:root {
    --color-primary: #0EA5E9;
    --color-primary-dark: #0284C7;
    --color-secondary: #F0F9FF;
    --color-text: #1E293B;
    --color-text-light: #64748B;
    --color-white: #FFFFFF;
}

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

body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    color: var(--color-text);
    background: linear-gradient(to bottom, var(--color-secondary), var(--color-white));
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background-color: var(--color-primary);
    color: var(--color-white);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo h1 {
    font-size: 1.5rem;
}

nav ul {
    display: flex;
    gap: 1.5rem;
    list-style: none;
}

nav a {
    color: var(--color-white);
    text-decoration: none;
}

main {
    padding: 2rem 0;
}

.hero {
    text-align: center;
    margin-bottom: 4rem;
}

.hero h2 {
    font-size: 2.5rem;
    color: var(--color-primary-dark);
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    color: var(--color-text-light);
    margin-bottom: 2rem;
}

.badges {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.badge {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background-color: var(--color-secondary);
    border-radius: 20px;
    font-size: 0.9rem;
}

.featured-notes, .how-it-works, .testimonials, .popular-subjects {
    margin-bottom: 4rem;
}

h3 {
    font-size: 2rem;
    color: var(--color-primary-dark);
    margin-bottom: 2rem;
    text-align: center;
}

.notes-grid, .steps-grid, .testimonials-grid, .subjects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.note-card, .step-card, .testimonial-card {
    background-color: var(--color-white);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.note-card:hover, .step-card:hover, .testimonial-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.note-icon {
    background-color: var(--color-secondary);
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 auto 1rem;
}

.note-icon i, .step-card i {
    font-size: 2rem;
    color: var(--color-primary);
}

.note-content h4, .step-card h4 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.note-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 1rem 0;
}

.rating {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

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

button {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.full-width {
    width: 100%;
}

.how-it-works {
    background-color: var(--color-secondary);
    padding: 3rem 0;
    border-radius: 8px;
}

.step-card {
    text-align: center;
    background-color: var(--color-white);
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.avatar {
    width: 50px;
    height: 50px;
    background-color: var(--color-primary);
    color: var(--color-white);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
}

.stars {
    color: #FFD700;
}

.quote {
    font-style: italic;
}

.cta {
    background-color: var(--color-primary);
    color: var(--color-white);
    text-align: center;
    padding: 3rem 0;
    border-radius: 8px;
    margin-bottom: 4rem;
}

.cta h3 {
    color: var(--color-white);
}

.cta button {
    background-color: var(--color-white);
    color: var(--color-primary);
    font-weight: bold;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    margin-top: 1rem;
}

.subject-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background-color: var(--color-white);
    color: var(--color-primary);
    border: 1px solid var(--color-primary);
    padding: 0.75rem 1rem;
    font-size: 1rem;
    transition: background-color 0.3s, color 0.3s;
}

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

footer {
    background-color: var(--color-primary-dark);
    color: var(--color-white);
    padding:  3rem 0 1rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.footer-section h4 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section a {
    color: var(--color-white);
    text-decoration: none;
}

.footer-bottom {
    margin-top: 2rem;
    text-align: center;
    padding-top: 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

@media (max-width: 768px) {
    .hero h2 {
        font-size: 2rem;
    }

    .notes-grid, .steps-grid, .testimonials-grid {
        grid-template-columns: 1fr;
    }

    .badges {
        flex-direction: column;
    }
}