/* ============================================
   青春旋律 - 清新校园/Vlog风 主样式表
   CSS/ID前缀: ym-
   配色: 薄荷绿 #84fab0 / 天空蓝 #8fd3f4 / 樱花粉 #fbc2eb
   ============================================ */

/* --- Google Fonts Import --- */
@import url('https://fonts.googleapis.com/css2?family=ZCOOL+KuaiLe&family=Noto+Sans+SC:wght@300;400;500;700&display=swap');

/* --- CSS Variables --- */
:root {
  --ym-primary: #84fab0;
  --ym-secondary: #8fd3f4;
  --ym-accent: #fbc2eb;
  --ym-text: #333333;
  --ym-link: #a18cd1;
  --ym-white: #ffffff;
  --ym-light-bg: #f8fffe;
  --ym-card-shadow: 0 4px 16px rgba(132, 250, 176, 0.15);
  --ym-font-title: 'ZCOOL KuaiLe', cursive;
  --ym-font-body: 'Noto Sans SC', sans-serif;
  --ym-radius: 12px;
  --ym-radius-lg: 20px;
  --ym-transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--ym-font-body);
  color: var(--ym-text);
  background-color: var(--ym-light-bg);
  line-height: 1.8;
  overflow-x: hidden;
}

a {
  color: var(--ym-link);
  text-decoration: none;
  transition: var(--ym-transition);
}

a:hover {
  color: #8a6fbf;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--ym-font-title);
  line-height: 1.4;
  color: var(--ym-text);
}

/* --- Jammer Block (Hidden) --- */
.jammer-block {
  display: none;
}

/* --- Header / Navigation --- */
#ym-header {
  width: 100%;
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(132, 250, 176, 0.2);
  z-index: 100;
  /* 禁止sticky/fixed */
  position: relative;
}

.ym-nav-inner {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.ym-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--ym-font-title);
  font-size: 1.4rem;
  color: var(--ym-text);
}

.ym-logo img {
  width: 40px;
  height: 40px;
  transition: transform 0.3s ease;
}

.ym-logo:hover img {
  transform: rotate(15deg);
}

.ym-nav-links {
  display: flex;
  list-style: none;
  gap: 8px;
}

.ym-nav-links li a {
  display: inline-block;
  padding: 8px 16px;
  font-size: 0.95rem;
  color: var(--ym-text);
  border-radius: var(--ym-radius);
  transition: var(--ym-transition);
  font-weight: 500;
}

.ym-nav-links li a:hover,
.ym-nav-links li a.ym-active {
  color: var(--ym-link);
  background: rgba(161, 140, 209, 0.08);
  transform: scale(1.05);
}

/* Hamburger Menu */
.ym-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  z-index: 200;
}

.ym-hamburger span {
  width: 26px;
  height: 3px;
  background: var(--ym-text);
  border-radius: 3px;
  transition: var(--ym-transition);
}

.ym-hamburger.ym-open span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 6px);
}

.ym-hamburger.ym-open span:nth-child(2) {
  opacity: 0;
}

.ym-hamburger.ym-open span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -6px);
}

/* Mobile Sidebar */
.ym-mobile-nav {
  position: fixed;
  top: 0;
  right: -300px;
  width: 280px;
  height: 100vh;
  background: var(--ym-white);
  box-shadow: -4px 0 24px rgba(0,0,0,0.1);
  z-index: 150;
  transition: right 0.35s ease;
  padding: 80px 24px 24px;
  overflow-y: auto;
}

.ym-mobile-nav.ym-open {
  right: 0;
}

.ym-mobile-nav a {
  display: block;
  padding: 14px 0;
  font-size: 1.05rem;
  color: var(--ym-text);
  border-bottom: 1px solid rgba(0,0,0,0.06);
}

.ym-mobile-nav a:hover {
  color: var(--ym-link);
  padding-left: 8px;
}

.ym-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.3);
  z-index: 140;
  opacity: 0;
  visibility: hidden;
  transition: var(--ym-transition);
}

.ym-overlay.ym-open {
  opacity: 1;
  visibility: visible;
}

/* --- Section Common --- */
.ym-section {
  padding: 60px 24px;
  max-width: 1440px;
  margin: 0 auto;
}

.ym-section-title {
  font-size: 2rem;
  text-align: center;
  margin-bottom: 12px;
  background: linear-gradient(135deg, var(--ym-primary), var(--ym-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.ym-section-subtitle {
  text-align: center;
  color: #888;
  font-size: 1rem;
  margin-bottom: 40px;
}

/* --- Hero Banner --- */
#ym-hero {
  position: relative;
  width: 100%;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: linear-gradient(135deg, #84fab0 0%, #8fd3f4 50%, #fbc2eb 100%);
}

.ym-hero-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.3;
}

.ym-hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 40px 24px;
  animation: ym-slideUp 0.8s ease-out;
}

.ym-hero-slogan {
  font-family: var(--ym-font-title);
  font-size: 3rem;
  color: var(--ym-white);
  text-shadow: 0 2px 12px rgba(0,0,0,0.15);
  margin-bottom: 16px;
}

.ym-hero-desc {
  font-size: 1.2rem;
  color: rgba(255,255,255,0.9);
  margin-bottom: 32px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.ym-hero-btn {
  display: inline-block;
  padding: 14px 40px;
  background: var(--ym-white);
  color: var(--ym-link);
  font-size: 1.1rem;
  font-weight: 700;
  border-radius: 50px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.1);
  transition: var(--ym-transition);
}

.ym-hero-btn:hover {
  transform: scale(1.08);
  box-shadow: 0 6px 28px rgba(0,0,0,0.15);
  color: var(--ym-link);
}

/* --- Card Styles (Polaroid Effect) --- */
.ym-card {
  background: var(--ym-white);
  border-radius: var(--ym-radius);
  padding: 16px;
  box-shadow: var(--ym-card-shadow);
  transition: var(--ym-transition);
  border: 6px solid var(--ym-white);
  overflow: hidden;
}

.ym-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 8px 32px rgba(132, 250, 176, 0.25);
}

.ym-card-img {
  width: 100%;
  aspect-ratio: 16/9;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: 12px;
}

.ym-card-title {
  font-size: 1.1rem;
  margin-bottom: 6px;
  font-family: var(--ym-font-title);
}

.ym-card-desc {
  font-size: 0.9rem;
  color: #666;
  line-height: 1.6;
}

.ym-card-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 10px;
  font-size: 0.8rem;
  color: #999;
}

/* --- Grid Layouts --- */
.ym-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

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

.ym-grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

/* --- Creator Rewards Section --- */
#ym-rewards {
  background: linear-gradient(135deg, rgba(132,250,176,0.08), rgba(143,211,244,0.08));
}

.ym-reward-number {
  font-family: var(--ym-font-title);
  font-size: 3.5rem;
  background: linear-gradient(135deg, var(--ym-primary), var(--ym-link));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-align: center;
  margin-bottom: 8px;
}

.ym-reward-label {
  text-align: center;
  color: #888;
  font-size: 0.95rem;
}

.ym-reward-stats {
  display: flex;
  justify-content: center;
  gap: 48px;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

/* --- Challenge Wall --- */
.ym-challenge-grid {
  columns: 3;
  column-gap: 20px;
}

.ym-challenge-item {
  break-inside: avoid;
  margin-bottom: 20px;
  background: var(--ym-white);
  border-radius: var(--ym-radius);
  overflow: hidden;
  box-shadow: var(--ym-card-shadow);
  transition: var(--ym-transition);
}

.ym-challenge-item:hover {
  transform: scale(1.02);
}

.ym-challenge-tag {
  display: inline-block;
  padding: 4px 12px;
  background: linear-gradient(135deg, var(--ym-accent), var(--ym-secondary));
  color: var(--ym-white);
  border-radius: 20px;
  font-size: 0.8rem;
  margin: 10px;
}

/* --- Top Creators --- */
.ym-creator-card {
  text-align: center;
  padding: 24px 16px;
}

.ym-creator-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  margin: 0 auto 12px;
  border: 3px solid var(--ym-primary);
  object-fit: cover;
}

.ym-creator-name {
  font-family: var(--ym-font-title);
  font-size: 1.1rem;
  margin-bottom: 4px;
}

.ym-creator-fans {
  font-size: 0.85rem;
  color: #999;
}

.ym-rank-badge {
  display: inline-block;
  width: 28px;
  height: 28px;
  line-height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--ym-primary), var(--ym-secondary));
  color: var(--ym-white);
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 8px;
}

/* --- Featured Videos --- */
.ym-featured-card {
  position: relative;
  border-radius: var(--ym-radius-lg);
  overflow: hidden;
}

.ym-featured-card .ym-play-icon {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 60px;
  height: 60px;
  background: rgba(255,255,255,0.85);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--ym-transition);
  z-index: 2;
}

.ym-featured-card:hover .ym-play-icon {
  transform: translate(-50%, -50%) scale(1.15);
  background: var(--ym-white);
}

.ym-play-icon::after {
  content: '';
  display: block;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 10px 0 10px 18px;
  border-color: transparent transparent transparent var(--ym-link);
  margin-left: 4px;
}

/* --- Upload Section --- */
#ym-upload {
  text-align: center;
  background: linear-gradient(135deg, var(--ym-accent) 0%, var(--ym-secondary) 100%);
  padding: 80px 24px;
  border-radius: 0;
}

#ym-upload .ym-section-title {
  color: var(--ym-white);
  -webkit-text-fill-color: var(--ym-white);
}

.ym-upload-btn {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 18px 48px;
  background: var(--ym-white);
  color: var(--ym-link);
  font-size: 1.2rem;
  font-weight: 700;
  border-radius: 50px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.12);
  transition: var(--ym-transition);
  cursor: pointer;
  border: none;
  font-family: var(--ym-font-title);
  margin-top: 24px;
}

.ym-upload-btn:hover {
  transform: scale(1.08) translateY(-2px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.18);
}

.ym-upload-icon {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--ym-primary), var(--ym-link));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--ym-white);
  font-size: 1.4rem;
  font-weight: 700;
}

/* --- APP Download --- */
#ym-app {
  background: linear-gradient(135deg, rgba(143,211,244,0.1), rgba(251,194,235,0.1));
}

.ym-app-wrap {
  display: flex;
  align-items: center;
  gap: 48px;
}

.ym-app-mockup {
  flex: 0 0 300px;
  position: relative;
}

.ym-app-mockup img {
  width: 100%;
  border-radius: 32px;
  box-shadow: 0 12px 48px rgba(0,0,0,0.12);
}

.ym-app-info {
  flex: 1;
}

.ym-app-info h2 {
  font-size: 2rem;
  margin-bottom: 16px;
}

.ym-app-info p {
  font-size: 1.05rem;
  color: #666;
  margin-bottom: 24px;
}

.ym-download-btns {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.ym-dl-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: var(--ym-transition);
}

.ym-dl-btn-ios {
  background: var(--ym-text);
  color: var(--ym-white);
}

.ym-dl-btn-android {
  background: var(--ym-primary);
  color: var(--ym-text);
}

.ym-dl-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.12);
}

/* --- Points Mall --- */
.ym-points-item {
  text-align: center;
  padding: 20px;
}

.ym-points-item img {
  width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: var(--ym-radius);
  margin: 0 auto 12px;
}

.ym-points-price {
  display: inline-block;
  padding: 4px 16px;
  background: linear-gradient(135deg, var(--ym-primary), var(--ym-secondary));
  color: var(--ym-white);
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-top: 8px;
}

.ym-exchange-btn {
  display: inline-block;
  margin-top: 10px;
  padding: 8px 24px;
  background: var(--ym-link);
  color: var(--ym-white);
  border-radius: 20px;
  font-size: 0.85rem;
  border: none;
  cursor: pointer;
  transition: var(--ym-transition);
}

.ym-exchange-btn:hover {
  background: #8a6fbf;
  transform: scale(1.05);
}

/* --- Campus Partner --- */
#ym-partner {
  background: linear-gradient(135deg, rgba(251,194,235,0.1), rgba(132,250,176,0.1));
}

.ym-partner-qa {
  max-width: 700px;
  margin: 0 auto;
}

.ym-partner-question {
  padding: 20px 24px;
  background: var(--ym-white);
  border-radius: var(--ym-radius);
  margin-bottom: 16px;
  box-shadow: var(--ym-card-shadow);
  cursor: pointer;
  transition: var(--ym-transition);
  font-size: 1.05rem;
  position: relative;
  padding-right: 48px;
}

.ym-partner-question::after {
  content: '→';
  position: absolute;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--ym-link);
  font-size: 1.2rem;
  transition: var(--ym-transition);
}

.ym-partner-question:hover {
  transform: translateX(6px);
  border-left: 3px solid var(--ym-link);
}

.ym-partner-question:hover::after {
  transform: translateY(-50%) translateX(4px);
}

/* --- About Us --- */
#ym-about {
  text-align: center;
}

.ym-about-text {
  max-width: 800px;
  margin: 0 auto 32px;
  font-size: 1.05rem;
  color: #555;
  line-height: 2;
}

/* --- Footer --- */
#ym-footer {
  background: var(--ym-text);
  color: rgba(255,255,255,0.7);
  padding: 48px 24px 24px;
}

.ym-footer-inner {
  max-width: 1440px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
  margin-bottom: 32px;
}

.ym-footer-col h4 {
  color: var(--ym-white);
  font-family: var(--ym-font-title);
  font-size: 1.1rem;
  margin-bottom: 16px;
}

.ym-footer-col a {
  display: block;
  color: rgba(255,255,255,0.6);
  padding: 4px 0;
  font-size: 0.9rem;
}

.ym-footer-col a:hover {
  color: var(--ym-primary);
  padding-left: 4px;
}

.ym-social-icons {
  display: flex;
  gap: 16px;
  margin-top: 8px;
}

.ym-social-icon {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: rgba(255,255,255,0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--ym-transition);
  font-size: 0.8rem;
  color: rgba(255,255,255,0.7);
}

.ym-social-icon:hover {
  background: var(--ym-primary);
  color: var(--ym-text);
  transform: scale(1.1);
}

.ym-footer-bottom {
  max-width: 1440px;
  margin: 0 auto;
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 20px;
  text-align: center;
  font-size: 0.85rem;
}

.ym-footer-bottom p {
  margin-bottom: 6px;
}

.ym-age-badge {
  display: inline-block;
  padding: 2px 10px;
  border: 1px solid rgba(255,255,255,0.3);
  border-radius: 4px;
  font-size: 0.8rem;
  margin-right: 8px;
}

/* --- Animations --- */
@keyframes ym-slideUp {
  from {
    opacity: 0;
    transform: translateY(40px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes ym-fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes ym-jelly {
  0% { transform: scale(1); }
  30% { transform: scale(1.15); }
  50% { transform: scale(0.92); }
  70% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

.ym-animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.ym-animate-on-scroll.ym-visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- Category / Inner Page --- */
.ym-page-header {
  background: linear-gradient(135deg, var(--ym-primary), var(--ym-secondary));
  padding: 60px 24px;
  text-align: center;
  color: var(--ym-white);
}

.ym-page-header h1 {
  font-size: 2.2rem;
  color: var(--ym-white);
  margin-bottom: 12px;
}

.ym-page-header p {
  font-size: 1.05rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto;
}

.ym-breadcrumb {
  padding: 16px 24px;
  max-width: 1440px;
  margin: 0 auto;
  font-size: 0.9rem;
  color: #999;
}

.ym-breadcrumb a {
  color: var(--ym-link);
}

.ym-breadcrumb span {
  margin: 0 8px;
  color: #ccc;
}

.ym-video-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  padding: 24px;
  max-width: 1440px;
  margin: 0 auto;
}

/* --- About / Policy Pages --- */
.ym-content-page {
  max-width: 900px;
  margin: 0 auto;
  padding: 48px 24px;
}

.ym-content-page h2 {
  font-size: 1.6rem;
  margin: 32px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--ym-primary);
}

.ym-content-page p {
  margin-bottom: 16px;
  line-height: 2;
}

.ym-content-page ul {
  margin: 16px 0;
  padding-left: 24px;
}

.ym-content-page ul li {
  margin-bottom: 8px;
  line-height: 1.8;
}

/* --- APP Download Page --- */
.ym-app-page-hero {
  background: linear-gradient(135deg, var(--ym-secondary), var(--ym-accent));
  padding: 80px 24px;
  text-align: center;
  color: var(--ym-white);
}

.ym-app-features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  padding: 60px 24px;
  max-width: 1200px;
  margin: 0 auto;
}

.ym-app-feature-card {
  text-align: center;
  padding: 32px 20px;
  background: var(--ym-white);
  border-radius: var(--ym-radius-lg);
  box-shadow: var(--ym-card-shadow);
  transition: var(--ym-transition);
}

.ym-app-feature-card:hover {
  transform: translateY(-8px);
}

.ym-app-feature-icon {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--ym-primary), var(--ym-secondary));
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
}

/* --- Responsive: Mobile First --- */
@media (max-width: 360px) {
  html { font-size: 14px; }
  .ym-hero-slogan { font-size: 1.8rem; }
}

@media (max-width: 768px) {
  .ym-nav-links { display: none; }
  .ym-hamburger { display: flex; }

  .ym-hero-slogan { font-size: 2rem; }
  .ym-hero-desc { font-size: 1rem; }

  .ym-grid-2,
  .ym-grid-3,
  .ym-grid-4 {
    grid-template-columns: 1fr;
  }

  .ym-challenge-grid {
    columns: 1;
  }

  .ym-video-list {
    grid-template-columns: 1fr;
  }

  .ym-footer-inner {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .ym-app-wrap {
    flex-direction: column;
    text-align: center;
  }

  .ym-app-mockup {
    flex: none;
    width: 200px;
  }

  .ym-download-btns {
    justify-content: center;
  }

  .ym-app-features {
    grid-template-columns: 1fr;
  }

  .ym-reward-stats {
    gap: 24px;
  }

  .ym-section { padding: 40px 16px; }
  .ym-section-title { font-size: 1.6rem; }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .ym-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .ym-challenge-grid {
    columns: 2;
  }

  .ym-video-list {
    grid-template-columns: repeat(2, 1fr);
  }

  .ym-app-features {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1025px) and (max-width: 1440px) {
  .ym-grid-4 {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* --- Utility --- */
.ym-text-center { text-align: center; }
.ym-mt-20 { margin-top: 20px; }
.ym-mb-20 { margin-bottom: 20px; }
.ym-gradient-text {
  background: linear-gradient(135deg, var(--ym-primary), var(--ym-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}