/* 
==============================================
AI探索之旅 - 全局样式
==============================================
*/

:root {
    --primary-color: #007aff;
    --background-dark: #000000;
    --surface-dark: #151516;
    --text-color-primary: #f5f5f7;
    --text-color-secondary: #a1a1a6;
    --border-color: #3a3a3c;
    --font-family-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
    --border-radius: 20px;
    --transition-speed: 0.4s;
}

/* 
==============================================
基础重置与全局设置
==============================================
*/

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

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

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color var(--transition-speed) ease;
}

a:hover {
    filter: brightness(1.2);
}

img,
canvas {
    max-width: 100%;
    display: block;
}

/* 
==============================================
布局与容器
==============================================
*/

.section-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 6rem 2rem;
    text-align: center;
}

/* 
==============================================
头部导航
==============================================
*/

.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: transparent;
    transition: background-color var(--transition-speed) ease, backdrop-filter var(--transition-speed) ease;
}

.site-header.scrolled {
    background-color: rgba(22, 22, 23, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
}

.main-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1400px;
    margin: 0 auto;
    padding: 1.5rem 2.5rem;
    transition: padding var(--transition-speed) ease;
}

.site-header.scrolled .main-nav {
    padding: 1rem 2.5rem;
}

.logo a {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-color-primary);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2.5rem;
}

.nav-links a {
    color: var(--text-color-secondary);
    font-weight: 500;
    transition: color var(--transition-speed) ease;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-color-primary);
}


/* 
==============================================
Hero区域
==============================================
*/

.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero-content {
    z-index: 2;
    position: relative;
}

.main-title {
    font-size: 5rem;
    font-weight: 700;
    letter-spacing: -2px;
    margin-bottom: 1rem;
    color: var(--text-color-primary);
}

.subtitle {
    font-size: 1.8rem;
    font-weight: 300;
    color: var(--text-color-secondary);
    margin-bottom: 3rem;
}

.cta-button {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 2.5rem;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 500;
    transition: transform var(--transition-speed) ease, background-color var(--transition-speed) ease;
}

.cta-button:hover {
    transform: scale(1.05);
    background-color: #0088ff;
    color: white;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    background: #000;
}

#hero-canvas {
    width: 100%;
    height: 100%;
    opacity: 0.6;
}

/* 
==============================================
内容区域
==============================================
*/

.content-section {
    padding: 6rem 2rem;
    background-color: var(--background-dark);
    color: var(--text-color-primary);
    border-bottom: 1px solid var(--border-color);
}

.content-section:last-of-type {
    border-bottom: none;
}

.section-title {
    font-size: 4rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.section-intro {
    font-size: 1.5rem;
    color: var(--text-color-secondary);
    max-width: 800px;
    margin: 0 auto 5rem;
    line-height: 1.8;
}

/* Intro Section */
#intro .section-container {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.typing-effect {
    font-size: 1.8rem;
    font-weight: 500;
    background: linear-gradient(90deg, var(--primary-color), #8e86ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    padding: 2rem;
    border-radius: var(--border-radius);
    margin-top: 3rem;
}


/* Principles Section */
.workflow-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 4rem;
    text-align: center;
}

.workflow-step {
    padding: 2rem 0;
}

.step-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.step-title {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--text-color-primary);
}

.workflow-step p {
    font-size: 1.1rem;
    color: var(--text-color-secondary);
    max-width: 300px;
    margin: 0 auto;
}

/* Challenges Section */
.challenges-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 5rem;
    max-width: 900px;
    margin: 0 auto;
    text-align: left;
}

.challenge-item {
    display: flex;
    align-items: flex-start;
    gap: 2.5rem;
}

.challenge-icon {
    font-size: 2.2rem; /* Slightly adjust size for consistency */
    color: var(--primary-color);
    min-width: 50px;
    padding-top: 5px; /* Align icon better with text */
    text-align: center;
}

.challenge-item h3 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.challenge-item p {
    color: var(--text-color-secondary);
    font-size: 1.1rem;
}

/* Future Section */
.future-vision-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 4rem;
    text-align: center;
}

.vision-item {
    padding: 2rem;
}

.vision-item i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.vision-item h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--text-color-primary);
}

.vision-item p {
    color: var(--text-color-secondary);
    font-size: 1.1rem;
}

/* About Section */
.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 4rem;
    text-align: center;
    margin-top: 5rem;
}

.about-item {
    padding: 2rem;
}

.about-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.about-item h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--text-color-primary);
}

.about-item p {
    color: var(--text-color-secondary);
    font-size: 1.1rem;
    text-align: left;
}


/* 
==============================================
页脚
==============================================
*/

.site-footer {
    background-color: var(--surface-dark);
    color: var(--text-color-secondary);
    padding: 5rem 2rem 2rem;
    text-align: left;
    border-top: 1px solid var(--border-color);
}

.footer-content-container {
    max-width: 1200px;
    margin: 0 auto;
}

.footer-main {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 3rem;
    padding-bottom: 3rem;
    margin-bottom: 3rem;
    border-bottom: 1px solid var(--border-color);
}

.footer-column h4 {
    font-size: 1.1rem;
    color: var(--text-color-primary);
    margin-bottom: 1.5rem;
}

.footer-column ul {
    list-style: none;
    padding: 0;
}

.footer-column li {
    margin-bottom: 1rem;
}

.footer-column a {
    color: var(--text-color-secondary);
    font-size: 0.95rem;
}

.footer-column a:hover {
    color: var(--text-color-primary);
    filter: none; /* Override general hover effect */
}

.footer-column .fab,
.footer-column .fas {
    display: inline-block;
    width: 1.2em; /* Ensure icons occupy the same space */
    text-align: center;
    margin-right: 0.5rem;
}

.project-info p {
    font-size: 0.95rem;
    line-height: 1.6;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.9rem;
}

.footer-legal a {
    margin-left: 1.5rem;
    color: var(--text-color-secondary);
}

/* 
==============================================
响应式设计
==============================================
*/
@media (max-width: 992px) {
    .section-title {
        font-size: 3rem;
    }
    .section-intro {
        font-size: 1.2rem;
    }
}
@media (max-width: 768px) {
    .main-title {
        font-size: 3.5rem;
    }
    .subtitle {
        font-size: 1.5rem;
    }
    .section-title {
        font-size: 2.5rem;
    }
    .main-nav {
        flex-direction: column;
        gap: 1.5rem;
        padding: 1rem 1.5rem;
    }
    .nav-links {
        gap: 1rem;
        font-size: 0.9rem;
    }
    .workflow-container,
    .future-vision-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }
    .challenge-item {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 1.5rem;
    }
    .footer-main {
        grid-template-columns: 1fr 1fr; /* Two columns on tablets */
    }
    .footer-bottom {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
}

@media (max-width: 480px) {
    .footer-main {
        grid-template-columns: 1fr; /* Single column on mobile */
    }
}