/* ===== CSS Variables ===== */
:root {
    --primary-color: #1a1a1a;
    --secondary-color: #2d2d2d;
    --accent-color: #0066cc;
    --background-color: #ffffff;
    --background-alt: #fafafa;
    --border-color: #e0e0e0;
    --text-color: #1a1a1a;
    --text-light: #666666;
    --max-width: 1200px;
    --section-padding: 80px 0;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: var(--section-padding);
}

.section__title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--primary-color);
}

/* ===== Header & Navigation ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    z-index: 1000;
    transition: var(--transition);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav__logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

.nav__logo:hover {
    color: var(--accent-color);
}

.nav__menu {
    display: flex;
}

.nav__list {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav__link {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent-color);
    transition: var(--transition);
}

.nav__link:hover::after,
.nav__link.active::after {
    width: 100%;
}

.nav__link:hover,
.nav__link.active {
    color: var(--accent-color);
}

.nav__toggle,
.nav__close {
    display: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--primary-color);
}

/* ===== Hero Section ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--background-alt) 0%, var(--background-color) 100%);
    padding-top: 70px;
}

.hero__container {
    text-align: center;
}

.hero__title {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--primary-color);
    animation: fadeInUp 0.8s ease;
}

.hero__subtitle {
    font-size: 1.5rem;
    color: var(--accent-color);
    margin-bottom: 1rem;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero__description {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    animation: fadeInUp 0.8s ease 0.4s both;
}

/* ===== Buttons ===== */
.button {
    display: inline-block;
    padding: 12px 30px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: 500;
    transition: var(--transition);
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.button--primary {
    background-color: var(--accent-color);
    color: white;
    animation: fadeInUp 0.8s ease 0.6s both;
}

.button--primary:hover {
    background-color: #0052a3;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 102, 204, 0.3);
}

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

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

.about__text {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-light);
    text-align: center;
}

/* ===== Technology Section ===== */
.technology {
    background-color: var(--background-alt);
}

.technology__content {
    display: grid;
    gap: 3rem;
}

.technology__category {
    margin-bottom: 2rem;
}

.technology__category-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.technology__grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 1.5rem;
}

.technology__item {
    background-color: var(--background-color);
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.6s ease forwards;
}

.technology__item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    border-color: var(--accent-color);
}

.technology__item-name {
    font-weight: 600;
    color: var(--primary-color);
    margin-top: 0.5rem;
}

/* ===== Books Section ===== */
.books {
    background-color: var(--background-color);
}

.books__content {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
}

.book-card {
    background-color: var(--background-alt);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.6s ease forwards;
}

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

.book-card__cover {
    width: 100%;
    height: 400px;
    object-fit: cover;
    background-color: var(--border-color);
}

.book-card__content {
    padding: 1.5rem;
}

.book-card__title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.book-card__author {
    color: var(--text-light);
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
}

.book-card__rating {
    color: #ffa500;
    margin-bottom: 0.75rem;
    font-size: 1.1rem;
}

.book-card__review {
    color: var(--text-light);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: 0.5rem;
}

.book-card__date {
    color: var(--text-light);
    font-size: 0.85rem;
    font-style: italic;
}

/* ===== Travel Section ===== */
.travel {
    background-color: var(--background-alt);
}

.travel__content {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 2rem;
}

.travel-card {
    background-color: var(--background-color);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.6s ease forwards;
}

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

.travel-card__image {
    width: 100%;
    height: 250px;
    object-fit: cover;
    background-color: var(--border-color);
}

.travel-card__content {
    padding: 1.5rem;
}

.travel-card__location {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.travel-card__date {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.travel-card__description {
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.travel-card__highlights {
    list-style: none;
    padding: 0;
}

.travel-card__highlights li {
    color: var(--text-light);
    font-size: 0.9rem;
    padding: 0.25rem 0;
    padding-left: 1.5rem;
    position: relative;
}

.travel-card__highlights li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--accent-color);
}

/* ===== Contact Section ===== */
.contact {
    background-color: var(--background-color);
}

.contact__content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.contact__text {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.contact__links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.contact__link {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
    padding: 0.75rem 1.5rem;
    border: 2px solid var(--accent-color);
    border-radius: 5px;
    transition: var(--transition);
}

.contact__link:hover {
    background-color: var(--accent-color);
    color: white;
    transform: translateY(-2px);
}

/* ===== Footer ===== */
.footer {
    background-color: var(--background-alt);
    padding: 2rem 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

.footer__text {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* ===== Animations ===== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Responsive Design ===== */
@media screen and (max-width: 768px) {
    .nav__menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background-color: var(--background-color);
        padding: 4rem 2rem;
        box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
        transition: var(--transition);
    }

    .nav__menu.show-menu {
        right: 0;
    }

    .nav__list {
        flex-direction: column;
        gap: 1.5rem;
    }

    .nav__toggle,
    .nav__close {
        display: block;
    }

    .nav__close {
        position: absolute;
        top: 1.5rem;
        right: 1.5rem;
    }

    .hero__title {
        font-size: 2.5rem;
    }

    .hero__subtitle {
        font-size: 1.2rem;
    }

    .section__title {
        font-size: 2rem;
    }

    .technology__grid {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
        gap: 1rem;
    }

    .books__content,
    .travel__content {
        grid-template-columns: 1fr;
    }

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

@media screen and (max-width: 480px) {
    .hero__title {
        font-size: 2rem;
    }

    .section__title {
        font-size: 1.75rem;
    }

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