/* ===== 全局样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary: #0891b2;
    --accent: #059669;
    --dark: #1e293b;
    --dark-light: #334155;
    --gray: #64748b;
    --gray-light: #94a3b8;
    --gray-lighter: #cbd5e1;
    --bg: #f8fafc;
    --bg-white: #ffffff;
    --bg-card: #ffffff;
    --border: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #0891b2 100%);
    --gradient-accent: linear-gradient(135deg, #059669 0%, #10b981 100%);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--dark);
    background: var(--bg);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    border-bottom-color: var(--border);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--dark);
    font-weight: 700;
    font-size: 20px;
}

.logo-icon {
    font-size: 28px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 8px;
}

.nav-link {
    display: block;
    padding: 10px 16px;
    text-decoration: none;
    color: var(--gray);
    font-weight: 500;
    font-size: 15px;
    border-radius: 8px;
    transition: all 0.2s ease;
}

.nav-link:hover {
    color: var(--primary);
    background: rgba(37, 99, 235, 0.08);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
}

.hamburger span {
    width: 24px;
    height: 2px;
    background: var(--dark);
    border-radius: 2px;
    transition: all 0.3s ease;
}

/* ===== Hero 区域 ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    background: linear-gradient(180deg, #eff6ff 0%, #f8fafc 100%);
    padding-top: 72px;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
    pointer-events: none;
}

.floating-chart {
    position: absolute;
    border-radius: 16px;
    background: white;
    box-shadow: var(--shadow-lg);
    opacity: 0.6;
    animation: float 6s ease-in-out infinite;
}

.chart-1 {
    width: 200px;
    height: 150px;
    top: 15%;
    left: 5%;
    background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
    animation-delay: 0s;
}

.chart-2 {
    width: 180px;
    height: 120px;
    top: 60%;
    right: 8%;
    background: linear-gradient(135deg, #cffafe 0%, #a5f3fc 100%);
    animation-delay: 2s;
}

.chart-3 {
    width: 150px;
    height: 150px;
    bottom: 15%;
    left: 15%;
    background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%);
    animation-delay: 4s;
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(3deg); }
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    border-radius: 50px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 24px;
}

.badge-dot {
    width: 8px;
    height: 8px;
    background: var(--accent);
    border-radius: 50%;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 16px;
    color: var(--dark);
}

.hero-title .highlight {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 24px;
    font-weight: 600;
    color: var(--dark-light);
    margin-bottom: 16px;
}

.hero-description {
    font-size: 17px;
    color: var(--gray);
    margin-bottom: 32px;
    max-width: 560px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: 12px;
    font-weight: 600;
    font-size: 16px;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.5);
}

.btn-secondary {
    background: white;
    color: var(--dark);
    border: 2px solid var(--border);
}

.btn-secondary:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: translateY(-2px);
}

.btn-large {
    padding: 16px 32px;
    font-size: 17px;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.stat-item {
    text-align: left;
}

.stat-number {
    font-size: 28px;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 4px;
}

.stat-label {
    font-size: 14px;
    color: var(--gray);
    font-weight: 500;
}

.hero-visual {
    display: flex;
    justify-content: center;
}

.chart-card {
    background: white;
    border-radius: 20px;
    padding: 24px;
    box-shadow: var(--shadow-xl);
    width: 100%;
    max-width: 360px;
}

.chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.chart-title {
    font-weight: 700;
    font-size: 16px;
    color: var(--dark);
}

.chart-status {
    font-size: 12px;
    font-weight: 600;
    color: var(--accent);
}

.chart-status.live {
    animation: pulse 2s infinite;
}

.chart-body {
    height: 180px;
    display: flex;
    align-items: flex-end;
}

.mini-bars {
    display: flex;
    align-items: flex-end;
    gap: 8px;
    width: 100%;
    height: 100%;
}

.mini-bar {
    flex: 1;
    background: var(--gradient-primary);
    border-radius: 6px 6px 0 0;
    animation: barGrow 1.5s ease-out forwards;
    opacity: 0;
}

.mini-bar:nth-child(1) { animation-delay: 0.1s; }
.mini-bar:nth-child(2) { animation-delay: 0.2s; }
.mini-bar:nth-child(3) { animation-delay: 0.3s; }
.mini-bar:nth-child(4) { animation-delay: 0.4s; }
.mini-bar:nth-child(5) { animation-delay: 0.5s; }
.mini-bar:nth-child(6) { animation-delay: 0.6s; }
.mini-bar:nth-child(7) { animation-delay: 0.7s; }

@keyframes barGrow {
    from {
        height: 0;
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.scroll-indicator {
    position: absolute;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    color: var(--gray);
    font-size: 13px;
    font-weight: 500;
}

.scroll-arrow {
    width: 24px;
    height: 24px;
    border-right: 2px solid var(--gray);
    border-bottom: 2px solid var(--gray);
    transform: rotate(45deg);
    animation: scrollBounce 2s infinite;
}

@keyframes scrollBounce {
    0%, 100% { transform: rotate(45deg) translate(0, 0); }
    50% { transform: rotate(45deg) translate(4px, 4px); }
}

/* ===== 通用 Section 样式 ===== */
.section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    border-radius: 50px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 16px;
}

.section-title {
    font-size: 40px;
    font-weight: 800;
    color: var(--dark);
    margin-bottom: 12px;
}

.section-subtitle {
    font-size: 18px;
    color: var(--gray);
    max-width: 600px;
    margin: 0 auto;
}

/* ===== 关于我 ===== */
.about {
    background: var(--bg-white);
}

.about-content {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-text p {
    font-size: 16px;
    color: var(--gray);
    line-height: 1.9;
    margin-bottom: 20px;
}

.about-text strong {
    color: var(--dark);
    font-weight: 700;
}

.about-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 28px;
}

.tag {
    padding: 8px 16px;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    color: var(--dark-light);
    transition: all 0.2s ease;
}

.tag:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: rgba(37, 99, 235, 0.05);
}

.about-image {
    display: flex;
    justify-content: center;
}

.image-frame {
    position: relative;
    width: 320px;
    height: 320px;
}

.data-avatar {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 200px;
    height: 200px;
}

.avatar-ring {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    border: 4px dashed var(--primary);
    border-radius: 50%;
    animation: rotate 20s linear infinite;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.avatar-inner {
    position: absolute;
    top: 15px;
    left: 15px;
    right: 15px;
    bottom: 15px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 20px 40px rgba(37, 99, 235, 0.3);
}

.avatar-icon {
    font-size: 72px;
}

.floating-card {
    position: absolute;
    background: white;
    padding: 12px 20px;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    gap: 2px;
    animation: cardFloat 4s ease-in-out infinite;
}

.card-top {
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    animation-delay: 0s;
}

.card-right {
    top: 50%;
    right: 0;
    transform: translateY(-50%);
    animation-delay: 1.3s;
}

.card-bottom {
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    animation-delay: 2.6s;
}

@keyframes cardFloat {
    0%, 100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(-10px); }
}

.card-right {
    animation-name: cardFloatRight;
}

@keyframes cardFloatRight {
    0%, 100% { transform: translateY(-50%) translateX(0); }
    50% { transform: translateY(-50%) translateX(-10px); }
}

.card-label {
    font-size: 12px;
    color: var(--gray);
    font-weight: 500;
}

.card-value {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary);
}

/* ===== 技能 ===== */
.skills {
    background: var(--bg);
}

.skills-content {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 60px;
    align-items: center;
    margin-bottom: 64px;
}

.skills-chart {
    display: flex;
    justify-content: center;
}

.radar-img {
    width: 100%;
    max-width: 400px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.skill-category {
    margin-bottom: 32px;
}

.skill-category:last-child {
    margin-bottom: 0;
}

.skill-category h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 16px;
}

.skill-items {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.skill-item {
    display: grid;
    grid-template-columns: 140px 1fr 50px;
    gap: 16px;
    align-items: center;
}

.skill-name {
    font-size: 15px;
    font-weight: 500;
    color: var(--dark-light);
}

.skill-bar {
    height: 10px;
    background: var(--gray-lighter);
    border-radius: 5px;
    overflow: hidden;
}

.skill-progress {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 5px;
    transition: width 1s ease-out;
}

.skill-percent {
    font-size: 14px;
    font-weight: 700;
    color: var(--primary);
    text-align: right;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.tool-card {
    background: white;
    padding: 24px;
    border-radius: 16px;
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid var(--border);
}

.tool-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.tool-icon {
    font-size: 40px;
    margin-bottom: 12px;
}

.tool-name {
    font-size: 16px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 4px;
}

.tool-desc {
    font-size: 13px;
    color: var(--gray);
}

/* ===== 项目 ===== */
.projects {
    background: var(--bg-white);
}

.project-overview {
    margin-bottom: 64px;
    text-align: center;
}

.overview-img {
    max-width: 900px;
    width: 100%;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.project-card {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: center;
    background: var(--bg);
    border-radius: 24px;
    padding: 48px;
    margin-bottom: 32px;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
}

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

.project-card.reverse .project-info {
    order: 2;
}

.project-card.reverse .project-visual {
    order: 1;
}

.project-badge {
    display: inline-block;
    padding: 6px 14px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 16px;
}

.project-title {
    font-size: 28px;
    font-weight: 800;
    color: var(--dark);
    margin-bottom: 12px;
}

.project-meta {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
}

.meta-item {
    font-size: 14px;
    color: var(--gray);
    font-weight: 500;
}

.project-desc {
    font-size: 16px;
    color: var(--gray);
    line-height: 1.8;
    margin-bottom: 24px;
}

.project-highlights {
    display: flex;
    gap: 32px;
    margin-bottom: 24px;
}

.highlight-item {
    text-align: center;
}

.highlight-value {
    display: block;
    font-size: 28px;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.highlight-label {
    font-size: 13px;
    color: var(--gray);
    font-weight: 500;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tech-tag {
    padding: 6px 14px;
    background: white;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 13px;
    font-weight: 600;
    color: var(--dark-light);
}

.project-visual {
    position: relative;
}

.project-img {
    width: 100%;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.img-caption {
    text-align: center;
    font-size: 14px;
    color: var(--gray);
    margin-top: 12px;
    font-style: italic;
}

/* ===== 实习经验 ===== */
.internship {
    background: var(--bg);
}

.timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--gray-lighter);
}

.timeline-item {
    position: relative;
    padding-left: 60px;
    margin-bottom: 0;
}

.timeline-dot {
    position: absolute;
    left: 12px;
    top: 8px;
    width: 18px;
    height: 18px;
    background: var(--primary);
    border-radius: 50%;
    border: 4px solid white;
    box-shadow: 0 0 0 2px var(--primary);
}

.timeline-content {
    background: white;
    padding: 28px;
    border-radius: 16px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 8px;
    flex-wrap: wrap;
    gap: 8px;
}

.timeline-header h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--dark);
}

.timeline-date {
    font-size: 14px;
    color: var(--primary);
    font-weight: 600;
    background: rgba(37, 99, 235, 0.1);
    padding: 4px 12px;
    border-radius: 8px;
}

.timeline-company {
    font-size: 15px;
    color: var(--gray);
    font-weight: 500;
    margin-bottom: 16px;
}

.timeline-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.timeline-list li {
    position: relative;
    padding-left: 20px;
    font-size: 15px;
    color: var(--gray);
    line-height: 1.7;
}

.timeline-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--accent);
    font-weight: 700;
}

.timeline-list strong {
    color: var(--primary);
    font-weight: 700;
}

/* ===== 教育背景 ===== */
.education {
    background: var(--bg-white);
}

.education-card {
    max-width: 800px;
    margin: 0 auto;
    background: var(--bg);
    border-radius: 24px;
    padding: 40px;
    border: 1px solid var(--border);
}

.edu-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 28px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 28px;
    flex-wrap: wrap;
    gap: 16px;
}

.edu-school {
    display: flex;
    align-items: center;
    gap: 16px;
}

.edu-logo {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
}

.edu-info h3 {
    font-size: 24px;
    font-weight: 800;
    color: var(--dark);
    margin-bottom: 4px;
}

.edu-info p {
    font-size: 15px;
    color: var(--gray);
}

.edu-gpa {
    text-align: center;
    background: white;
    padding: 12px 24px;
    border-radius: 12px;
    border: 1px solid var(--border);
}

.gpa-label {
    display: block;
    font-size: 12px;
    color: var(--gray);
    font-weight: 500;
    margin-bottom: 2px;
}

.gpa-value {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
}

.edu-body {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.edu-section h4 {
    font-size: 16px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 12px;
}

.edu-section p {
    font-size: 15px;
    color: var(--gray);
}

.edu-section strong {
    color: var(--primary);
    font-weight: 700;
}

.course-tags {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.course-tag {
    padding: 6px 12px;
    background: white;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 13px;
    font-weight: 500;
    color: var(--dark-light);
    text-align: center;
}

.cert-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.cert-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    color: var(--dark-light);
    font-weight: 500;
}

.cert-icon {
    font-size: 18px;
}

/* ===== 联系方式 ===== */
.contact {
    background: var(--bg);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    max-width: 900px;
    margin: 0 auto;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 20px;
    background: white;
    border-radius: 16px;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
}

.contact-item:hover {
    border-color: var(--primary);
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    width: 52px;
    height: 52px;
    background: rgba(37, 99, 235, 0.1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    flex-shrink: 0;
}

.contact-text {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.contact-label {
    font-size: 13px;
    color: var(--gray);
    font-weight: 500;
}

.contact-value {
    font-size: 16px;
    font-weight: 600;
    color: var(--dark);
    text-decoration: none;
    transition: color 0.2s ease;
}

a.contact-value:hover {
    color: var(--primary);
}

.contact-cta {
    display: flex;
    align-items: center;
}

.cta-card {
    background: var(--gradient-primary);
    padding: 40px;
    border-radius: 24px;
    color: white;
    text-align: center;
    width: 100%;
}

.cta-card h3 {
    font-size: 28px;
    font-weight: 800;
    margin-bottom: 12px;
}

.cta-card p {
    font-size: 16px;
    opacity: 0.9;
    margin-bottom: 28px;
    line-height: 1.7;
}

.cta-card .btn-primary {
    background: white;
    color: var(--primary);
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
}

.cta-card .btn-primary:hover {
    background: #f8fafc;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}

/* ===== 页脚 ===== */
.footer {
    background: var(--dark);
    color: white;
    padding: 48px 0 24px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 32px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    flex-wrap: wrap;
    gap: 24px;
}

.footer-left {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 20px;
}

.footer-desc {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
}

.footer-right {
    display: flex;
    gap: 16px;
}

.footer-link {
    width: 44px;
    height: 44px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    transition: all 0.3s ease;
}

.footer-link:hover {
    background: var(--primary);
    transform: translateY(-2px);
}

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    font-size: 14px;
    color: rgba(255, 255, 255, 0.5);
}

/* ===== 回到顶部 ===== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.3s ease;
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 25px rgba(37, 99, 235, 0.4);
}

/* ===== 响应式设计 ===== */
@media (max-width: 1024px) {
    .hero-title {
        font-size: 48px;
    }
    
    .section-title {
        font-size: 36px;
    }
    
    .tools-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .project-card {
        padding: 36px;
        gap: 36px;
    }
    
    .project-title {
        font-size: 24px;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 16px;
        gap: 4px;
        box-shadow: var(--shadow-lg);
        border-top: 1px solid var(--border);
    }
    
    .nav-menu.active {
        display: flex;
    }
    
    .hamburger {
        display: flex;
    }
    
    .hamburger.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }
    
    .hamburger.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }
    
    .hero {
        min-height: auto;
        padding: 120px 0 80px;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        gap: 48px;
        text-align: center;
    }
    
    .hero-title {
        font-size: 40px;
    }
    
    .hero-subtitle {
        font-size: 20px;
    }
    
    .hero-description {
        margin: 0 auto 32px;
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
        max-width: 400px;
        margin: 0 auto;
    }
    
    .stat-item {
        text-align: center;
    }
    
    .hero-visual {
        order: -1;
    }
    
    .section {
        padding: 72px 0;
    }
    
    .section-title {
        font-size: 32px;
    }
    
    .about-content {
        grid-template-columns: 1fr;
        gap: 48px;
    }
    
    .skills-content {
        grid-template-columns: 1fr;
        gap: 48px;
    }
    
    .skill-item {
        grid-template-columns: 100px 1fr 40px;
        gap: 12px;
    }
    
    .tools-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .project-card {
        grid-template-columns: 1fr;
        padding: 28px;
        gap: 28px;
    }
    
    .project-card.reverse .project-info {
        order: 1;
    }
    
    .project-card.reverse .project-visual {
        order: 2;
    }
    
    .project-title {
        font-size: 22px;
    }
    
    .project-highlights {
        gap: 20px;
    }
    
    .highlight-value {
        font-size: 24px;
    }
    
    .edu-body {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    
    .cta-card {
        padding: 32px;
    }
    
    .cta-card h3 {
        font-size: 24px;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 32px;
    }
    
    .hero-subtitle {
        font-size: 18px;
    }
    
    .hero-buttons {
        flex-direction: column;
    }
    
    .btn {
        justify-content: center;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .tools-grid {
        grid-template-columns: 1fr;
    }
    
    .project-highlights {
        flex-direction: column;
        gap: 16px;
    }
    
    .timeline-header {
        flex-direction: column;
    }
    
    .edu-header {
        flex-direction: column;
        align-items: flex-start;
    }
}