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

:root {
    --color-bg: #ffffff;
    --color-text: #1a1a1a;
    --color-gray: #666666;
    --color-border: #e0e0e0;
    --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    --spacing-unit: 8px;
}

body {
    font-family: var(--font-primary);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    font-size: 16px;
    overflow-x: hidden;
}

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: calc(var(--spacing-unit) * 3) calc(var(--spacing-unit) * 4);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 14px;
    font-weight: 400;
    letter-spacing: 2px;
    color: var(--color-text);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: calc(var(--spacing-unit) * 5);
}

.nav-link {
    text-decoration: none;
    color: var(--color-gray);
    font-size: 13px;
    letter-spacing: 1.5px;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-text);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    right: 0;
    height: 1px;
    background-color: var(--color-text);
}

/* Main Content */
.main-content {
    margin-top: 73px;
}

/* Pages */
.page {
    display: none;
    min-height: calc(100vh - 73px);
    animation: fadeIn 0.5s ease;
}

.page.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Container */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: calc(var(--spacing-unit) * 10) calc(var(--spacing-unit) * 4);
}

.container-wide {
    max-width: 1400px;
    margin: 0 auto;
    padding: calc(var(--spacing-unit) * 10) calc(var(--spacing-unit) * 4);
}

/* Page Title */
.page-title {
    font-size: 12px;
    font-weight: 400;
    letter-spacing: 3px;
    color: var(--color-gray);
    margin-bottom: calc(var(--spacing-unit) * 8);
}

/* HOME Page */
.hero-image {
    width: 100%;
    height: calc(100vh - 73px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: calc(var(--spacing-unit) * 4);
}

.image-placeholder {
    width: 100%;
    max-width: 1200px;
    height: 70vh;
    background-color: #f5f5f5;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gray);
    font-size: 14px;
    letter-spacing: 2px;
}

/* ABOUT Page */
.about-content {
    max-width: 650px;
}

.about-content p {
    font-size: 18px;
    line-height: 1.8;
    color: var(--color-text);
    margin-bottom: calc(var(--spacing-unit) * 3);
}

/* WRITING Page */
.writing-list {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 6);
}

.writing-item {
    border-bottom: 1px solid var(--color-border);
    padding-bottom: calc(var(--spacing-unit) * 4);
    cursor: pointer;
    transition: opacity 0.3s ease;
}

.writing-item:hover {
    opacity: 0.7;
}

.writing-title {
    font-size: 24px;
    font-weight: 400;
    margin-bottom: calc(var(--spacing-unit) * 2);
    color: var(--color-text);
}

.writing-description {
    font-size: 15px;
    line-height: 1.7;
    color: var(--color-gray);
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.writing-date {
    font-size: 12px;
    letter-spacing: 1px;
    color: var(--color-gray);
}

/* WRITING Detail Page */
.back-button {
    background: none;
    border: none;
    color: var(--color-gray);
    font-size: 13px;
    letter-spacing: 1px;
    cursor: pointer;
    margin-bottom: calc(var(--spacing-unit) * 6);
    padding: calc(var(--spacing-unit) * 2) 0;
    transition: color 0.3s ease;
}

.back-button:hover {
    color: var(--color-text);
}

.writing-detail-content {
    max-width: 700px;
}

.detail-title {
    font-size: 32px;
    font-weight: 400;
    margin-bottom: calc(var(--spacing-unit) * 2);
    line-height: 1.4;
}

.detail-date,
.detail-year {
    font-size: 12px;
    letter-spacing: 1px;
    color: var(--color-gray);
    display: block;
    margin-bottom: calc(var(--spacing-unit) * 6);
}

.detail-body {
    font-size: 16px;
    line-height: 1.9;
    color: var(--color-text);
}

.detail-body p {
    margin-bottom: calc(var(--spacing-unit) * 3);
}

/* WORKS Page */
.works-grid {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 10);
}

.work-item {
    cursor: pointer;
    transition: opacity 0.3s ease;
}

.work-item:hover {
    opacity: 0.8;
}

.work-image-container {
    width: 100%;
    margin-bottom: calc(var(--spacing-unit) * 3);
    position: relative;
    overflow: hidden;
}

.work-image {
    width: 100%;
    height: 400px;
    object-fit: cover;
    display: block;
}

.work-image-placeholder {
    width: 100%;
    height: 400px;
    background-color: #f5f5f5;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gray);
    font-size: 14px;
    letter-spacing: 2px;
}

.work-title {
    font-size: 20px;
    font-weight: 400;
    letter-spacing: 1px;
    margin-bottom: calc(var(--spacing-unit));
}

.work-year {
    font-size: 13px;
    color: var(--color-gray);
    letter-spacing: 1px;
}

/* WORK Detail Page */
.work-detail-content {
    max-width: 1000px;
}

.detail-images {
    margin-bottom: calc(var(--spacing-unit) * 6);
}

.detail-image {
    width: 100%;
    height: auto;
    display: block;
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.detail-image-placeholder {
    width: 100%;
    height: 500px;
    background-color: #f5f5f5;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gray);
    font-size: 14px;
    letter-spacing: 2px;
    margin-bottom: calc(var(--spacing-unit) * 3);
}

/* CONTACT Page */
.contact-content {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 6);
    max-width: 500px;
}

.contact-info {
    border-bottom: 1px solid var(--color-border);
    padding-bottom: calc(var(--spacing-unit) * 3);
}

.contact-label {
    font-size: 11px;
    letter-spacing: 2px;
    color: var(--color-gray);
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.contact-value {
    font-size: 18px;
    color: var(--color-text);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        gap: calc(var(--spacing-unit) * 3);
        padding: calc(var(--spacing-unit) * 2);
    }

    .nav-menu {
        gap: calc(var(--spacing-unit) * 3);
        flex-wrap: wrap;
        justify-content: center;
    }

    .main-content {
        margin-top: 110px;
    }

    .page {
        min-height: calc(100vh - 110px);
    }

    .hero-image {
        height: calc(100vh - 110px);
    }

    .container,
    .container-wide {
        padding: calc(var(--spacing-unit) * 6) calc(var(--spacing-unit) * 3);
    }

    .writing-title {
        font-size: 20px;
    }

    .detail-title {
        font-size: 26px;
    }

    .work-image-placeholder {
        height: 250px;
    }
    
    .work-image {
        height: 250px;
    }

    .detail-image-placeholder {
        height: 300px;
    }
}

@media (max-width: 480px) {
    .logo {
        font-size: 12px;
    }

    .nav-link {
        font-size: 11px;
    }

    .writing-title {
        font-size: 18px;
    }

    .detail-title {
        font-size: 22px;
    }

    .contact-value {
        font-size: 16px;
    }
}