action {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-sub);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, color 0.2s;
  text-decoration: none;
}

.tutorial-action:hover {
  background: var(--blue-light);
  color: var(--blue);
}

.tutorial-action .material-symbols-outlined {
  font-size: 20px;
  font-variation-settings: 'FILL' 1;
}

/* ===== 弹窗空状态 ===== */
.modal-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 48px 24px;
  text-align: center;
  color: var(--text-muted);
}

.modal-empty .material-symbols-outlined {
  font-size: 56px;
  color: var(--blue-light);
  font-variation-settings: 'FILL' 1;
}

.modal-empty p {
  font-size: 0.85rem;
  line-height: 1.6;
}

.modal-empty code {
  background: var(--blue-soft);
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 0.78rem;
  color: var(--blue);
}

/* ===== 赞助弹窗 ===== */
.sponsor-modal-qr {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
  padding: 12px 0;
}

.sponsor-modal-qr-img {
  width: 260px;
  height: 260px;
  background: var(--surface);
  border-radius: 24px;
  border: 1px solid var(--outline);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  transition: var(--transition-theme);
}

.sponsor-modal-qr-img img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  padding: 16px;
}

.sponsor-modal-qr-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  color: var(--text-muted);
  text-align: center;
  padding: 20px;
}

.sponsor-modal-qr-placeholder .material-symbols-outlined {
  font-size: 56px;
  color: var(--blue-light);
  font-variation-settings: 'FILL' 1;
}

.sponsor-modal-qr-placeholder span {
  font-size: 0.8rem;
  line-height: 1.5;
}

.sponsor-modal-text {
  font-size: 0.9rem;
  color: var(--text-sub);
  text-align: center;
  line-height: 1.7;
  max-width: 340px;
}

/* ===== 页脚 ===== */
.footer {
  border-top: 1px solid var(--outline);
  padding: 28px 24px;
  text-align: center;
  transition: var(--transition-theme);
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-text {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 20px;
}

.footer-links a {
  font-size: 0.8rem;
  color: var(--text-sub);
  text-decoration: none;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: var(--blue);
}

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 48px;
    padding: 56px 24px 48px;
    text-align: center;
  }
  .hero-tagline {
    margin-left: auto;
    margin-right: auto;
  }
  .hero-actions {
    justify-content: center;
  }
  .hero-meta {
    justify-content: center;
  }
  .hero-visual {
    order: -1;
  }
  .app-icon-stage {
    width: 200px;
    height: 200px;
  }
  .app-icon-card {
    width: 140px;
    height: 140px;
    border-radius: 36px;
  }
  .advantage-grid {
    grid-template-columns: 1fr;
  }
  .qq-grid {
    grid-template-columns: 1fr;
  }
  .sponsor-card {
    flex-direction: column;
    text-align: center;
    gap: 32px;
  }
  .sponsor-desc {
    margin-left: auto;
    margin-right: auto;
  }
  .sponsor-qr {
    width: 160px;
    height: 160px;
  }
}

@media (max-width: 640px) {
  .nav-links {
    display: none;
  }
  .hero-title {
    font-size: 2.4rem;
  }
  .hero-tagline {
    font-size: 1rem;
  }
  .screenshot-frame {
    width: 240px;
    height: 480px;
  }
  .download-card {
    padding: 40px 24px;
    border-radius: 24px;
  }
  .download-title {
    font-size: 1.5rem;
  }
  .download-actions {
    flex-direction: column;
    width: 100%;
  }
  .download-btn, .tutorial-btn {
    width: 100%;
  }
  .download-meta {
    flex-wrap: wrap;
    gap: 12px;
  }
  .sponsor-card {
    padding: 32px 24px;
    border-radius: 24px;
  }
  .qq-card {
    padding: 28px 18px;
    border-radius: 22px;
  }
  .qq-header {
    flex-direction: column;
    text-align: center;
    gap: 12px;
    align-items: center;
  }
  .qq-item {
    padding: 14px 14px;
    gap: 10px;
  }
  .qq-item-icon {
    width: 38px;
    height: 38px;
    border-radius: 12px;
  }
  .qq-item-icon .material-symbols-outlined {
    font-size: 20px;
  }
  .qq-item-number {
    font-size: 0.82rem;
  }
  .qq-action {
    width: 32px;
    height: 32px;
  }
  .qq-action .material-symbols-outlined {
    font-size: 16px;
  }
  .footer-inner {
    justify-content: center;
    text-align: center;
  }
  .modal {
    max-height: 90vh;
  }
}
/* ===== 视频播放器 ===== */
.video-player {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.video-player-header {
  display: flex;
  align-items: center;
  gap: 12px;
}

.video-back {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 8px 14px;
  background: var(--blue-soft);
  color: var(--blue);
  border: none;
  border-radius: 100px;
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s;
  flex-shrink: 0;
}

.video-back:hover {
  background: var(--blue-light);
  transform: translateX(-2px);
}

.video-back .material-symbols-outlined {
  font-size: 18px;
  font-variation-settings: 'FILL' 1;
}

.video-player-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
}

.video-element {
  width: 100%;
  border-radius: 16px;
  background: #000;
  display: block;
  max-height: 400px;
  outline: none;
}

.video-player-actions {
  display: flex;
  justify-content: center;
}

.video-download-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: var(--blue);
  color: #fff;
  border-radius: 100px;
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  transition: background 0.2s, transform 0.15s;
}

[data-theme="dark"] .video-download-btn {
  color: #111318;
}

.video-download-btn:hover {
  background: var(--blue-dark);
  transform: translateY(-1px);
}

.video-download-btn .material-symbols-outlined {
  font-size: 20px;
  font-variation-settings: 'FILL' 1;
}