* {
    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 */
#main-content {
    max-width: 1000px;
    margin: 0 auto;
    padding: var(--spacing-lg);
    flex: 1;
    width: 100%;
}

section {
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-xl) var(--spacing-lg);
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    box-shadow: 0 8px 40px rgba(58, 52, 47, 0.12);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

section:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 50px rgba(58, 52, 47, 0.18);
}

/* bio section */
.bio {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.8), rgba(232, 226, 220, 0.5));
    text-align: center;
}

.bio figure {
    margin-bottom: var(--spacing-lg);
}

.bio img {
    width: clamp(180px, 35vw, 280px);
    height: clamp(180px, 35vw, 280px);
    border-radius: 50%;
    object-fit: cover;
    border: 6px solid var(--color-light);
    box-shadow: 0 12px 45px rgba(58, 52, 47, 0.25);
    transition: transform var(--transition-slow), box-shadow var(--transition-slow);
    margin: 0 auto;
    display: block;
}

.bio img:hover {
    transform: scale(1.05) rotate(2deg);
    box-shadow: 0 18px 60px rgba(58, 52, 47, 0.35);
}

.bio figcaption {
    margin-top: var(--spacing-md);
    font-size: clamp(0.95rem, 2vw, 1.05rem);
    color: var(--color-medium-dark);
    font-style: italic;
    font-weight: 500;
}

.bio p {
    text-align: center;
    font-size: clamp(1.05rem, 2.5vw, 1.15rem);
    line-height: 1.9;
    max-width: 800px;
    margin: 0 auto;
    margin-bottom: var(--spacing-md);
}

.bio p:last-of-type {
    margin-bottom: 0;
}

/* skills section */
.skills {
    background: linear-gradient(135deg, rgba(232, 226, 220, 0.6), rgba(255, 255, 255, 0.8));
}

.skills ul {
    list-style: none;
    padding: 0;
    display: grid;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.skills li {
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.7);
    border-left: 4px solid var(--color-accent);
    border-radius: var(--radius-md);
    font-size: clamp(1rem, 2.5vw, 1.1rem);
    color: var(--color-dark);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.skills li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 0;
    background: linear-gradient(90deg, rgba(157, 139, 126, 0.1), transparent);
    transition: width var(--transition-normal);
}

.skills li:hover {
    background: rgba(255, 255, 255, 0.95);
    border-left-width: 6px;
    padding-left: calc(var(--spacing-md) + 2px);
    transform: translateX(8px);
    box-shadow: -4px 4px 20px rgba(58, 52, 47, 0.15);
}

.skills li:hover::before {
    width: 100%;
}

.skills li strong {
    color: var(--color-darkest);
    font-weight: 600;
    display: inline-block;
    margin-right: var(--spacing-xs);
}

/* goals section */
.goals {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.85), rgba(212, 204, 196, 0.4));
    position: relative;
    overflow: hidden;
}

.goals::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(157, 139, 126, 0.1), transparent);
    border-radius: 50%;
    pointer-events: none;
}

.goals p {
    font-size: clamp(1.05rem, 2.5vw, 1.15rem);
    line-height: 1.9;
    text-align: center;
    max-width: 750px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

/* 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);
    }
    
    section {
        padding: var(--spacing-lg) var(--spacing-md);
    }
    
    .bio img {
        width: clamp(150px, 40vw, 220px);
        height: clamp(150px, 40vw, 220px);
    }
}

@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);
    }
    
    section {
        padding: var(--spacing-md) var(--spacing-sm);
        margin-bottom: var(--spacing-lg);
    }
    
    .bio img {
        width: clamp(130px, 45vw, 180px);
        height: clamp(130px, 45vw, 180px);
    }
    
    .skills ul {
        gap: var(--spacing-sm);
    }
    
    .skills li {
        padding: var(--spacing-sm);
    }
    
    .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);
    }
    
    section {
        padding: var(--spacing-xs) var(--spacing-sm);
    }
    
    .bio img {
        width: clamp(100px, 40vw, 140px);
        height: clamp(100px, 40vw, 140px);
    }
    
    h2 {
        font-size: clamp(1.35rem, 5vw, 1.75rem);
    }
    
    h3 {
        font-size: clamp(1.1rem, 4vw, 1.35rem);
    }
    
    .skills li {
        padding: var(--spacing-xs);
        font-size: 0.9rem;
    }
    
    .back-to-top {
        bottom: var(--spacing-sm);
        right: var(--spacing-sm);
        width: 40px;
        height: 40px;
        font-size: 1.15rem;
    }
}

@media screen and (min-width: 1200px) {
    #main-content {
        max-width: 1100px;
    }
    
    .skills ul {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media screen and (min-width: 1400px) {
    #main-content {
        max-width: 1200px;
    }
}

@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;
    }
    
    section,
    .skills li {
        border: 2px solid var(--color-darkest);
    }
}

@media print {
    .site-header,
    .back-to-top,
    .site-footer .social-links {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
    
    section {
        page-break-inside: avoid;
        box-shadow: none;
    }
    
    .bio img {
        width: 150px;
        height: 150px;
    }
}