/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: #1a202c;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

/* Header */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 2rem;
    text-align: center;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    position: relative;
}

.header-content {
    max-width: 800px;
    margin: 0 auto;
}

.main-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #2d3748;
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.2rem;
    color: #4a5568;
    margin-bottom: 0.5rem;
}

.credits {
    font-size: 0.9rem;
    color: #718096;
    margin-bottom: 1rem;
}

.credits a {
    color: #4299e1;
    text-decoration: none;
    border-bottom: 1px solid rgba(66, 153, 225, 0.3);
    transition: all 0.2s ease;
}

.credits a:hover {
    color: #3182ce;
    border-bottom-color: #3182ce;
}

.language-toggle {
    position: absolute;
    top: 2rem;
    right: 2rem;
    background: #4299e1;
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.language-toggle:hover {
    background: #3182ce;
    transform: translateY(-1px);
}

.language-toggle:focus {
    outline: 2px solid #63b3ed;
    outline-offset: 2px;
}

/* Main Content */
.main-content {
    padding: 3rem 2rem;
    max-width: 1400px;
    margin: 0 auto;
}

.apps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
}

/* App Cards */
.app-card {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    border-left: 4px solid transparent;
    position: relative;
    overflow: hidden;
}

.app-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.app-card.research {
    border-left-color: #9f7aea;
}

.app-card.finance {
    border-left-color: #48bb78;
}

.app-card.game {
    border-left-color: #ed8936;
}

.app-card.education {
    border-left-color: #4299e1;
}

.app-header {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.app-icon {
    font-size: 2.5rem;
    flex-shrink: 0;
}

.app-info {
    flex: 1;
}

.app-title {
    font-size: 1.4rem;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 0.25rem;
    line-height: 1.3;
}

.app-subtitle {
    font-size: 0.9rem;
    color: #718096;
    font-style: italic;
    margin-bottom: 0.5rem;
}

.app-date {
    font-size: 0.8rem;
    color: #a0aec0;
    background: #f7fafc;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    display: inline-block;
}

.app-description {
    margin-bottom: 1.5rem;
}

.app-desc {
    color: #4a5568;
    margin-bottom: 1rem;
    font-weight: 500;
}

.feature-list {
    list-style: none;
    margin: 0;
    padding: 0;
}

.feature-list li {
    padding: 0.5rem 0;
    color: #4a5568;
    font-size: 0.9rem;
    line-height: 1.4;
    border-bottom: 1px solid #e2e8f0;
}

.feature-list li:last-child {
    border-bottom: none;
}

.app-link {
    display: inline-block;
    background: linear-gradient(135deg, #4299e1, #3182ce);
    color: white;
    text-decoration: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 500;
    transition: all 0.2s ease;
    box-shadow: 0 4px 15px rgba(66, 153, 225, 0.3);
}

.app-link:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(66, 153, 225, 0.4);
}

/* Footer */
.footer {
    text-align: center;
    padding: 2rem;
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
}

.footer a {
    color: white;
    text-decoration: none;
    border-bottom: 1px solid rgba(255, 255, 255, 0.3);
    transition: all 0.2s ease;
}

.footer a:hover {
    color: white;
    border-bottom-color: white;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header {
        padding: 1.5rem 1rem;
    }

    .language-toggle {
        position: static;
        margin-top: 1rem;
    }

    .main-title {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .main-content {
        padding: 2rem 1rem;
    }

    .apps-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .app-card {
        padding: 1.5rem;
    }

    .app-header {
        flex-direction: column;
        text-align: center;
        gap: 0.5rem;
    }

    .app-icon {
        font-size: 2rem;
    }

    .app-title {
        font-size: 1.2rem;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 1rem;
    }

    .main-title {
        font-size: 1.8rem;
    }

    .app-card {
        padding: 1rem;
    }

    .feature-list li {
        font-size: 0.85rem;
        padding: 0.4rem 0;
    }

    .app-link {
        width: 100%;
        text-align: center;
        padding: 1rem;
    }
}