@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;900&display=swap');

:root {
  /* Colors */
  --color-primary: #2563EB;
  --color-primary-hover: #1D4ED8;
  --color-secondary: #8B5CF6;
  --color-text-primary: #18181B;
  --color-text-secondary: #71717A;
  --color-text-tertiary: #64748B;
  --color-text-light: #94A3B8;
  --color-text-disabled: #E2E8F0;
  --color-bg-primary: #FAFBFC;
  --color-bg-secondary: #F8FAFC;
  --color-bg-white: #FFFFFF;
  --color-border: #E5E7EB;
  --color-border-light: #E2E8F0;
  --color-border-lighter: #CBD5E1;
  --color-footer-bg: #0B1220;
  --color-footer-text: #E2E8F0;
  
  /* Spacing */
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 40px;
  --spacing-3xl: 48px;
  --spacing-4xl: 60px;
  --spacing-5xl: 80px;
  --spacing-6xl: 120px;
  
  /* Border Radius */
  --radius-sm: 12px;
  --radius-md: 14px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-2xl: 24px;
  --radius-3xl: 28px;
  
  /* Shadows */
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 6px 16px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 0 16px rgba(0, 0, 0, 0.05);
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  height: 100%;
  font-family: var(--font-family);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--color-primary);
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  transition: all 0.2s ease;
}

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

/* Utility Classes */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 140px;
}

@media (max-width: 1440px) {
  .container {
    padding: 0 80px;
  }
}

@media (max-width: 1024px) {
  .container {
    padding: 0 40px;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 20px;
  }
}

/* Button Styles */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--color-primary);
  color: white;
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--color-primary);
  color: var(--color-primary);
}

.btn-outline:hover {
  background-color: var(--color-primary);
  color: white;
}

.btn-secondary {
  background-color: var(--color-bg-secondary);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border-light);
}

.btn-secondary:hover {
  background-color: var(--color-bg-white);
}

/* Hero 级主按钮：用于首页 / 乐理 / 练习页面的主行动 */
.btn-hero {
  padding: 16px 28px;
  font-size: 16px;
  font-weight: 600;
  border-radius: 14px;
}

/* Card Styles */
.card {
  background-color: var(--color-bg-white);
  border-radius: var(--radius-3xl);
  padding: 36px 40px;
  box-shadow: var(--shadow-lg);
}

.card-sm {
  padding: 24px;
  border-radius: var(--radius-2xl);
}

/* Text Styles */
.text-primary {
  color: var(--color-text-primary);
}

.text-secondary {
  color: var(--color-text-secondary);
}

.text-tertiary {
  color: var(--color-text-tertiary);
}

.text-light {
  color: var(--color-text-light);
}

/* ===== Shared Page Layout Patterns (Home + Theory + Practice) ===== */

/* 统一各页面 Hero 主标题 / 副标题基础风格（具体字号在各页面细调） */
.page-hero-title {
  font-weight: 800;
  line-height: 1.1;
  text-align: center;
  color: var(--color-text-primary);
}

.page-hero-subtitle {
  font-weight: 400;
  text-align: center;
  color: var(--color-text-secondary);
  margin-top: 8px;
}

/* 统一“概览状态条”底板风格：乐理 overview / 练习中心 / 练习工具页顶部 strip */
.status-bar {
  background: #F8FAFC;
  border-radius: 16px;
  border: 1px solid #E2E8F0;
  padding: 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.status-bar-line {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.status-bar-item {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  font-size: 13px;
  color: #64748B;
}

.status-bar-item .k {
  font-weight: 500;
}

.status-bar-item .v {
  font-weight: 600;
  color: #0F172A;
}

.status-bar-item--grow {
  flex: 1;
  min-width: 220px;
}

.status-bar-cta {
  white-space: nowrap;
}

/* Layout Utilities */
.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.items-center {
  align-items: center;
}

.justify-center {
  justify-content: center;
}

.justify-between {
  justify-content: space-between;
}

.gap-sm {
  gap: var(--spacing-sm);
}

.gap-md {
  gap: var(--spacing-md);
}

.gap-lg {
  gap: var(--spacing-lg);
}

.gap-xl {
  gap: var(--spacing-xl);
}

.gap-2xl {
  gap: var(--spacing-2xl);
}

/* Spacing Utilities */
.p-sm { padding: var(--spacing-sm); }
.p-md { padding: var(--spacing-md); }
.p-lg { padding: var(--spacing-lg); }
.p-xl { padding: var(--spacing-xl); }

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

/* Header */
.header {
  background-color: var(--color-bg-white);
  border-bottom: 1px solid var(--color-border);
  height: 88px;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header .container{
  height: 100%;
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: 40px;
}

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

.logo-link {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--color-text-primary);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: -0.03em;
  transition: color 0.2s ease;
}

.logo-link:hover {
  color: var(--color-primary);
}

.logo-icon {
  display: block;
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  object-fit: contain;
  border-radius: 10px;
  box-shadow: 0 2px 12px rgba(37, 99, 235, 0.15);
  transition: box-shadow 0.2s ease;
}

.logo-link:hover .logo-icon {
  box-shadow: 0 4px 16px rgba(37, 99, 235, 0.2);
}

.logo-text {
  font-weight: 700;
  letter-spacing: -0.02em;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 40px;
}

.nav-link {
  color: #6B7280;
  font-size: 16px;
  font-weight: 500;
  transition: color 0.2s ease;
}

.nav-link:hover,
.nav-link.active {
  color: #2563EB;
  font-weight: 600;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 20px;
}

.btn-auth{
  padding: 12px 24px;
  border-radius: 12px;
  font-weight: 600;
}

.header-actions .btn-outline{
  border-width: 1.5px;
}

@media (max-width: 768px) {
  .header-nav {
    display: flex;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    gap: 20px;
  }
  
  .header-nav::-webkit-scrollbar {
    display: none;
  }
  
  .nav-link {
    white-space: nowrap;
    padding: 8px 16px;
    font-size: 14px;
  }
  
  .header-actions {
    gap: 12px;
  }
  
  .btn {
    padding: 8px 16px;
    font-size: 13px;
  }
}

/* Footer */
.footer {
  background-color: var(--color-footer-bg);
  color: var(--color-footer-text);
  padding: 60px 0;
  margin-top: auto;
}

.footer-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.footer-brand{
  font-size: 16px;
  font-weight: 700;
  color: var(--color-footer-text);
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 16px;
}

.footer-link {
  color: #94A3B8;
  font-size: 13px;
  font-weight: 600;
  transition: color 0.2s ease;
}

.footer-link:hover {
  color: var(--color-footer-text);
}

.footer-copyright {
  font-size: 12px;
  font-weight: 500;
  color: #64748B;
}

/* 移动端菜单栏优化 */
@media (max-width: 768px) {
  .header-nav {
    display: flex;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }
  
  .header-nav::-webkit-scrollbar {
    display: none;
  }
  
  .nav-link {
    white-space: nowrap;
    padding: 8px 16px;
    font-size: 14px;
  }

  .footer-content {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .footer-links {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 12px 16px;
  }
}