/* === Theme Variables === */
:root {
    --bg: #ffffff;
    --bg-secondary: #f9f9f9;
    --text: #111111;
    --text-secondary: #555555;
    --border: #e8e8e8;
    --tag-bg: #f3f3f3;
    --tag-text: #444444;
    --tag-border: #e0e0e0;
    --link: #111111;
    --link-hover: #555555;
    --toggle-bg: #f3f3f3;
    --transition: 0.2s ease;
}

[data-theme="dark"] {
    --bg: #0f0f0f;
    --bg-secondary: #161616;
    --text: #e8e8e8;
    --text-secondary: #999999;
    --border: #2a2a2a;
    --tag-bg: #1a1a1a;
    --tag-text: #bbbbbb;
    --tag-border: #2a2a2a;
    --link: #e8e8e8;
    --link-hover: #999999;
    --toggle-bg: #1a1a1a;
}

/* === Reset === */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* === Base === */
html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    font-size: 16px;
    line-height: 1.7;
    color: var(--text);
    background-color: var(--bg);
    transition: background-color var(--transition), color var(--transition);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* === Skip Link (a11y) === */
.skip-link {
    position: absolute;
    top: -100%;
    left: 16px;
    padding: 8px 16px;
    background: var(--text);
    color: var(--bg);
    border-radius: 4px;
    z-index: 100;
    font-size: 14px;
    text-decoration: none;
}

.skip-link:focus {
    top: 16px;
}

/* === Header === */
header {
    width: 100%;
    max-width: 640px;
    margin: 0 auto;
    padding: 24px 24px 0;
}

header nav {
    display: flex;
    justify-content: flex-end;
    align-items: center;
}

/* === Theme Toggle === */
#theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--toggle-bg);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition);
}

#theme-toggle:hover {
    color: var(--text);
    border-color: var(--text-secondary);
}

[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }
[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }

/* === Main === */
main {
    flex: 1;
    width: 100%;
    max-width: 640px;
    margin: 0 auto;
    padding: 0 24px;
}

/* === Hero === */
.hero {
    padding: 40px 0 32px;
}

.hero h1 {
    font-size: 36px;
    font-weight: 600;
    letter-spacing: -0.03em;
    line-height: 1.2;
    margin-bottom: 8px;
}

.role {
    font-size: 17px;
    color: var(--text-secondary);
    font-weight: 400;
    margin-bottom: 24px;
}

.bio {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.75;
    max-width: 540px;
}

/* === Sections === */
section + section {
    padding-top: 36px;
}

.section-title {
    font-size: 13px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

/* === Experience === */
.experience {
    display: flex;
    flex-direction: column;
    gap: 0;
    border-left: 2px solid var(--border);
    padding-left: 20px;
}

.exp-item {
    position: relative;
    padding: 12px 0;
}

.exp-item::before {
    content: '';
    position: absolute;
    left: -25px;
    top: 18px;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--text-secondary);
    border: 2px solid var(--bg);
    transition: background var(--transition), border-color var(--transition);
}

.exp-item:first-child::before {
    background: var(--text);
    box-shadow: 0 0 0 3px var(--bg), 0 0 0 4px var(--text);
}

.exp-header {
    display: flex;
    align-items: center;
    gap: 10px;
}

.exp-company {
    font-size: 15px;
    font-weight: 500;
    color: var(--text);
}

.exp-current {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    background: var(--tag-bg);
    border: 1px solid var(--tag-border);
    padding: 2px 8px;
    border-radius: 4px;
}

.exp-description {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-top: 4px;
}

/* === Skills === */
.skills {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    list-style: none;
}

.skills li {
    font-size: 14px;
    font-weight: 450;
    color: var(--tag-text);
    background: var(--tag-bg);
    border: 1px solid var(--tag-border);
    padding: 6px 14px;
    border-radius: 6px;
    transition: all var(--transition);
}

.skills li:hover {
    color: var(--text);
    border-color: var(--text-secondary);
}

/* === Interests === */
.interests {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    list-style: none;
}

.interests li {
    font-size: 14px;
    font-weight: 450;
    color: var(--tag-text);
    background: var(--tag-bg);
    border: 1px solid var(--tag-border);
    padding: 6px 14px;
    border-radius: 6px;
    transition: all var(--transition);
}

.interests li:hover {
    color: var(--text);
    border-color: var(--text-secondary);
}

/* === Social === */
.social {
    display: flex;
    gap: 12px;
    list-style: none;
}

.social a {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 15px;
    font-weight: 450;
    color: var(--link);
    text-decoration: none;
    padding: 10px 18px;
    border: 1px solid var(--border);
    border-radius: 8px;
    transition: all var(--transition);
}

.social a:hover {
    background: var(--tag-bg);
    border-color: var(--text-secondary);
}

.social a svg {
    flex-shrink: 0;
}

/* === Footer === */
footer {
    width: 100%;
    max-width: 640px;
    margin: 0 auto;
    padding: 64px 24px 40px;
}

footer p {
    font-size: 13px;
    color: var(--text-secondary);
}

/* === Responsive === */
@media (max-width: 480px) {
    header {
        padding-top: 24px;
    }

    .hero {
        padding: 56px 0 40px;
    }

    .hero h1 {
        font-size: 28px;
    }

    .role {
        font-size: 16px;
    }

    .bio {
        font-size: 15px;
    }

    .social {
        flex-direction: column;
    }

    .social a {
        justify-content: center;
    }
}