/* Component Styles - Compressed */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: var(--z-fixed);
    height: 80px;
    transition: all var(--transition-normal)
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding)
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
    text-decoration: none
}

.nav-logo img {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm)
}

.nav-buttons {
    display: flex;
    align-items: center;
    gap: var(--spacing-md)
}

.nav-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    text-decoration: none;
    transition: all var(--transition-fast);
    min-height: 40px;
    border: none;
    cursor: pointer
}

.nav-btn.primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-sm)
}

.nav-btn.primary:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md)
}

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

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

.hero {
    background: var(--gradient-primary);
    color: white;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    overflow: hidden
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="75" cy="75" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="50" cy="10" r="0.5" fill="rgba(255,255,255,0.05)"/><circle cx="20" cy="80" r="0.5" fill="rgba(255,255,255,0.05)"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
    pointer-events: none
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 900px;
    margin: 0 auto;
    padding: 0 var(--spacing-xl)
}

.hero-title {
    font-size: var(--font-size-5xl);
    font-weight: var(--font-weight-bold);
    line-height: var(--line-height-tight);
    margin-bottom: var(--spacing-xl);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    color: white !important
}

.hero-subtitle {
    font-size: var(--font-size-xl);
    line-height: var(--line-height-relaxed);
    margin-bottom: var(--spacing-3xl);
    opacity: 0.95;
    font-weight: var(--font-weight-normal)
}

.feature-highlights {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-4xl)
}

.highlight-tag {
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--radius-full);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: white;
    transition: all var(--transition-fast);
    cursor: default
}

.highlight-tag:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px)
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap
}

.cta-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 18px 35px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
    min-width: 200px
}

.cta-btn.android {
    background: linear-gradient(135deg, #34d399, #10b981);
    color: white;
    position: relative;
    overflow: hidden
}

.cta-btn.android::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s ease, height 0.6s ease
}

.cta-btn.android:hover::before {
    width: 300px;
    height: 300px
}

.cta-btn.wechat {
    background: #25d366;
    color: white
}

.cta-btn:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.35);
    filter: brightness(1.1)
}

.cta-btn:active {
    transform: translateY(-1px) scale(0.98);
    transition: all 0.1s ease
}

.cta-btn:focus {
    outline: none;
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.35), 0 0 0 3px rgba(102, 126, 234, 0.4)
}

.cta-btn .icon {
    font-size: 1.3rem
}

.cta-btn .text {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center
}

.cta-btn .text strong {
    font-size: 1.1rem
}

.cta-btn .text small {
    font-size: 0.85rem;
    opacity: 0.8
}

.section {
    padding: var(--spacing-5xl) 0
}

.illustration-section {
    background: var(--background-white);
    padding: var(--spacing-3xl) 0 var(--spacing-2xl) 0
}

.features-section {
    padding: var(--spacing-2xl) 0 var(--spacing-5xl) 0
}

.image-container {
    margin: 0 auto;
    text-align: center;
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center
}

.responsive-image {
    width: 100%;
    max-width: 800px;
    height: auto;
    aspect-ratio: 4/3;
    border-radius: 15px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
    transition: transform 0.3s ease;
    display: block;
    margin: 0 auto
}

.responsive-image:hover {
    transform: scale(1.02)
}

.features-section {
    background: var(--background-white)
}

.features-section h2 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-4xl);
    font-size: var(--font-size-3xl)
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-2xl)
}

.feature-card {
    background: var(--background-white);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: transform var(--transition-normal);
    transform-origin: left
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl)
}

.feature-card:hover::before {
    transform: scaleX(1)
}

.feature-icon {
    font-size: var(--font-size-4xl);
    margin-bottom: var(--spacing-lg);
    display: block
}

.feature-card h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    font-size: var(--font-size-xl)
}

.feature-card p {
    color: var(--text-secondary);
    line-height: var(--line-height-loose);
    margin: 0
}

.feature-image-section {
    background: var(--background-primary);
    padding: var(--spacing-5xl) 0
}

.feature-image-container {
    max-width: 800px;
    margin: 0 auto;
    border-radius: var(--radius-2xl);
    overflow: hidden;
    box-shadow: var(--shadow-2xl);
    position: relative
}

.feature-image {
    width: 100%;
    height: auto;
    aspect-ratio: 4/3;
    object-fit: cover;
    transition: transform var(--transition-slow)
}

.feature-image:hover {
    transform: scale(1.02)
}

.feature-image.loading {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite
}

.feature-image.error {
    background: var(--background-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-light);
    font-size: var(--font-size-lg)
}

@keyframes loading {
    0% {
        background-position: 200% 0
    }

    100% {
        background-position: -200% 0
    }
}

.cefr-section {
    background: var(--background-white);
    padding: var(--spacing-6xl) 0
}

.cefr-section h2 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-2xl);
    font-size: var(--font-size-3xl)
}

.level-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl)
}

.level-card {
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    color: white;
    text-align: center;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-lg)
}

.level-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: inherit;
    opacity: 0.9;
    z-index: 1
}

.level-card>* {
    position: relative;
    z-index: 2
}

.level-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-2xl)
}

.level-card h3 {
    font-size: var(--font-size-3xl);
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-sm);
    color: white
}

.level-card p {
    font-size: var(--font-size-sm);
    line-height: var(--line-height-relaxed);
    margin: 0;
    opacity: 0.9
}

.level-a1 {
    background: linear-gradient(135deg, #4CAF50, #45a049)
}

.level-a2 {
    background: linear-gradient(135deg, #8BC34A, #7CB342)
}

.level-b1 {
    background: linear-gradient(135deg, #FF9800, #F57C00)
}

.level-b2 {
    background: linear-gradient(135deg, #FF5722, #E64A19)
}

.level-c1 {
    background: linear-gradient(135deg, #9C27B0, #7B1FA2)
}

.level-c2 {
    background: linear-gradient(135deg, #673AB7, #512DA8)
}

.footer {
    background: var(--text-primary);
    color: white;
    padding: var(--spacing-4xl) 0
}

.footer-content {
    text-align: center
}

.footer-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg)
}

.footer-logo img {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm)
}

.footer-brand-name {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold)
}

.footer-description {
    font-size: var(--font-size-lg);
    line-height: var(--line-height-relaxed);
    margin-bottom: var(--spacing-xl);
    opacity: 0.9;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto
}

.footer-keywords {
    font-size: var(--font-size-sm);
    line-height: var(--line-height-relaxed);
    margin-bottom: var(--spacing-xl);
    opacity: 0.8
}

.footer-keywords span {
    display: inline-block;
    margin: 0 var(--spacing-xs)
}

.footer-copyright {
    font-size: var(--font-size-sm);
    opacity: 0.7
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0
}

/* Mobile Responsive Styles */
@media (max-width: 639px) {
    .hero-title {
        font-size: 1.75rem !important;
        line-height: 1.3;
        letter-spacing: -0.01em;
    }

    .hero-subtitle {
        font-size: var(--font-size-lg);
        line-height: 1.5;
    }

    .hero-content {
        padding: 0 var(--spacing-md);
    }

    .feature-highlights {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-md);
    }

    .highlight-tag {
        width: 100%;
        max-width: 300px;
        text-align: center;
        min-height: 44px;
        display: flex;
        align-items: center;
        justify-content: center;
    }

    .cta-buttons {
        flex-direction: column;
        gap: var(--spacing-lg);
    }

    .cta-btn {
        width: 100%;
        max-width: 320px;
        padding: var(--spacing-lg) var(--spacing-xl);
    }
}