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

body {
    font-family: 'Proxima Nova', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #002E5D 0%, #1B4F8C 50%, #2E5A88 100%);
    color: #333;
    line-height: 1.6;
    min-height: 100vh;
    padding-top: 70px; /* 为固定导航栏留出空间 */
}

/* 固定顶部导航栏 */
.top-navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(0, 46, 93, 0.98);
    backdrop-filter: blur(30px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.15);
    z-index: 1000;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.12);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
}

.nav-title {
    font-family: 'Freight Text', Georgia, serif;
    font-size: 1.2rem;
    font-weight: 600;
    color: #FFFFFF;
    white-space: nowrap;
    text-decoration: none;
    transition: color 0.3s ease;
}

.nav-title:hover {
    color: #FFC107;
}

.nav-left {
    display: flex;
    align-items: center;
}

.nav-center {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-menu {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-link {
    color: #E8F4FD;
    text-decoration: none;
    font-family: 'Proxima Nova', sans-serif;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
    padding: 8px 0;
}

.nav-link:hover {
    color: #FFC107;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: #FFC107;
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    padding-top: 20px; /* 减少顶部间距 */
}

.header {
    text-align: center;
    margin-bottom: 30px;
    padding: 40px 0 40px 0;
    color: white;
}

.main-title {
    font-family: 'Freight Text', Georgia, serif;
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
    animation: fadeInUp 1s ease-out;
    color: #FFFFFF;
}

.header p {
    font-family: 'Proxima Nova', sans-serif;
    font-size: 1.3rem;
    opacity: 0.95;
    max-width: 600px;
    margin: 0 auto;
    animation: fadeInUp 1s ease-out 0.2s both;
    color: #E8F4FD;
}

.main-content {
    display: flex;
    flex-direction: column;
    gap: 30px;
    margin-top: 30px;
    margin-bottom: 60px;
}

.upload-section {
    background: rgba(255, 255, 255, 0.98);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
    backdrop-filter: blur(10px);
    animation: slideInLeft 1s ease-out;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.upload-area {
    border: 3px dashed #002E5D;
    border-radius: 12px;
    padding: 60px 20px;
    text-align: center;
    background: linear-gradient(135deg, #F8FBFF 0%, #E8F4FD 100%);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    margin-bottom: 30px;
    position: relative;
    overflow: hidden;
}

.upload-area::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.4), transparent);
    transition: left 0.5s;
}

.upload-area:hover::before {
    left: 100%;
}

.upload-area:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 46, 93, 0.2);
    border-color: #1B4F8C;
}

.upload-area.dragover {
    background: linear-gradient(135deg, #E8F4FD 0%, #D1E9FB 100%);
    border-color: #1B4F8C;
    transform: scale(1.02);
}

.upload-icon {
    font-size: 4rem;
    color: #002E5D;
    margin-bottom: 20px;
    animation: bounce 2s infinite;
}

.upload-text {
    font-size: 1.4rem;
    color: #002E5D;
    margin-bottom: 15px;
    font-weight: 600;
    font-family: 'Proxima Nova', sans-serif;
}

.upload-hint {
    font-size: 1rem;
    color: #666;
    font-family: 'Proxima Nova', sans-serif;
}

.file-input {
    display: none;
}

.btn {
    background: #002E5D;
    color: white;
    border: none;
    padding: 15px 40px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: 8px;
    font-family: 'Proxima Nova', sans-serif;
}

.btn:hover {
    background: #1B4F8C;
    transform: translateY(-2px);
}

.btn:active {
    transform: translateY(0);
}

.btn:disabled {
    background: #ccc;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.progress-container {
    display: none;
    margin: 30px 0;
}

.progress-bar {
    width: 100%;
    height: 12px;
    background: #E8F4FD;
    border-radius: 6px;
    overflow: hidden;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.1);
}

.progress-fill {
    height: 100%;
    background: #002E5D;
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 6px;
}

.status-message {
    margin-top: 20px;
    padding: 20px;
    border-radius: 8px;
    display: none;
    font-weight: 500;
    font-family: 'Proxima Nova', sans-serif;
}

.status-success {
    background: linear-gradient(135deg, #E8F5E8 0%, #D4EDDA 100%);
    color: #155724;
    border: 1px solid #C3E6CB;
}

.status-error {
    background: linear-gradient(135deg, #F8D7DA 0%, #F5C6CB 100%);
    color: #721C24;
    border: 1px solid #F5C6CB;
}

.info-section {
    background: rgba(255, 255, 255, 0.98);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
    backdrop-filter: blur(10px);
    animation: slideInRight 1s ease-out;
    border: 1px solid rgba(255, 255, 255, 0.2);
    text-align: center;
}

.info-icon {
    font-size: 3rem;
    color: #002E5D;
    margin-bottom: 20px;
    text-align: center;
    animation: pulse 2s infinite;
}

.info-steps {
    margin-bottom: 30px;
    text-align: center;
}

.step {
    display: flex;
    align-items: flex-start;
    margin-bottom: 25px;
    padding: 15px;
    background: linear-gradient(135deg, #F8FBFF 0%, #E8F4FD 100%);
    border-radius: 8px;
    transition: all 0.3s ease;
    border: 1px solid rgba(0, 46, 93, 0.1);
}

.step:hover {
    transform: translateX(5px);
    box-shadow: 0 5px 15px rgba(0, 46, 93, 0.15);
}

.step-number {
    background: linear-gradient(135deg, #002E5D 0%, #1B4F8C 100%);
    color: white;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    margin-right: 15px;
    flex-shrink: 0;
    font-family: 'Proxima Nova', sans-serif;
}

.step-content {
    text-align: center;
    flex: 1;
}

.step-content h4 {
    color: #002E5D;
    margin-bottom: 5px;
    font-size: 1.1rem;
    font-weight: 600;
    font-family: 'Proxima Nova', sans-serif;
    text-align: center;
}

.step-content p {
    color: #666;
    font-size: 0.95rem;
    line-height: 1.5;
    font-family: 'Proxima Nova', sans-serif;
    text-align: center;
}

.download-section {
    display: none;
    background: rgba(255, 255, 255, 0.98);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
    backdrop-filter: blur(10px);
    text-align: center;
    animation: slideInRight 1s ease-out;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.download-icon {
    font-size: 3rem;
    color: #28A745;
    margin-bottom: 20px;
    animation: pulse 2s infinite;
}

.features-section {
    background: rgba(255, 255, 255, 0.98);
    padding: 60px 40px;
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
    backdrop-filter: blur(10px);
    animation: fadeInUp 1s ease-out 0.4s both;
    border: 1px solid rgba(255, 255, 255, 0.2);
    text-align: center;
}

.features {
    display: flex;
    flex-direction: column;
    gap: 20px;
    align-items: center;
    max-width: 800px;
    margin: 0 auto;
}

.feature {
    text-align: center;
    padding: 25px;
    border-radius: 8px;
    background: white;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid #e0e0e0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    max-width: 600px;
    width: 100%;
}

.feature:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 46, 93, 0.15);
}

.feature-icon {
    font-size: 2.5rem;
    color: #002E5D;
    margin-bottom: 15px;
    text-align: center;
}

.feature h3 {
    margin-bottom: 15px;
    color: #002E5D;
    font-size: 1.4rem;
    font-weight: 600;
    font-family: 'Proxima Nova', sans-serif;
    text-align: center;
}

.feature p {
    color: #666;
    line-height: 1.6;
    font-family: 'Proxima Nova', sans-serif;
    text-align: center;
}

.footer {
    text-align: center;
    margin-top: 80px;
    padding: 40px;
    color: rgba(255, 255, 255, 0.9);
    font-family: 'Proxima Nova', sans-serif;
}

/* UC Davis Brand Colors */
:root {
    --ucdavis-blue: #002E5D;
    --ucdavis-blue-light: #1B4F8C;
    --ucdavis-blue-lighter: #2E5A88;
    --ucdavis-gold: #FFC107;
    --ucdavis-white: #FFFFFF;
    --ucdavis-light-blue: #E8F4FD;
    --ucdavis-lighter-blue: #F8FBFF;
}

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

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

@keyframes pulse {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
    }
    100% {
        transform: scale(1);
    }
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%);
    }
    100% {
        transform: translateX(100%);
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 15px;
        padding-top: 15px;
    }

    .nav-container {
        height: 60px;
        padding: 0 15px;
    }

    .nav-title {
        font-size: 1rem;
    }

    .nav-left {
        display: flex;
        align-items: center;
    }

    .nav-center {
        gap: 20px;
    }

    .nav-menu {
        gap: 20px;
    }

    .nav-link {
        font-size: 0.85rem;
    }

    .main-title {
        font-size: 2rem;
    }


    
    .main-content {
        gap: 20px;
    }
    
    .upload-section {
        padding: 25px 20px;
    }
    
    .upload-area {
        padding: 40px 20px;
    }
    
    .download-section {
        padding: 25px 20px;
    }
    
    .features-section {
        padding: 0 10px;
    }
    
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
}

@media (max-width: 480px) {
    .nav-container {
        height: 55px;
        padding: 0 10px;
    }

    .nav-title {
        font-size: 0.9rem;
    }

    .nav-left {
        display: flex;
        align-items: center;
    }

    .nav-center {
        gap: 15px;
    }

    .nav-menu {
        gap: 15px;
    }

    .nav-link {
        font-size: 0.8rem;
    }

    .main-title {
        font-size: 1.8rem;
    }


    
    .upload-area {
        padding: 30px 15px;
    }
    
    .btn {
        padding: 12px 20px;
        font-size: 0.9rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 15px;
    }
}

/* Footer Styles */
.footer {
    background: #002E5D;
    color: white;
    padding: 40px 0 20px 0;
    margin-top: 60px;
    border-radius: 12px 12px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    margin-bottom: 30px;
    padding: 0 30px;
}

.footer-section h4 {
    color: #FFBF00;
    font-family: 'Proxima Nova', sans-serif;
    font-size: 1.1rem;
    font-weight: 600;
    margin: 0 0 15px 0;
    border-bottom: 2px solid #FFBF00;
    padding-bottom: 8px;
    display: inline-block;
}

.footer-section p {
    color: #E0E0E0;
    font-family: 'Proxima Nova', sans-serif;
    font-size: 0.9rem;
    line-height: 1.6;
    margin: 0 0 10px 0;
}

.footer-section a {
    color: #FFBF00;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: #FFCC33;
    text-decoration: underline;
}

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

.footer-section ul li {
    color: #E0E0E0;
    font-family: 'Proxima Nova', sans-serif;
    font-size: 0.9rem;
    margin-bottom: 8px;
    padding-left: 15px;
    position: relative;
}

.footer-section ul li:before {
    content: "•";
    color: #FFBF00;
    position: absolute;
    left: 0;
    font-weight: bold;
}

.footer-bottom {
    border-top: 1px solid #0047BA;
    padding-top: 20px;
    text-align: center;
    padding: 20px 30px 0 30px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.footer-bottom p {
    color: #B0B0B0;
    font-family: 'Proxima Nova', sans-serif;
    font-size: 0.8rem;
    margin: 5px 0;
    line-height: 1.5;
    text-align: center;
    width: 100%;
}

.footer-bottom a {
    color: #FFBF00;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-bottom a:hover {
    color: #FFCC33;
    text-decoration: underline;
}