/* ===== Design Tokens ===== */
:root {
  /* Colors */
  --color-primary: #2D3436;
  --color-accent: #E17055;
  --color-bg: #FAFAF8;
  --color-bg-secondary: #F5F5F3;
  --color-text: #2D3436;
  --color-text-secondary: #636E72;
  --color-text-light: #B2BEC3;
  --color-border: #DFE6E9;
  --color-white: #FFFFFF;
  
  /* Typography */
  --font-serif: 'Noto Serif SC', 'Georgia', serif;
  --font-sans: 'Noto Sans SC', 'Helvetica Neue', sans-serif;
  
  /* Font Sizes */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;
  
  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  
  /* Layout */
  --max-width: 1200px;
  --header-height: 72px;
}

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

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

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-primary);
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-4xl); }
h3 { font-size: var(--text-3xl); }
h4 { font-size: var(--text-2xl); }
h5 { font-size: var(--text-xl); }
h6 { font-size: var(--text-lg); }

p {
  margin-bottom: var(--space-4);
}

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

/* ===== Header ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(250, 250, 248, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  transition: transform var(--transition-base);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.header__logo {
  font-family: var(--font-serif);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.header__logo-icon {
  width: 32px;
  height: 32px;
  background: var(--color-accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-white);
  font-size: var(--text-sm);
}

.header__nav {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.header__nav-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  position: relative;
  padding: var(--space-2) 0;
}

.header__nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

.header__nav-link:hover,
.header__nav-link--active {
  color: var(--color-primary);
}

.header__nav-link:hover::after,
.header__nav-link--active::after {
  width: 100%;
}

/* Mobile Menu Button */
.header__menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-2);
}

.header__menu-btn span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-primary);
  transition: transform var(--transition-fast);
}

/* ===== Main Content ===== */
.main {
  padding-top: var(--header-height);
  min-height: 100vh;
}

/* ===== Hero Section ===== */
.hero {
  padding: var(--space-24) 0 var(--space-16);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  right: -10%;
  width: 60%;
  height: 100%;
  background: linear-gradient(135deg, rgba(225, 112, 85, 0.08) 0%, rgba(225, 112, 85, 0.02) 100%);
  border-radius: 0 0 0 50%;
  z-index: -1;
}

.hero__content {
  max-width: 700px;
}

.hero__tag {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  background: rgba(225, 112, 85, 0.1);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-6);
}

.hero__title {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  margin-bottom: var(--space-6);
  line-height: 1.2;
}

.hero__title span {
  color: var(--color-accent);
}

.hero__subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-8);
}

.hero__cta {
  display: flex;
  gap: var(--space-4);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.btn--primary {
  background: var(--color-primary);
  color: var(--color-white);
}

.btn--primary:hover {
  background: var(--color-accent);
  color: var(--color-white);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn--outline {
  border: 1.5px solid var(--color-border);
  color: var(--color-text);
}

.btn--outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ===== Section Styles ===== */
.section {
  padding: var(--space-16) 0;
}

.section__header {
  margin-bottom: var(--space-12);
}

.section__tag {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
}

.section__title {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-4);
}

.section__desc {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  max-width: 600px;
}

/* ===== Featured Articles ===== */
.featured {
  background: var(--color-bg-secondary);
}

.featured__grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--space-8);
}

.article-card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.article-card--large {
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.article-card__image {
  aspect-ratio: 16/10;
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-border) 100%);
  position: relative;
  overflow: hidden;
}

.article-card--large .article-card__image {
  aspect-ratio: auto;
  min-height: 300px;
}

.article-card__image-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-4xl);
  color: var(--color-text-light);
}

.article-card__content {
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
}

.article-card__category {
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
}

.article-card__title {
  font-size: var(--text-xl);
  margin-bottom: var(--space-3);
  line-height: 1.4;
}

.article-card--large .article-card__title {
  font-size: var(--text-2xl);
}

.article-card__excerpt {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-4);
  flex-grow: 1;
}

.article-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-text-light);
}

.article-card__meta-item {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

/* ===== Categories ===== */
.categories__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-6);
}

.category-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-align: center;
  transition: all var(--transition-base);
}

.category-card:hover {
  border-color: var(--color-accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.category-card__icon {
  width: 56px;
  height: 56px;
  margin: 0 auto var(--space-4);
  background: linear-gradient(135deg, rgba(225, 112, 85, 0.1) 0%, rgba(225, 112, 85, 0.05) 100%);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-2xl);
}

.category-card__title {
  font-size: var(--text-base);
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.category-card__count {
  font-size: var(--text-sm);
  color: var(--color-text-light);
}

/* ===== Recent Articles ===== */
.recent__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.article-item {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: var(--space-6);
  padding-bottom: var(--space-6);
  border-bottom: 1px solid var(--color-border);
}

.article-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.article-item__image {
  aspect-ratio: 4/3;
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-border) 100%);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-2xl);
  color: var(--color-text-light);
}

.article-item__content {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.article-item__category {
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-accent);
  margin-bottom: var(--space-2);
}

.article-item__title {
  font-size: var(--text-lg);
  margin-bottom: var(--space-2);
  line-height: 1.4;
}

.article-item__excerpt {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-3);
}

.article-item__meta {
  font-size: var(--text-xs);
  color: var(--color-text-light);
}

/* ===== About Section ===== */
.about-preview {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: var(--space-12);
  align-items: center;
}

.about-preview__image {
  aspect-ratio: 4/5;
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-border) 100%);
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-5xl);
  color: var(--color-text-light);
}

.about-preview__content h3 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-4);
}

.about-preview__content p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-6);
}

.about-preview__stats {
  display: flex;
  gap: var(--space-8);
  margin-top: var(--space-8);
}

.stat {
  text-align: center;
}

.stat__number {
  font-family: var(--font-serif);
  font-size: var(--text-3xl);
  font-weight: 700;
  color: var(--color-accent);
}

.stat__label {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

/* ===== Footer ===== */
.footer {
  background: var(--color-primary);
  color: var(--color-white);
  padding: var(--space-12) 0 var(--space-8);
}

.footer__inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-12);
  margin-bottom: var(--space-12);
}

.footer__brand h4 {
  font-size: var(--text-xl);
  color: var(--color-white);
  margin-bottom: var(--space-4);
}

.footer__brand p {
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.7);
  line-height: 1.8;
}

.footer__column h5 {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--space-4);
}

.footer__column ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer__column a {
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.7);
}

.footer__column a:hover {
  color: var(--color-white);
}

.footer__bottom {
  padding-top: var(--space-8);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.footer__copyright {
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.5);
}

.footer__social {
  display: flex;
  gap: var(--space-4);
}

.footer__social a {
  width: 36px;
  height: 36px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-sm);
  color: var(--color-white);
  transition: background var(--transition-fast);
}

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

/* ===== Beian (备案号) ===== */
.footer__beian {
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.5);
}

.footer__beian a {
  color: rgba(255, 255, 255, 0.5);
  transition: color var(--transition-fast);
}

.footer__beian a:hover {
  color: var(--color-white);
}

/* ===== Articles Page ===== */
.page-header {
  padding: var(--space-16) 0 var(--space-12);
  text-align: center;
}

.page-header__title {
  font-size: var(--text-4xl);
  margin-bottom: var(--space-4);
}

.page-header__desc {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  max-width: 500px;
  margin: 0 auto;
}

/* Filter Tabs */
.filter-tabs {
  display: flex;
  justify-content: center;
  gap: var(--space-2);
  margin-bottom: var(--space-12);
  flex-wrap: wrap;
}

.filter-tab {
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.filter-tab:hover,
.filter-tab--active {
  background: var(--color-primary);
  color: var(--color-white);
}

/* Articles Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-8);
}

/* ===== About Page ===== */
.about-hero {
  padding: var(--space-20) 0;
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: var(--space-16);
  align-items: center;
}

.about-hero__image {
  aspect-ratio: 1;
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-border) 100%);
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 6rem;
  color: var(--color-text-light);
}

.about-hero__content h1 {
  font-size: var(--text-4xl);
  margin-bottom: var(--space-6);
}

.about-hero__content p {
  color: var(--color-text-secondary);
  font-size: var(--text-lg);
  line-height: 1.8;
}

/* Skills Section */
.skills__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.skill-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  transition: all var(--transition-base);
}

.skill-card:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md);
}

.skill-card__icon {
  width: 48px;
  height: 48px;
  background: rgba(225, 112, 85, 0.1);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-xl);
  margin-bottom: var(--space-4);
}

.skill-card__title {
  font-size: var(--text-lg);
  margin-bottom: var(--space-3);
}

.skill-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* Contact Section */
.contact {
  background: var(--color-bg-secondary);
}

.contact__content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
}

.contact__info h3 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-4);
}

.contact__info p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-8);
}

.contact__methods {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.contact-method {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.contact-method__icon {
  width: 44px;
  height: 44px;
  background: var(--color-white);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
}

.contact-method__text {
  font-size: var(--text-sm);
}

.contact-method__label {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-1);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .featured__grid {
    grid-template-columns: 1fr;
  }
  
  .article-card--large {
    grid-template-columns: 1fr;
  }
  
  .categories__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .about-preview {
    grid-template-columns: 1fr;
  }
  
  .footer__inner {
    grid-template-columns: 1fr 1fr;
  }
  
  .about-hero {
    grid-template-columns: 1fr;
  }
  
  .skills__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .contact__content {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }
  
  .header__nav {
    display: none;
  }
  
  .header__menu-btn {
    display: flex;
  }
  
  .hero {
    padding: var(--space-16) 0 var(--space-12);
  }
  
  .hero__title {
    font-size: var(--text-3xl);
  }
  
  .hero__cta {
    flex-direction: column;
  }
  
  .categories__grid {
    grid-template-columns: 1fr;
  }
  
  .article-item {
    grid-template-columns: 1fr;
  }
  
  .articles-grid {
    grid-template-columns: 1fr;
  }
  
  .footer__inner {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }
  
  .footer__bottom {
    flex-direction: column;
    gap: var(--space-4);
  }
  
  .about-hero__image {
    max-width: 300px;
    margin: 0 auto;
  }
  
  .skills__grid {
    grid-template-columns: 1fr;
  }
  
  .about-preview__stats {
    flex-wrap: wrap;
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--space-4);
  }
  
  .section {
    padding: var(--space-12) 0;
  }
  
  .hero__cta .btn {
    width: 100%;
    justify-content: center;
  }
}