:root {
    --primary: #6366f1;
    --secondary: #8b5cf6;
    --dark: #0f172a;
    --text: #334155;
    --bg: #f1f5f9;
    --white: #ffffff;
    --shadow: 0 10px 30px rgba(0, 0, 0, .08);
}

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

body {
    font-family: 'Poppins', sans-serif;
    background: var(--bg);
    color: var(--text);
    overflow-x: hidden;
}

.navbar {
    position: sticky;
    top: 0;
    z-index: 1000;

    display: flex;
    justify-content: space-between;
    align-items: center;

    padding: 16px 6%;

    background: rgba(255, 255, 255, .7);
    backdrop-filter: blur(20px);

    border-bottom: 1px solid rgba(255, 255, 255, .4);
}

.logo {
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--primary);
}

.nav-links {
    display: flex;
    gap: 20px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    transition: .3s;
}

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

.hero {
    min-height: 90vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;

    text-align: center;

    padding: 80px 20px;

    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    color: white;

    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: rgba(255, 255, 255, .2);
    filter: blur(100px);
    top: -100px;
    left: -100px;
}

.hero h1 {
    font-size: clamp(2rem, 6vw, 4.5rem);
    line-height: 1.1;
    font-weight: 800;
}

.hero p {
    margin-top: 15px;
    max-width: 700px;
    font-size: clamp(.95rem, 2vw, 1.2rem);
    opacity: .95;
}

/* badge */
.badge {
    margin-top: 20px;
    padding: 8px 16px;
    border-radius: 50px;
    background: rgba(255, 255, 255, .2);
    backdrop-filter: blur(10px);
    font-size: .85rem;
}

.quotes {
    margin-top: 40px;
    width: 100%;
    max-width: 1200px;

    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
}

.quote {
    background: rgba(255, 255, 255, .15);
    backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, .2);

    padding: 18px;
    border-radius: 16px;

    transition: .3s;
}

.quote:hover {
    transform: translateY(-6px);
}

.section-title {
    text-align: center;
    margin: 60px 0 30px;
}

.section-title h2 {
    font-size: clamp(1.5rem, 4vw, 2.5rem);
    color: var(--dark);
}

.books {
    max-width: 1400px;
    margin: auto;
    padding: 0 5% 70px;

    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 25px;
}

.book {
    background: white;
    border-radius: 18px;
    overflow: hidden;
    box-shadow: var(--shadow);

    transition: .4s ease;
}

.book:hover {
    transform: translateY(-10px);
}

.book img {
    width: 100%;
    height: 280px;
    object-fit: cover;
}

.book-content {
    padding: 18px;
}

.book-content h3 {
    font-size: 1.1rem;
    margin-bottom: 6px;
}

.book-content p {
    font-size: .9rem;
    color: #64748b;
    margin-bottom: 15px;
}

/* button */
.download-btn {
    display: block;
    text-align: center;

    padding: 12px;
    border-radius: 30px;

    text-decoration: none;
    color: white;

    background: linear-gradient(135deg, var(--primary), var(--secondary));

    transition: .3s;
}

.download-btn:hover {
    transform: scale(1.03);
}

footer {
    background: var(--dark);
    color: white;
    padding: 60px 6%;
}

.footer-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 30px;
}

.footer-box h3 {
    margin-bottom: 10px;
}

.footer-box a {
    display: block;
    color: #cbd5e1;
    text-decoration: none;
    margin-bottom: 8px;
    font-size: .9rem;
    transition: .3s;
}

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

.footer-bottom {
    text-align: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, .1);
    color: #94a3b8;
}

@media(max-width:768px) {

    .navbar {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }

    .hero {
        min-height: 80vh;
        padding: 60px 15px;
    }

}

@media(max-width:480px) {

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

    .book img {
        height: 240px;
    }

}