/* Custom Styles for Tian Zeqi Portfolio */
/* Tailwind CSS is loaded via script in index.html, so no @import needed here. */

:root {
    --primary-blue: #2563eb;
    --primary-blue-hover: #1d4ed8;
    --secondary-purple: #9333ea;
    --text-gray: #374151;
    --light-gray: #f9fafb;
    --border-gray: #e5e7eb;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-gray);
    background-color: var(--light-gray);
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Custom gradient backgrounds */
.gradient-bg {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.text-gradient {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Hover effects */
.hover-scale {
    transition: transform 0.3s ease;
}

.hover-scale:hover {
    transform: scale(1.05);
}

/* Navigation styles */
.nav-fixed {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    z-index: 40;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.nav-item {
    padding: 0.5rem 0.75rem;
    border-radius: 0.375rem;
    font-weight: 500;
    transition: all 0.2s ease;
}

.nav-item:hover {
    color: var(--primary-blue);
}

.nav-item.active {
    background-color: rgba(37, 99, 235, 0.1);
    color: var(--primary-blue);
}

/* Button styles */
.primary-button { /* Renamed from .btn-primary for clarity with the toggle button */
    background-color: var(--primary-blue);
    color: white;
    padding: 0.75rem 2rem;
    border-radius: 0.5rem;
    font-weight: 500;
    transition: background-color 0.2s ease;
    border: none;
    cursor: pointer;
}

.primary-button:hover {
    background-color: var(--primary-blue-hover);
}

.btn-secondary {
    border: 2px solid var(--primary-blue);
    color: var(--primary-blue);
    background: transparent;
    padding: 0.75rem 2rem;
    border-radius: 0.5rem;
    font-weight: 500;
    transition: all 0.2s ease;
    cursor: pointer;
}

.btn-secondary:hover {
    background-color: rgba(37, 99, 235, 0.05);
}

/* Section styles */
.section {
    padding: 5rem 0;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 1rem;
    color: #1f2937;
}

.section-divider {
    width: 6rem;
    height: 0.25rem;
    background-color: var(--primary-blue);
    margin: 0 auto 4rem;
}

/* Hero section */
.hero {
    background: linear-gradient(135deg, #dbeafe 0%, #e0e7ff 100%);
    padding: 5rem 0 4rem;
    margin-top: 4rem;
}

.hero-title {
    font-size: clamp(2rem, 5vw, 3.75rem);
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: clamp(1.5rem, 3vw, 2.25rem);
    color: var(--primary-blue);
    margin-bottom: 1.5rem;
}

.hero-description {
    font-size: 1.25rem;
    color: #6b7280;
    margin-bottom: 2rem;
    line-height: 1.6;
}

/* About section */
.about-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    margin-top: 2rem;
}

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

.stat-number {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.stat-number.blue {
    color: var(--primary-blue);
}

.stat-number.purple {
    color: var(--secondary-purple);
}

/* Experience cards */
.experience-card {
    background: white;
    padding: 1.5rem;
    border-radius: 0.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    transition: box-shadow 0.2s ease;
    margin-bottom: 2rem;
}

.experience-card:hover {
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.experience-icon {
    width: 3rem;
    height: 3rem;
    background-color: rgba(37, 99, 235, 0.1);
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 1rem;
    flex-shrink: 0;
}

.experience-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.experience-role {
    color: var(--primary-blue);
    font-weight: 500;
    margin-bottom: 0.5rem;
}

/* Services grid */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.service-card {
    background: #f9fafb;
    padding: 1.5rem;
    border-radius: 0.5rem;
    transition: box-shadow 0.2s ease;
}

.service-card:hover {
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.service-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.service-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

/* Philosophy section */
.philosophy {
    background: #1f2937;
    color: white;
}

.philosophy-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
}

.philosophy-card {
    background: #374151;
    padding: 1.5rem;
    border-radius: 0.5rem;
}

.philosophy-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #60a5fa;
    margin-bottom: 0.75rem;
}

.philosophy-description {
    color: #d1d5db;
    margin-bottom: 1rem;
}

.philosophy-subtitle {
    font-size: 0.875rem;
    color: #9ca3af;
    font-style: italic;
}

/* Contact section */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 3rem;
}

.contact-item {
    margin-bottom: 2rem;
}

.contact-title {
    font-size: 1.125rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    margin-bottom: 1rem;
}

.contact-icon {
    width: 1.25rem;
    height: 1.25rem;
    color: var(--primary-blue);
    margin-right: 0.5rem;
}

.contact-content {
    margin-left: 1.75rem;
}

.contact-text {
    color: #6b7280;
    margin-bottom: 0.5rem;
}

/* Social media icons */
.social-icons {
    display: flex;
    gap: 1rem;
    margin-left: 1.75rem;
}

.social-icon {
    width: 1.5rem;
    height: 1.5rem;
    fill: currentColor;
    transition: transform 0.2s ease;
}

.social-icon:hover {
    transform: scale(1.1);
}

.social-link {
    transition: color 0.2s ease;
}

.social-link.wechat {
    color: #07c160;
}

.social-link.wechat:hover {
    color: #06ad56;
}

.social-link.whatsapp {
    color: #25d366;
}

.social-link.whatsapp:hover {
    color: #20ba5a;
}

.social-link.telegram {
    color: #0088cc;
}

.social-link.telegram:hover {
    color: #006ba6;
}

/* Form styles */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: #374151;
    margin-bottom: 0.5rem;
}

.form-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-gray);
    border-radius: 0.5rem;
    font-size: 1rem;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
}

/* Footer */
.footer {
    background: #1f2937;
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer-text {
    color: #9ca3af;
}

/* Responsive design */
@media (max-width: 992px) { /* Adjusted for consistency */
    .hero {
        padding: 3rem 0 2rem;
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .hero-subtitle {
        font-size: 1.8rem; /* Adjusted */
    }
    
    .hero-description {
        font-size: 1.125rem;
    }
    
    .section {
        padding: 3rem 0;
    }
    
    .section-title {
        font-size: 2.25rem;
    }
    
    .about-stats {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .services-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); /* Adjusted */
    }
    
    .philosophy-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
    }
}


@media (max-width: 768px) {
    .hero {
        padding: 3rem 0 2rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.5rem;
    }
    
    .hero-description {
        font-size: 1.125rem;
    }
    
    .section {
        padding: 3rem 0;
    }
    
    .section-title {
        font-size: 1.875rem;
    }
    
    /* Mobile menu specific styles */
    .header-nav {
        display: none; /* Hide desktop nav */
    }
    .header-container {
        flex-wrap: wrap;
    }
    #mobile-menu-button {
        display: block; /* Show mobile menu button */
    }
    #mobile-menu.hidden {
        display: none;
    }
    #mobile-menu:not(.hidden) {
        display: block;
    }


    .about-stats {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
    }
    
    .philosophy-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }
    
    .btn-primary,
    .btn-secondary {
        padding: 0.625rem 1.5rem;
        font-size: 0.875rem;
    }
    
    .experience-card {
        padding: 1rem;
    }
    
    .service-card,
    .philosophy-card {
        padding: 1rem;
    }
}

/* Animation keyframes (kept from previous version) */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Animation classes */
.animate-fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}

.animate-fade-in-left {
    animation: fadeInLeft 0.6s ease-out;
}

.animate-fade-in-right {
    animation: fadeInRight 0.6s ease-out;
}

/* Utility classes (from previous version, some might be redundant with Tailwind but kept for specific custom classes if they exist) */
.container {
    max-width: 80rem;
    margin: 0 auto;
    padding: 0 1.5rem;
}

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

.mb-4 {
    margin-bottom: 1rem;
}

.mb-8 {
    margin-bottom: 2rem;
}

.mb-16 {
    margin-bottom: 4rem;
}

.mt-4 {
    margin-top: 1rem;
}

.mt-8 {
    margin-top: 2rem;
}

.p-4 {
    padding: 1rem;
}

.p-6 {
    padding: 1.5rem;
}

.rounded-lg {
    border-radius: 0.5rem;
}

.rounded-xl {
    border-radius: 0.75rem;
}

.rounded-2xl {
    border-radius: 1rem;
}

.shadow-md {
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.shadow-lg {
    box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
}

.shadow-xl {
    box-shadow: 0 20px 25px rgba(0, 0, 0, 0.1);
}

.shadow-2xl {
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.25);
}