/* --- Apple-Style Redesign by Wish (Final Version with Enhanced Footer) --- */

/* 1. FONT & VARIABLES */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Noto+Serif+SC:wght@400;600&display=swap');
:root {
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-family-serif: 'Noto Serif SC', serif;
    --bg-color: #ffffff;
    --text-color: #1d1d1f;
    --text-color-secondary: #6e6e73;
    --card-bg-color: #f5f5f7;
    --link-color: #0066cc;
    --border-color: #d2d2d7;
    --header-bg-color: rgba(255, 255, 255, 0.8);
    --border-radius: 18px;
    --max-width: 1080px;
}
[data-theme='dark'] {
    --bg-color: #000000;
    --text-color: #f5f5f7;
    --text-color-secondary: #86868b;
    --card-bg-color: #1d1d1f;
    --link-color: #2997ff;
    --border-color: #424245;
    --header-bg-color: rgba(29, 29, 31, 0.8);
}

/* 2. GLOBAL RESET & BASE STYLES */
* { box-sizing: border-box; margin: 0; padding: 0; }
html {
    scroll-behavior: smooth;
    overflow-y: scroll;
}
body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 17px;
    line-height: 1.6;
    font-weight: 400;
    transition: background-color 0.3s ease, color 0.3s ease;
    overflow-x: hidden;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 22px; }
main {
    flex-grow: 1; /* 让main内容区占据所有可用空间 */
}

/* 3. HEADER */
.main-header {
    background-color: var(--header-bg-color);
    -webkit-backdrop-filter: blur(20px);
    backdrop-filter: blur(20px);
    position: sticky;
    top: 0;
    z-index: 1000;
    width: 100%;
    border-bottom: 1px solid var(--border-color);
    transition: transform 0.4s cubic-bezier(0.2, 0, 0, 1), background-color 0.3s ease, border-color 0.3s ease;
}
.main-header.is-hidden {
    transform: translateY(-100%);
}
.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 52px;
}
.logo-link {
    display: flex;
    align-items: center;
    height: 100%;
    color: var(--text-color);
    transition: color 0.3s ease;
}
.logo-link:hover {
    color: var(--link-color);
}
[data-theme='dark'] .logo-link {
    color: #ffffff;
}
.logo-image {
    height: 20px;
    width: auto;
}
nav {
    display: flex;
    align-items: center;
    opacity: 0;
    animation: fadeInNav 0.4s ease 50ms forwards;
}
nav a {
    position: relative;
    color: var(--text-color);
    font-weight: 500;
    text-decoration: none;
    font-size: 14px;
    margin-left: 30px;
    transition: color 0.3s ease;
    border-radius: 4px;
}
nav a:focus { outline: none; }
nav a:focus-visible { box-shadow: 0 0 0 2px var(--link-color); }
nav a::after {
    content: ''; position: absolute; width: 100%; height: 2px; bottom: -8px; left: 0;
    background-color: var(--link-color); opacity: 0; transition: opacity 0.3s ease-in-out;
}
nav a.active::after,
nav a:hover::after,
nav a:focus::after {
    opacity: 1;
}
nav a.active,
nav a:hover {
    color: var(--link-color);
}
.theme-toggle {
    background-color: transparent; border: none; cursor: pointer; display: flex; align-items: center; justify-content: center; padding: 5px; margin-left: 20px; border-radius: 50%; width: 36px; height: 36px; transition: background-color 0.3s ease, transform 0.3s ease;
}
.theme-toggle:hover { background-color: var(--card-bg-color); transform: scale(1.1); }
.theme-toggle svg {
    width: 20px;
    height: 20px;
    color: var(--text-color-secondary);
    transition: transform 0.5s ease, color 0.3s ease;
    transform: rotate(0deg) !important;
}
.theme-toggle:hover svg {
    transform: rotate(90deg) !important;
}

/* 4. FOOTER (New & Enhanced) */
.main-footer {
    padding: 40px 0;
    background-color: var(--card-bg-color);
    border-top: 1px solid var(--border-color);
    font-size: 14px;
    color: var(--text-color-secondary);
    flex-shrink: 0;
}
.footer-grid {
    display: flex;
    flex-direction: column;
    gap: 20px;
}
.footer-top, .footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}
.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 10px 20px;
}
.footer-links a {
    color: var(--text-color-secondary);
    text-decoration: none;
    transition: color 0.3s ease;
}
.footer-links a:hover {
    color: var(--text-color);
}
.footer-socials {
    display: flex;
    gap: 15px;
}
.footer-socials a {
    display: inline-block;
}
.footer-socials svg {
    width: 20px;
    height: 20px;
    color: var(--text-color-secondary);
    transition: color 0.3s ease, transform 0.3s ease;
}
.footer-socials a:hover svg {
    color: var(--text-color);
    transform: scale(1.1);
}
.footer-bottom {
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.section { padding: 80px 0; text-align: center; }
.section-hero { min-height: 600px; display: flex; align-items: center; justify-content: center; padding: 60px 0; background-size: cover; background-position: center; background-image: url('../images/hero-background.jpg'); }
.section-compact-top { padding-top: 20px; }
.section-hero .headline, .section-hero .subheadline, .section-hero .cta-link { color: #ffffff; text-shadow: 0 2px 10px rgba(0,0,0,0.5); }
.section-hero .cta-link { color: #6bf; }
.headline { font-size: 56px; font-weight: 700; line-height: 1.1; letter-spacing: -0.01em; margin-bottom: 20px; color: var(--text-color); }
.subheadline { font-size: 24px; font-weight: 400; line-height: 1.3; max-width: 680px; margin: 0 auto; color: var(--text-color-secondary); }
.section-divider { margin-top: 100px; }
.cta-link { display: inline-block; color: var(--link-color); text-decoration: none; font-size: 19px; margin-top: 25px; transition: color 0.3s ease; }
.cta-link::after { content: ' ›'; }
.cta-link:hover { text-decoration: underline; }
.portfolio-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 30px; margin-top: 60px; }
.portfolio-card { background-color: var(--card-bg-color); border-radius: var(--border-radius); color: var(--text-color); display: flex; flex-direction: column; overflow: hidden; transition: transform 0.3s ease, background-color 0.3s ease; text-decoration: none; }
.portfolio-card:hover { transform: scale(1.02); }
.portfolio-card img { display: block; width: 100%; height: auto; aspect-ratio: 4 / 3; object-fit: cover; }
.card-content { padding: 30px; flex-grow: 1; text-align: left;}
.card-content .project-title { font-size: 24px; font-weight: 600; margin-bottom: 10px; color: var(--text-color); }
.card-content .project-description { color: var(--text-color-secondary); }
.category-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 30px; margin-top: 60px; }
.category-card { position: relative; display: block; text-decoration: none; color: #fff; border-radius: var(--border-radius); overflow: hidden; aspect-ratio: 4 / 3; transition: transform 0.3s ease; }
.category-card:hover { transform: scale(1.03); }
.category-card-img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.5s ease; }
.category-card:hover .category-card-img { transform: scale(1.1); }
.category-card-overlay { position: absolute; inset: 0; background: linear-gradient(to top, rgba(0,0,0,0.8) 0%, rgba(0,0,0,0) 60%); padding: 30px; display: flex; flex-direction: column; justify-content: flex-end; }
.category-card-title { font-size: 28px; font-weight: 600; }
.category-card-description { font-size: 16px; opacity: 0.8; }
.avatar { width: 120px; height: 120px; border-radius: 50%; object-fit: cover; margin: 0 auto 30px; display: block; }
.content-layout { max-width: 800px; margin: 60px auto 0; text-align: left; }
.content-layout p { font-size: 19px; margin-bottom: 20px; color: var(--text-color-secondary); }
.contact-form { background-color: transparent; padding: 0; box-shadow: none; max-width: 600px; }
.form-group input, .form-group textarea { background-color: var(--card-bg-color); border: 1px solid var(--border-color); font-size: 16px; border-radius: 12px; padding: 12px 15px; width: 100%; font-family: var(--font-family); color: var(--text-color); transition: border-color 0.3s ease, box-shadow 0.3s ease; }
.form-group input:focus, .form-group textarea:focus { outline: none; border-color: var(--link-color); box-shadow: 0 0 0 4px rgba(0, 102, 204, 0.2); }
.form-group { margin-bottom: 25px; }
.form-group label { display: block; font-size: 14px; font-weight: 500; margin-bottom: 8px; color: var(--text-color-secondary); text-align: left; }
.form-group input::placeholder, .form-group textarea::placeholder { color: #a1a1a6; }
[data-theme='dark'] .form-group input::placeholder, [data-theme='dark'] .form-group textarea::placeholder { color: #6e6e73; }
.submit-button { display: block; width: 100%; padding: 14px; border: none; border-radius: 12px; background-color: var(--link-color); color: #ffffff; font-size: 16px; font-weight: 600; font-family: var(--font-family); cursor: pointer; transition: background-color 0.3s ease, transform 0.2s ease; }
.submit-button:hover { filter: brightness(1.1); }
.submit-button:active { transform: scale(0.98); }
.notes-list { margin-top: 60px; border-top: 1px solid var(--border-color); }
.note-item { display: block; text-decoration: none; padding: 30px 0; border-bottom: 1px solid var(--border-color); transition: background-color 0.2s ease; text-align: left;}
.note-title { font-size: 24px; font-weight: 600; color: var(--text-color); margin-bottom: 10px; transition: color 0.3s ease; }
.note-item:hover .note-title { color: var(--link-color); }
.note-excerpt { font-size: 17px; color: var(--text-color-secondary); margin-bottom: 15px; }
.note-date { font-size: 14px; color: var(--text-color-secondary); opacity: 0.8; }
.internal-link { color: var(--link-color); text-decoration: none; font-weight: 500; position: relative; white-space: nowrap; }
.internal-link::after { content: ''; position: absolute; width: 100%; height: 1px; bottom: -2px; left: 0; background-color: var(--link-color); opacity: 0.5; transform: scaleX(0); transform-origin: right; transition: transform 0.3s ease-out; }
.internal-link:hover::after { transform: scaleX(1); transform-origin: left; }
.note-article-layout h1, .prose-article-layout h1 { font-size: 40px; font-weight: 700; margin-bottom: 10px; text-align: left; }
.note-article-layout .author-line, .prose-article-layout .author-line { font-size: 16px; color: var(--text-color-secondary); margin-bottom: 40px; text-align: left; }
.note-article-layout h2, .prose-article-layout h2 { font-size: 28px; font-weight: 600; margin-top: 40px; margin-bottom: 15px; text-align: left; color: var(--text-color); }
.note-article-layout ul, .prose-article-layout ul { list-style-position: inside; padding-left: 0; text-align: left; }
.note-article-layout li, .prose-article-layout li { margin-bottom: 10px; color: var(--text-color-secondary); }
.note-article-layout code { background-color: var(--card-bg-color); padding: 2px 6px; border-radius: 6px; font-size: 0.9em; font-family: "SF Mono", "Fira Code", "Consolas", monospace; }
.note-article-layout .back-link-wrapper, .prose-article-layout .back-link-wrapper { margin-top: 80px; text-align: center; border-top: 1px solid var(--border-color); padding-top: 40px; }
.back-link { display: inline-flex; align-items: center; gap: 8px; background-color: var(--card-bg-color); color: var(--text-color-secondary); font-size: 16px; font-weight: 500; text-decoration: none; padding: 12px 24px; border-radius: 50px; transition: all 0.3s ease; }
.back-link:hover { background-color: var(--border-color); color: var(--text-color); transform: translateY(-3px); box-shadow: 0 4px 15px rgba(0,0,0,0.1); }
[data-theme='dark'] .back-link:hover { box-shadow: 0 4px 15px rgba(0,0,0,0.2); }
.back-link svg { width: 16px; height: 16px; transition: transform 0.3s ease; }
.back-link:hover svg { transform: translateX(-4px); }
.prose-article-layout { max-width: 720px; text-align: justify; }
.prose-article-layout h1, .prose-article-layout h2, .prose-article-layout p { font-family: var(--font-family-serif); text-align: left; }
.prose-article-layout h1 { font-size: 36px; font-weight: 600; }
.prose-article-layout p { font-size: 18px; line-height: 2; }
.projects-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 25px; margin-top: 60px; }
.project-item-card { background-color: var(--card-bg-color); border-radius: var(--border-radius); text-decoration: none; color: var(--text-color); overflow: hidden; transition: transform 0.3s ease, box-shadow 0.3s ease; border: 1px solid var(--border-color); }
.project-item-card:hover { transform: translateY(-5px); box-shadow: 0 8px 25px rgba(0,0,0,0.1); }
[data-theme='dark'] .project-item-card:hover { box-shadow: 0 8px 25px rgba(0,0,0,0.3); }
.project-item-card img { display: block; width: 100%; height: 180px; object-fit: cover; border-bottom: 1px solid var(--border-color); }
.project-item-content { padding: 20px; text-align: left; }
.project-item-content h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; color: var(--text-color); }
.project-item-content p { font-size: 14px; color: var(--text-color-secondary); line-height: 1.5; }
.photo-grid {
    margin-top: 60px;
    column-count: 2;
    column-gap: 20px;
}
.photo-item {
    margin-bottom: 20px;
    break-inside: avoid;
    position: relative;
    overflow: hidden;
    border-radius: var(--border-radius);
    line-height: 0;
}
.photo-item img {
    width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}
.photo-item:hover img {
    transform: scale(1.03);
    box-shadow: 0 10px 30px rgba(0,0,0,0.15);
}
[data-theme='dark'] .photo-item:hover img {
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}
.photo-caption {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 20px;
    background: linear-gradient(to top, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0) 100%);
    color: #fff;
    font-size: 16px;
    font-weight: 500;
    text-align: left;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.4s ease, transform 0.4s ease;
}
.photo-item:hover .photo-caption {
    opacity: 1;
    transform: translateY(0);
}
.photo-item.align-right img {
    object-position: 80% 50%;
}
@keyframes fadeInNav {
    from { opacity: 0; }
    to { opacity: 1; }
}
@media (max-width: 900px) {
    .projects-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
    body { font-size: 16px; line-height: 1.65; }
    .container { padding: 0 20px; }
    .main-header { padding: 15px 0; background-color: var(--card-bg-color); }
    .main-header .container { flex-direction: column; gap: 15px; }
    nav { width: 100%; display: flex; justify-content: space-around; }
    nav a { margin-left: 0; font-size: 14px; }
    .theme-toggle { position: absolute; top: 7px; right: 15px; }
    .section { padding: 60px 0; }
    .section-hero { min-height: 450px; padding: 40px 0; }
    .headline { font-size: 36px; line-height: 1.2; }
    .subheadline { font-size: 18px; line-height: 1.4; }
    .portfolio-grid { grid-template-columns: 1fr; }
    .category-grid { grid-template-columns: 1fr; }
    .content-layout { margin-top: 40px; text-align: justify; }
    .note-title { font-size: 20px; }
    .note-excerpt { font-size: 16px; }
    .projects-grid { grid-template-columns: 1fr; }
    .prose-article-layout h1 { font-size: 30px; }
    .prose-article-layout p { font-size: 17px; line-height: 1.9; }
    .section-divider { margin-top: 80px; }
    .photo-grid { column-count: 1; }
    .footer-top, .footer-bottom { flex-direction: column; gap: 15px; }
    .footer-links { order: 2; margin-left: 0; }
    .footer-socials { order: 1; margin-left: 0; }
}