:root {
    /* Ana Renkler */
    --color-primary: #5EADB5;
    --color-primary-dark: #4d9ca4;
    --color-primary-light: #6bb8c0;
    
    /* Nötr Renkler */
    --color-dark: #111213;
    --color-dark-secondary: #1d1d1f;
    --color-light: #ffffff;
    --color-gray: rgba(17, 18, 19, 0.7);
    --color-gray-light: rgba(17, 18, 19, 0.6);
    
    /* Tipografi */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --line-height: 1.6;
    
    /* Spacing */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 40px;
    --spacing-xl: 60px;
    --spacing-2xl: 80px;
    --spacing-3xl: 120px;
    
    /* Border Radius */
    --radius-sm: 12px;
    --radius-md: 20px;
    --radius-lg: 24px;
    --radius-full: 50px;
    
    /* Transitions */
    --transition-fast: 0.3s ease;
    --transition-medium: 0.5s ease;
    
    /* Shadows */
    --shadow-light: 0 10px 30px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 20px 60px rgba(0, 0, 0, 0.08);
    --shadow-heavy: 0 10px 30px rgba(0, 0, 0, 0.3);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    color: var(--color-dark-secondary);
    line-height: var(--line-height);
    background: var(--color-light);
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ============================================
   Navigation
   ============================================ */
.nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    z-index: 1000;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.nav__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 15px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav__logo {
    font-size: 20px;
    font-weight: 600;
    color: var(--color-primary);
}

.nav__links {
    display: flex;
    gap: var(--spacing-lg);
}

.nav__link {
    color: var(--color-dark-secondary);
    font-size: 14px;
    transition: opacity var(--transition-fast);
}

.nav__link:hover {
    opacity: 0.6;
}

/* Mobile Menu Toggle */
.nav__toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 5px;
}

.nav__toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-dark);
    transition: var(--transition-fast);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    position: relative;
    margin-top: 60px;
    min-height: 100vh;
    display: flex;
    align-items: center;
    overflow: hidden;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
}

.hero__shapes {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.hero__shape {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    animation: float-shape 20s ease-in-out infinite;
}

.hero__shape--1 {
    width: 300px;
    height: 300px;
    top: 10%;
    right: 15%;
    animation-delay: 0s;
}

.hero__shape--2 {
    width: 200px;
    height: 200px;
    bottom: 15%;
    left: 10%;
    animation-delay: 2s;
}

.hero__shape--3 {
    width: 150px;
    height: 150px;
    top: 60%;
    right: 25%;
    animation-delay: 4s;
}

@keyframes float-shape {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -30px) scale(1.1); }
    66% { transform: translate(-20px, 20px) scale(0.9); }
}

.hero__content {
    position: relative;
    z-index: 10;
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-3xl) 30px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
}

.hero__text {
    color: var(--color-light);
}

.hero__badge {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-full);
    font-size: 14px;
    font-weight: 500;
    margin-bottom: var(--spacing-md);
}

.hero__title {
    font-size: 72px;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    line-height: 1.1;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

.hero__authors {
    font-size: 24px;
    margin-bottom: 32px;
    opacity: 0.95;
}

.hero__description {
    font-size: 20px;
    line-height: 1.7;
    margin-bottom: var(--spacing-lg);
    opacity: 0.9;
}

.hero__buttons {
    display: flex;
    gap: var(--spacing-sm);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    padding: var(--spacing-sm) 32px;
    border-radius: var(--radius-sm);
    font-size: 16px;
    font-weight: 500;
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
}

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

.btn--primary:hover {
    background: rgba(17, 18, 19, 0.9);
    transform: translateY(-2px);
    box-shadow: var(--shadow-heavy);
}

.btn--secondary {
    background: rgba(255, 255, 255, 0.2);
    color: var(--color-light);
    border: 2px solid var(--color-light);
}

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

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

.btn--white:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-light);
}

/* ============================================
   Book 3D Component
   ============================================ */
.hero__book {
    position: relative;
    perspective: 1000px;
}

.book-3d {
    position: relative;
    width: 100%;
    max-width: 400px;
    margin: 0 auto;
    transform: rotateY(-15deg);
    transition: transform var(--transition-medium);
}

.hero__book:hover .book-3d {
    transform: rotateY(0deg) scale(1.05);
}

.book-3d__cover {
    background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-primary) 50%, var(--color-primary-dark) 100%);
    border-radius: var(--radius-md);
    padding: var(--spacing-xl) var(--spacing-lg);
    text-align: center;
    box-shadow: 
        20px 20px 60px rgba(0, 0, 0, 0.3),
        -5px 0 20px rgba(0, 0, 0, 0.1);
    position: relative;
}

.book-3d__cover::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 30px;
    background: linear-gradient(90deg, rgba(0, 0, 0, 0.2) 0%, transparent 100%);
    border-radius: var(--radius-md) 0 0 var(--radius-md);
}

.book-3d__icon {
    font-size: 120px;
    margin-bottom: 30px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.book-3d__title {
    font-size: 42px;
    font-weight: 700;
    color: var(--color-light);
    margin-bottom: var(--spacing-md);
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.book-3d__authors {
    font-size: 18px;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 500;
}

/* ============================================
   Section Common Styles
   ============================================ */
.section {
    padding: var(--spacing-3xl) 30px;
}

.section__container {
    max-width: 1200px;
    margin: 0 auto;
}

.section__label {
    display: inline-block;
    color: var(--color-primary);
    font-size: 14px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: var(--spacing-sm);
}

.section__title {
    font-size: 48px;
    font-weight: 700;
    color: var(--color-dark);
    margin-bottom: 32px;
}

.section__title--light {
    color: var(--color-light);
}

/* ============================================
   About Section
   ============================================ */
.about {
    background: var(--color-light);
}

.about__content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    margin-top: var(--spacing-xl);
}

.about__text p {
    font-size: 18px;
    color: var(--color-gray);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.about__text strong {
    color: var(--color-dark);
}

.about__text em {
    color: var(--color-dark);
    font-style: italic;
}

/* Stats */
.stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.stats__item {
    text-align: center;
}

.stats__number {
    font-size: 48px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.stats__label {
    font-size: 16px;
    color: var(--color-gray-light);
}

/* ============================================
   Authors Section
   ============================================ */
.authors {
    background: linear-gradient(to bottom, var(--color-light), rgba(245, 243, 239, 0.3));
}

.authors__grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.author-card {
    background: var(--color-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    border: 1px solid rgba(232, 228, 222, 0.5);
    transition: all var(--transition-fast);
}

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

.author-card__avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 36px;
    color: var(--color-light);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.author-card__name {
    font-size: 28px;
    font-weight: 600;
    color: var(--color-dark);
    margin-bottom: var(--spacing-xs);
}

.author-card__title {
    font-size: 16px;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.author-card__bio {
    font-size: 16px;
    color: var(--color-gray);
    line-height: 1.7;
}

/* ============================================
   Oksipital Section
   ============================================ */
.oksipital {
    background: linear-gradient(135deg, var(--color-dark) 0%, var(--color-dark-secondary) 100%);
    color: var(--color-light);
}

.oksipital .section__label {
    color: var(--color-primary);
}

.oksipital__intro {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--spacing-xl);
    font-size: 20px;
    color: rgba(255, 255, 255, 0.8);
}

.oksipital__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.oksipital-feature {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    padding: 32px;
    transition: all var(--transition-fast);
}

.oksipital-feature:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--color-primary);
    transform: translateY(-8px);
}

.oksipital-feature__icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.oksipital-feature__title {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-light);
}

.oksipital-feature__desc {
    font-size: 16px;
    line-height: 1.7;
    color: rgba(255, 255, 255, 0.7);
}

.oksipital__cta {
    text-align: center;
    margin-top: var(--spacing-xl);
}

/* ============================================
   Features Section
   ============================================ */
.features {
    background: var(--color-dark);
    color: var(--color-light);
}

.features .section__label {
    color: var(--color-primary);
}

.features__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.feature-card {
    text-align: center;
}

.feature-card__icon {
    font-size: 48px;
    margin-bottom: var(--spacing-md);
}

.feature-card__title {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.feature-card__desc {
    font-size: 16px;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.7;
}

/* ============================================
   CTA Section
   ============================================ */
.cta {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    text-align: center;
    color: var(--color-light);
}

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

.cta__title {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.cta__text {
    font-size: 20px;
    margin-bottom: var(--spacing-lg);
    opacity: 0.9;
}

.cta__buttons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background: var(--color-dark);
    color: var(--color-light);
    padding: var(--spacing-xl) 30px;
    text-align: center;
}

.footer__logo {
    font-size: 24px;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.footer__tagline {
    color: rgba(255, 255, 255, 0.6);
    margin-bottom: var(--spacing-md);
}

.footer__copyright {
    color: rgba(255, 255, 255, 0.6);
    font-size: 14px;
}

/* ============================================
   Responsive Design
   ============================================ */

/* Tablet */
@media (max-width: 1024px) {
    .hero__content {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }

    .hero__text {
        text-align: center;
    }

    .hero__buttons {
        justify-content: center;
    }

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

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

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

    .oksipital__grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Mobile */
@media (max-width: 768px) {
    .nav__links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-light);
        flex-direction: column;
        padding: var(--spacing-md);
        gap: var(--spacing-sm);
        border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    }

    .nav__links.active {
        display: flex;
    }

    .nav__toggle {
        display: flex;
    }

    .hero__title {
        font-size: 48px;
    }

    .section__title {
        font-size: 36px;
    }

    .hero__buttons {
        flex-direction: column;
        align-items: center;
    }

    .cta__buttons {
        flex-direction: column;
        align-items: center;
    }

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

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

    .book-3d__title {
        font-size: 32px;
    }

    .book-3d__icon {
        font-size: 80px;
    }

    .cta__title {
        font-size: 36px;
    }
}

/* Small Mobile */
@media (max-width: 480px) {
    .hero__title {
        font-size: 36px;
    }

    .section__title {
        font-size: 28px;
    }

    .hero__description {
        font-size: 16px;
    }

    .author-card__name {
        font-size: 22px;
    }

    .stats__number {
        font-size: 36px;
    }
}

/* ============================================
   Utility Classes
   ============================================ */
.text-center {
    text-align: center;
}

.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;
}