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

/* gray-beige monochrome */
:root {
    --color-lightest: #f5f1ed;
    --color-light: #e8e2dc;
    --color-medium-light: #d4ccc4;
    --color-medium: #b8afa7;
    --color-medium-dark: #8b8179;
    --color-dark: #5d564f;
    --color-darkest: #3a342f;
    --color-accent: #9d8b7e;
    
    --font-primary: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-secondary: Georgia, 'Times New Roman', serif;
    
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2.5rem;
    --spacing-xl: 4rem;
    
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;

    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    line-height: 1.7;
    color: var(--color-darkest);
    background: linear-gradient(135deg, var(--color-lightest) 0%, var(--color-light) 100%);
    min-height: 100vh;
    overflow-x: hidden;
    padding-top: 80px;
}

/* typo */
h1, h2, h3, h4 {
    font-family: var(--font-secondary);
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-darkest);
    margin-bottom: var(--spacing-xs);
}

h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    letter-spacing: -0.02em;
}

h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    color: var(--color-dark);
    position: relative;
    padding-bottom: var(--spacing-sm);
    text-align: center;
    margin-bottom: var(--spacing-md);
}

h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--color-accent), transparent);
    border-radius: var(--radius-sm);
}

h3 {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    color: var(--color-medium-dark);
    font-weight: 600;
}

p {
    font-size: clamp(1rem, 2vw, 1.125rem);
    color: var(--color-dark);
    margin-bottom: var(--spacing-md);
    font-weight: 400;
}

strong {
    color: var(--color-darkest);
    font-weight: 600;
}

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

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: all var(--transition-normal);
    position: relative;
}

a:hover {
    color: var(--color-dark);
}

a:focus {
    outline: 2px solid var(--color-accent);
    outline-offset: 3px;
    border-radius: var(--radius-sm);
}

/* header & nav */
.site-header {
    background: rgba(245, 241, 237, 0.95);
    backdrop-filter: blur(10px);
    padding: var(--spacing-xs) var(--spacing-lg);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    box-shadow: 0 2px 20px rgba(58, 52, 47, 0.08);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    transition: transform var(--transition-normal);
}

.site-header.hidden {
    transform: translateY(-100%);
}

.logo {
    margin: 0;
}

.logo a {
    font-family: var(--font-secondary);
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    font-weight: 700;
    color: var(--color-darkest);
    letter-spacing: -0.01em;
    transition: color var(--transition-normal);
}

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

.site-nav ul {
    list-style: none;
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.site-nav a {
    color: var(--color-dark);
    font-weight: 500;
    font-size: clamp(0.9rem, 2vw, 1rem);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
    display: inline-block;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
    background: var(--color-light);
    color: var(--color-darkest);
    transform: translateY(-2px);
}

#main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg);
    flex: 1;
    width: 100%;
}

/* project section */
.project {
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl) var(--spacing-lg);
    box-shadow: 0 8px 40px rgba(58, 52, 47, 0.12);
}

.project > p {
    text-align: center;
    font-size: clamp(1.05rem, 2.5vw, 1.15rem);
    line-height: 1.8;
    max-width: 800px;
    margin: 0 auto var(--spacing-xl) auto;
    color: var(--color-dark);
}

/* internal nav */
aside {
    background: linear-gradient(135deg, rgba(232, 226, 220, 0.6), rgba(255, 255, 255, 0.8));
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    border: 2px solid var(--color-light);
    transition: all var(--transition-normal);
}

aside:hover {
    border-color: var(--color-accent);
    box-shadow: 0 4px 20px rgba(58, 52, 47, 0.1);
}

aside h3 {
    font-size: clamp(1.1rem, 2.5vw, 1.35rem);
    color: var(--color-darkest);
    margin-bottom: var(--spacing-sm);
    text-align: center;
}

aside nav ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-sm);
    padding: 0;
}

aside nav li {
    margin: 0;
}

aside nav a {
    display: block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: rgba(255, 255, 255, 0.7);
    border-radius: var(--radius-sm);
    font-size: clamp(0.9rem, 2vw, 1rem);
    font-weight: 500;
    color: var(--color-dark);
    transition: all var(--transition-normal);
    border-left: 3px solid transparent;
}

aside nav a:hover {
    background: var(--color-lightest);
    border-left-color: var(--color-accent);
    color: var(--color-darkest);
    transform: translateX(5px);
}

/* project-card */
.project-card {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.8), rgba(232, 226, 220, 0.4));
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: 0 6px 30px rgba(58, 52, 47, 0.1);
    transition: all var(--transition-normal);
    display: grid;
    gap: var(--spacing-lg);
    scroll-margin-top: 100px;
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 45px rgba(58, 52, 47, 0.18);
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.95), rgba(232, 226, 220, 0.5));
}

/* project image */
.project-card figure {
    margin: 0;
    position: relative;
    /* overflow: hidden; */
    /* border-radius: var(--radius-md); */
    background: var(--color-light);
}

.project-card img {
    width: 100%;
    height: auto;
    display: block;
    /* border-radius: var(--radius-md); */
    transition: transform var(--transition-slow), filter var(--transition-slow);
    filter: grayscale(1);
    object-fit: cover;
    max-height: 400px;
}

.project-card figure:hover img {
    transform: scale(1.05);
    filter: grayscale(0);
}

.project-card figcaption {
    text-align: center;
    font-size: clamp(0.85rem, 2vw, 0.95rem);
    color: var(--color-medium-dark);
    font-style: italic;
    margin-top: var(--spacing-sm);
    padding: var(--spacing-xs);
}

/* project-info */
.project-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.project-info h3 {
    color: var(--color-darkest);
    margin-bottom: var(--spacing-xs);
    position: relative;
    padding-bottom: var(--spacing-xs);
}

.project-info h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 2px;
    background: var(--color-accent);
    border-radius: var(--radius-sm);
}

.project-info p {
    font-size: clamp(1rem, 2vw, 1.1rem);
    line-height: 1.8;
    color: var(--color-dark);
    margin-bottom: var(--spacing-sm);
}

/* projecy-link */
.project-link {
    list-style: none;
    padding: 0;
    margin-top: var(--spacing-sm);
}

.project-link li {
    margin-bottom: var(--spacing-xs);
}

.project-link a {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--color-accent);
    color: var(--color-lightest);
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: clamp(0.9rem, 2vw, 1rem);
    transition: all var(--transition-normal);
    box-shadow: 0 2px 10px rgba(58, 52, 47, 0.15);
}

.project-link a:hover {
    background: var(--color-dark);
    color: var(--color-lightest);
    transform: translateX(5px);
    box-shadow: 0 4px 15px rgba(58, 52, 47, 0.25);
}

.project-link a:active {
    transform: translateX(3px);
}

/* back-to-top button */
.back-to-top {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    width: 50px;
    height: 50px;
    background: var(--color-accent);
    color: var(--color-lightest);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    box-shadow: 0 4px 20px rgba(58, 52, 47, 0.3);
    transition: all var(--transition-normal);
    z-index: 999;
}

.back-to-top:hover {
    color: var(--color-lightest);
    background: var(--color-dark);
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(58, 52, 47, 0.4);
}

/* footer */
.site-footer {
    background: linear-gradient(135deg, var(--color-dark), var(--color-darkest));
    color: var(--color-light);
    padding: var(--spacing-md);
    text-align: center;
    margin-top: var(--spacing-md);
}

.site-footer p {
    color: var(--color-light);
    margin-bottom: var(--spacing-md);
    font-size: clamp(0.9rem, 2vw, 1rem);
}

.site-footer strong {
    color: var(--color-medium);
}

.social-links {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.social-links a {
    display: inline-block;
    transition: transform var(--transition-normal);
}

.social-links a:hover {
    transform: scale(1.05) rotate(15deg);
}

.social-links img {
    width: clamp(20px, 5vw, 30px);
    height: clamp(20px, 5vw, 30px);
}

::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--color-lightest);
}

::-webkit-scrollbar-thumb {
    background: var(--color-medium);
    border-radius: 10px;
}

@media screen and (max-width: 768px) {
    :root {
        --spacing-lg: 2rem;
        --spacing-xl: 3rem;
    }
    
    body {
        padding-top: 160px;
    }
    
    .site-header {
        flex-direction: column;
        text-align: center;
        padding: var(--spacing-md);
        position: fixed;
    }
    
    .site-nav ul {
        justify-content: center;
        gap: var(--spacing-sm);
    }
    
    #main-content {
        padding: var(--spacing-lg) var(--spacing-md);
    }
    
    .project {
        padding: var(--spacing-lg) var(--spacing-md);
    }
    
    aside nav ul {
        grid-template-columns: 1fr;
    }
    
    .project-card {
        padding: var(--spacing-md);
    }
}

@media screen and (max-width: 480px) {
    :root {
        --spacing-md: 1rem;
        --spacing-lg: 1.5rem;
        --spacing-xl: 2rem;
    }
    
    body {
        padding-top: 130px;
    }
    
    .site-header {
        padding: var(--spacing-sm);
        position: fixed;
    }
    
    .site-nav ul {
        flex-direction: row;
        justify-content: center;
        gap: var(--spacing-xs);
        width: 100%;
        flex-wrap: wrap;
    }
    
    .site-nav a {
        font-size: clamp(0.75rem, 2vw, 0.85rem);
        padding: var(--spacing-xs) 0.6rem;
    }
    
    #main-content {
        padding: var(--spacing-md) var(--spacing-sm);
    }
    
    .project {
        padding: var(--spacing-md) var(--spacing-sm);
    }
    
    aside {
        padding: var(--spacing-sm);
    }
    
    aside nav ul {
        gap: var(--spacing-xs);
    }
    
    .project-card {
        padding: var(--spacing-sm);
        margin-bottom: var(--spacing-md);
        gap: var(--spacing-md);
    }
    
    .project-card img {
        max-height: 250px;
    }
    
    .back-to-top {
        bottom: var(--spacing-md);
        right: var(--spacing-md);
        width: 45px;
        height: 45px;
        font-size: 1.25rem;
    }
    
    .site-footer .social-links {
        gap: var(--spacing-sm);
    }
}

@media screen and (max-width: 320px) {
    :root {
        --spacing-xs: 0.35rem;
        --spacing-sm: 0.75rem;
        --spacing-md: 0.85rem;
        --spacing-lg: 1.25rem;
        --spacing-xl: 1.75rem;
    }
    
    body {
        padding-top: 140px;
    }
    
    .site-header {
        padding: var(--spacing-xs) var(--spacing-sm);
        position: fixed;
    }
    
    .logo a {
        font-size: clamp(1rem, 4vw, 1.25rem);
    }
    
    .site-nav ul {
        flex-direction: row;
        justify-content: center;
        gap: 0.25rem;
        flex-wrap: wrap;
    }
    
    .site-nav a {
        font-size: 0.7rem;
        padding: 0.3rem 0.5rem;
    }
    
    #main-content {
        padding: var(--spacing-md) var(--spacing-xs);
    }
    
    .project {
        padding: var(--spacing-md) var(--spacing-xs);
    }
    
    aside {
        padding: var(--spacing-xs);
    }
    
    aside h3 {
        font-size: 1rem;
    }
    
    aside nav ul {
        gap: 0.25rem;
    }
    
    aside nav a {
        font-size: 0.75rem;
        padding: 0.3rem 0.5rem;
    }
    
    .project-card {
        padding: var(--spacing-xs);
        gap: var(--spacing-sm);
    }
    
    .project-card img {
        max-height: 200px;
    }
    
    h2 {
        font-size: clamp(1.35rem, 5vw, 1.75rem);
    }
    
    h3 {
        font-size: clamp(1.1rem, 4vw, 1.35rem);
    }
    
    .project-link a {
        font-size: 0.8rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
    
    .back-to-top {
        bottom: var(--spacing-sm);
        right: var(--spacing-sm);
        width: 40px;
        height: 40px;
        font-size: 1.15rem;
    }
}

@media screen and (min-width: 1024px) {
    .project-card {
        grid-template-columns: 1fr 1fr;
        align-items: start;
    }
    
    .project-card:nth-child(even) figure {
        order: 2;
    }
    
    .project-card:nth-child(even) .project-info {
        order: 1;
    }
}

@media screen and (min-width: 1400px) {
    #main-content {
        max-width: 1300px;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

@media (prefers-contrast: high) {
    :root {
        --color-darkest: #000000;
        --color-lightest: #ffffff;
    }
    
    .project,
    .project-card,
    aside {
        border: 2px solid var(--color-darkest);
    }
}

@media print {
    .site-header,
    .back-to-top,
    aside,
    .site-footer .social-links {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .project-card {
        page-break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ccc;
        margin-bottom: var(--spacing-md);
    }
    
    .project-card img {
        max-height: 300px;
    }
}