:root {
    --primary-color: #4a90e2;
    --secondary-color: #f5f7fa;
    --text-color: #333333;
    --light-text-color: #ffffff;
    --dark-bg-color: #2c3e50;
    --transition-duration: 0.3s;
}

body {
    font-family: 'Poppins', sans-serif;
    color: var(--text-color);
    background-color: var(--secondary-color);
}

.navbar {
    background-color: rgba(255, 255, 255, 0.95);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s ease;
}

.navbar-scrolled {
    background-color: #ffffff;
}

.navbar-brand {
    font-weight: 700;
    color: var(--primary-color);
}

.nav-link {
    font-weight: 500;
    color: var(--text-color);
    transition: color 0.3s ease;
}

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

.hero {
    background-color: var(--secondary-color);
    padding: 100px 0;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
}

.card {
    border: none;
    border-radius: 15px;
    overflow: hidden;
    transition: transform var(--transition-duration) ease, box-shadow var(--transition-duration) ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.password-display,
.username-display {
    display: flex;
    align-items: center;
}

.password-display input,
.username-display input {
    flex-grow: 1;
    font-size: 1.2rem;
    padding: 0.75rem;
    border: 2px solid #ced4da;
    border-radius: 5px;
}

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

.btn-primary:hover {
    background-color: #3a7bd5;
    border-color: #3a7bd5;
}

.strength-meter {
    margin-top: 1rem;
}

.progress {
    height: 10px;
    border-radius: 5px;
    overflow: hidden;
}

#strengthText {
    font-size: 0.9rem;
    font-weight: 500;
}

.feature-card {
    text-align: center;
    padding: 2rem;
    border-radius: 10px;
    background-color: #ffffff;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.feature-card i {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

#about {
    background-color: #ffffff;
}

footer {
    background-color: var(--dark-bg-color);
    color: var(--light-text-color);
}

footer a {
    color: var(--light-text-color);
    text-decoration: none;
}

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

@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }
}