/* 错题小管家 - Apple风格官网 (基于 Pencil 设计) */

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

:root {
  --primary: #2BB6A3;
  --primary-light: #E8F7F5;
  --primary-dark: #25a393;
  --surface: #FFFFFF;
  --background: #FAFAFA;
  --text-primary: #1D1D1F;
  --text-secondary: #86868B;
  --text-tertiary: #AEAEB2;
  --border: #E5E5EA;
  --border-light: #F2F2F7;
  --success: #34C759;
  --warning: #FF9500;
  --error: #FF3B30;
  --blue: #007AFF;
  --purple: #AF52DE;
  --orange: #F5A623;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--background);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   Header
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-light);
  transition: all 0.3s;
}

.header.scrolled {
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.06);
}

.header-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 120px;
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: var(--primary);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.logo-icon i {
  width: 20px;
  height: 20px;
  color: white;
}

.logo-text {
  font-size: 20px;
  font-weight: 600;
  color: var(--text-primary);
}

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

.nav-link {
  font-size: 15px;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

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

.header-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

.login-link {
  font-size: 15px;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

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

.btn-primary-sm {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  font-size: 15px;
  font-weight: 600;
  color: white;
  background: var(--primary);
  border-radius: 100px;
  text-decoration: none;
  transition: all 0.2s;
}

.btn-primary-sm:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

.mobile-menu-btn {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--text-primary);
}

.mobile-menu-btn i {
  width: 24px;
  height: 24px;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  padding: 180px 0 80px;
  background: var(--background);
}

.hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 120px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 48px;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--primary-light);
  border-radius: 100px;
}

.hero-tag i {
  width: 14px;
  height: 14px;
  color: var(--primary);
}

.hero-tag span {
  font-size: 13px;
  font-weight: 500;
  color: var(--primary);
}

.hero-title {
  font-size: 64px;
  font-weight: 700;
  color: var(--text-primary);
  text-align: center;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: 20px;
  color: var(--text-secondary);
  text-align: center;
  line-height: 1.6;
  max-width: 700px;
}

.hero-cta {
  display: flex;
  align-items: center;
  gap: 16px;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 16px 32px;
  font-size: 17px;
  font-weight: 600;
  color: white;
  background: var(--primary);
  border-radius: 100px;
  text-decoration: none;
  transition: all 0.2s;
}

.btn-primary i {
  width: 18px;
  height: 18px;
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(43, 182, 163, 0.3);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 16px 32px;
  font-size: 17px;
  font-weight: 500;
  color: var(--text-primary);
  background: transparent;
  border: 1.5px solid var(--border);
  border-radius: 100px;
  text-decoration: none;
  transition: all 0.2s;
}

.btn-outline i {
  width: 16px;
  height: 16px;
}

.btn-outline:hover {
  border-color: var(--text-secondary);
  background: var(--surface);
}

/* Product Mockup */
.product-mockup {
  width: 100%;
  max-width: 1000px;
  background: var(--surface);
  border-radius: 16px;
  border: 1px solid var(--border-light);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.07);
  overflow: hidden;
}

.mockup-header {
  padding: 0 20px;
  height: 48px;
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--border-light);
}

.mockup-dots {
  display: flex;
  gap: 8px;
}

.mockup-dots .dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.mockup-dots .dot.red { background: #FF5F57; }
.mockup-dots .dot.yellow { background: #FEBC2E; }
.mockup-dots .dot.green { background: #28C840; }

.mockup-body {
  display: flex;
  height: 500px;
}

.mockup-sidebar {
  width: 200px;
  padding: 16px;
  background: var(--background);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.sidebar-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 14px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.sidebar-item i {
  width: 18px;
  height: 18px;
}

.sidebar-item.active {
  background: var(--primary-light);
  color: var(--primary);
}

.sidebar-item:hover:not(.active) {
  background: var(--border-light);
}

.mockup-main {
  flex: 1;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  background: var(--surface);
  border-left: 1px solid var(--border-light);
}

.mockup-main-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.main-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
}

.main-date {
  font-size: 14px;
  color: var(--text-tertiary);
}

.mockup-stats {
  display: flex;
  gap: 16px;
}

.stat-box {
  flex: 1;
  padding: 20px;
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.stat-box.teal { background: var(--primary-light); }
.stat-box.orange { background: #FFF8E6; }
.stat-box.blue { background: #F0F7FF; }

.stat-num {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
}

.stat-label {
  font-size: 13px;
  color: var(--text-secondary);
}

.mockup-chart {
  flex: 1;
  padding: 20px;
  background: var(--background);
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.chart-title {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
}

.chart-bars {
  flex: 1;
  display: flex;
  align-items: flex-end;
  gap: 24px;
  padding: 0 20px;
}

.bar-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.bar-item .bar {
  width: 100%;
  max-width: 40px;
  background: linear-gradient(180deg, var(--primary) 0%, #1a9a89 100%);
  border-radius: 4px 4px 0 0;
  min-height: 20px;
}

.bar-item span {
  font-size: 12px;
  color: var(--text-secondary);
}

/* Trust Bar */
.trust-bar {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 40px 0;
}

.trust-label {
  font-size: 14px;
  color: var(--text-tertiary);
}

.trust-items {
  display: flex;
  gap: 32px;
}

.trust-items span {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
}

/* ============================================
   Features Section
   ============================================ */
.features {
  padding: 100px 0;
  background: var(--surface);
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-tag {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--primary);
  letter-spacing: 2px;
  margin-bottom: 16px;
}

.section-title {
  font-size: 40px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 16px;
}

.section-desc {
  font-size: 18px;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 600px;
  margin: 0 auto;
}

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

.feature-card {
  padding: 32px;
  background: var(--background);
  border: 1px solid var(--border-light);
  border-radius: 20px;
  transition: all 0.3s;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.feature-icon i {
  width: 28px;
  height: 28px;
}

.feature-icon.teal {
  background: var(--primary-light);
  color: var(--primary);
}

.feature-icon.orange {
  background: #FFF8E6;
  color: var(--orange);
}

.feature-icon.blue {
  background: #F0F7FF;
  color: var(--blue);
}

.feature-icon.purple {
  background: #F5F0FF;
  color: var(--purple);
}

.feature-title {
  font-size: 20px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.feature-desc {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ============================================
   How It Works
   ============================================ */
.how-it-works {
  padding: 100px 0;
  background: var(--background);
}

.steps {
  display: flex;
  gap: 48px;
}

.step {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 24px;
}

.step-num {
  width: 64px;
  height: 64px;
  background: var(--primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  font-weight: 700;
  color: white;
}

.step-title {
  font-size: 22px;
  font-weight: 600;
  color: var(--text-primary);
}

.step-desc {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 300px;
}

/* ============================================
   CTA Section
   ============================================ */
.cta-section {
  padding: 100px 0;
  background: var(--primary);
  text-align: center;
}

.cta-title {
  font-size: 44px;
  font-weight: 700;
  color: white;
  margin-bottom: 16px;
}

.cta-subtitle {
  font-size: 20px;
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: 32px;
}

.cta-buttons {
  display: flex;
  justify-content: center;
  gap: 16px;
}

.btn-white {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 18px 36px;
  font-size: 18px;
  font-weight: 600;
  color: var(--primary);
  background: white;
  border-radius: 100px;
  text-decoration: none;
  transition: all 0.2s;
}

.btn-white i {
  width: 20px;
  height: 20px;
}

.btn-white:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.btn-outline-white {
  display: inline-flex;
  align-items: center;
  padding: 18px 36px;
  font-size: 18px;
  font-weight: 500;
  color: white;
  background: transparent;
  border: 2px solid white;
  border-radius: 100px;
  text-decoration: none;
  transition: all 0.2s;
}

.btn-outline-white:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  padding: 60px 0 40px;
  background: var(--text-primary);
}

.footer-main {
  display: flex;
  justify-content: space-between;
  margin-bottom: 48px;
}

.footer-brand {
  max-width: 300px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  margin-bottom: 16px;
}

.footer-logo-icon {
  width: 32px;
  height: 32px;
  background: var(--primary);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.footer-logo-icon i {
  width: 18px;
  height: 18px;
  color: white;
}

.footer-logo span {
  font-size: 18px;
  font-weight: 600;
  color: white;
}

.footer-tagline {
  font-size: 14px;
  color: rgba(255, 255, 255, 0.6);
  line-height: 1.6;
}

.footer-links {
  display: flex;
  gap: 80px;
}

.footer-col h4 {
  font-size: 14px;
  font-weight: 600;
  color: white;
  margin-bottom: 16px;
}

.footer-col a {
  display: block;
  font-size: 14px;
  color: rgba(255, 255, 255, 0.6);
  text-decoration: none;
  margin-bottom: 12px;
  transition: color 0.2s;
}

.footer-col a:hover {
  color: white;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  margin-bottom: 16px;
}

.footer-bottom p {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.4);
}

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

.footer-social span {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.4);
}

.footer-icp {
  text-align: center;
}

.footer-icp a {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.4);
  text-decoration: none;
}

.footer-icp a:hover {
  color: rgba(255, 255, 255, 0.6);
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 1024px) {
  .header-content {
    padding: 0 24px;
  }

  .hero-inner {
    padding: 0 24px;
  }

  .hero-title {
    font-size: 48px;
  }

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

  .steps {
    flex-direction: column;
    gap: 48px;
  }

  .footer-main {
    flex-direction: column;
    gap: 48px;
  }
}

@media (max-width: 768px) {
  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--surface);
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    border-bottom: 1px solid var(--border);
  }

  .nav.active {
    display: flex;
  }

  .header-right {
    display: none;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .hero {
    padding: 120px 0 60px;
  }

  .hero-title {
    font-size: 36px;
  }

  .hero-subtitle {
    font-size: 16px;
  }

  .hero-cta {
    flex-direction: column;
    width: 100%;
  }

  .btn-primary,
  .btn-outline {
    width: 100%;
    justify-content: center;
  }

  .product-mockup {
    display: none;
  }

  .trust-items {
    flex-direction: column;
    gap: 12px;
  }

  .section-title {
    font-size: 28px;
  }

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

  .cta-title {
    font-size: 28px;
  }

  .cta-buttons {
    flex-direction: column;
  }

  .btn-white,
  .btn-outline-white {
    width: 100%;
    justify-content: center;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }

  .footer-social {
    flex-wrap: wrap;
    justify-content: center;
  }
}

/* ============================================
   Login Modal
   ============================================ */
.login-modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(8px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
}

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

.login-modal {
  width: 100%;
  max-width: 420px;
  background: var(--surface);
  border-radius: 24px;
  padding: 40px;
  position: relative;
  transform: translateY(20px) scale(0.95);
  transition: all 0.3s ease;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

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

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--background);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  color: var(--text-secondary);
  transition: all 0.2s;
}

.modal-close:hover {
  background: var(--border-light);
  color: var(--text-primary);
}

.modal-close i {
  width: 20px;
  height: 20px;
}

.modal-header {
  text-align: center;
  margin-bottom: 32px;
}

.modal-logo {
  width: 56px;
  height: 56px;
  background: var(--primary);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
}

.modal-logo i {
  width: 28px;
  height: 28px;
  color: white;
}

.modal-title {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.modal-subtitle {
  font-size: 15px;
  color: var(--text-secondary);
}

.login-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.form-error {
  background: #FEE2E2;
  color: #DC2626;
  padding: 12px 16px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 500;
  text-align: center;
  display: none;
}

.form-error.show {
  display: block;
  animation: shake 0.3s ease;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-8px); }
  75% { transform: translateX(8px); }
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.form-label {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
}

.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  background: #F5F5F7;
  border: 1.5px solid transparent;
  border-radius: 12px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.input-wrapper:hover {
  background: #EFEFEF;
}

.input-wrapper:focus-within {
  background: var(--surface);
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(43, 182, 163, 0.12);
  transform: translateY(-1px);
}

.input-wrapper > i:first-of-type {
  position: absolute;
  left: 18px;
  width: 18px;
  height: 18px;
  color: #AEAEB2;
  pointer-events: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 1;
}

.input-wrapper:focus-within > i:first-of-type {
  color: var(--primary);
  transform: scale(1.1);
}

.input-wrapper input {
  width: 100%;
  height: 52px;
  padding: 0 16px 0 50px;
  font-size: 15px;
  font-family: inherit;
  color: var(--text-primary);
  background: transparent;
  border: none;
  border-radius: 12px;
  outline: none;
  transition: all 0.2s;
}

.input-wrapper input::placeholder {
  color: #C7C7CC;
}

.toggle-password {
  position: absolute;
  right: 12px;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--text-tertiary);
  transition: color 0.2s;
}

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

.toggle-password i {
  width: 20px;
  height: 20px;
}

.form-options {
  display: flex;
  align-items: center;
}

.checkbox-wrapper {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  user-select: none;
  font-size: 14px;
  color: var(--text-secondary);
}

.checkbox-wrapper input {
  display: none;
}

.checkbox-mark {
  width: 20px;
  height: 20px;
  border: 1.5px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  position: relative;
  transition: all 0.2s;
}

.checkbox-mark::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 6px;
  width: 5px;
  height: 10px;
  border: 2px solid white;
  border-top: none;
  border-left: none;
  transform: rotate(45deg) scale(0);
  transition: transform 0.2s;
}

.checkbox-wrapper input:checked + .checkbox-mark {
  background: var(--primary);
  border-color: var(--primary);
}

.checkbox-wrapper input:checked + .checkbox-mark::after {
  transform: rotate(45deg) scale(1);
}

.btn-submit {
  width: 100%;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: var(--primary);
  color: white;
  font-size: 16px;
  font-weight: 600;
  font-family: inherit;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.2s;
  margin-top: 8px;
}

.btn-submit:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(43, 182, 163, 0.3);
}

.btn-submit:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-submit i {
  width: 18px;
  height: 18px;
}

@media (max-width: 480px) {
  .login-modal {
    padding: 32px 24px;
    border-radius: 20px;
  }

  .modal-title {
    font-size: 20px;
  }

  .input-wrapper input {
    height: 48px;
    font-size: 14px;
  }

  .btn-submit {
    height: 48px;
    font-size: 15px;
  }
}