:root {
    --primary-color: #4a90e2;
    --secondary-color: #2c3e50;
    --accent-color: #e74c3c;
    --background-color: #f8f9fa;
    --text-color: #333;
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f6f7fb;
    color: #222;
    margin: 0;
}

.header {
    background: #fff;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    padding: 0;
    position: sticky;
    top: 0;
    z-index: 10;
}

.nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.2rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 0.7rem;
}
.logo-img {
    width: 40px;
    height: 40px;
}
.logo-text {
    font-size: 1.6rem;
    font-weight: 700;
    color: #2c3e50;
    letter-spacing: 1px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2rem;
}
.nav-links a, .nav-links span {
    color: #222;
    text-decoration: none;
    font-size: 1.05rem;
    font-weight: 500;
    transition: color 0.2s;
    cursor: pointer;
}
.nav-links a:hover, .nav-links span:hover {
    color: #4a90e2;
}

.main-centered {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 3.5rem;
}

.card-container {
    background: #fff;
    border-radius: 18px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.07);
    display: flex;
    max-width: 900px;
    width: 100%;
    margin: 2rem;
    padding: 2.5rem 2rem;
    gap: 2.5rem;
}

.card-left, .card-right {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.card-left {
    max-width: 380px;
    gap: 1.2rem;
}

.prompt-label {
    font-weight: 600;
    margin-bottom: 0.3rem;
}

.prompt-row {
    display: flex;
    gap: 0.5rem;
}

.prompt-input {
    flex: 1;
    padding: 0.7rem 1rem;
    border: 1.5px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    outline: none;
    transition: border 0.2s;
}
.prompt-input:focus {
    border-color: #4a90e2;
}

.enhance-btn {
    background: #f3f3f3;
    color: #888;
    border: none;
    border-radius: 8px;
    padding: 0 1.1rem;
    font-size: 1rem;
    cursor: not-allowed;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.upload-area {
    border: 2px dashed #d1d5db;
    border-radius: 10px;
    background: #fafbfc;
    padding: 2.2rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
    margin-bottom: 0.5rem;
}
.upload-area.dragging {
    border-color: #4a90e2;
    background: #eaf3fb;
}
.upload-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.7rem;
}
.upload-content svg {
    margin-bottom: 0.2rem;
}
.file-input {
    display: none;
}

.convert-btn {
    width: 100%;
    padding: 0.9rem 0;
    background: #d1d5db;
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: not-allowed;
    transition: background 0.2s;
    margin-top: 0.2rem;
}
.convert-btn:enabled {
    background: #4a90e2;
    cursor: pointer;
}

.card-right {
    align-items: center;
    justify-content: center;
    text-align: center;
    gap: 1.2rem;
}
.card-right h2 {
    font-size: 1.4rem;
    font-weight: 700;
    color: #222;
    margin-bottom: 0.5rem;
}
.card-right p {
    color: #666;
    font-size: 1.05rem;
    margin-bottom: 1.2rem;
}
.card-right svg {
    margin-top: 0.5rem;
}

@media (max-width: 900px) {
    .card-container {
        flex-direction: column;
        align-items: stretch;
        padding: 2rem 1rem;
        gap: 1.5rem;
    }
    .main-centered {
        padding-top: 2.5rem;
    }
}

@media (max-width: 600px) {
    .nav {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem 0.5rem;
    }
    .card-container {
        padding: 1.2rem 0.2rem;
    }
    .card-left {
        max-width: 100%;
    }
}

.hero {
    padding: 8rem 2rem 4rem;
    text-align: center;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--secondary-color);
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    color: #666;
}

.btn {
    display: inline-block;
    padding: 0.8rem 2rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    margin: 0.5rem;
}

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

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

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.upload-section {
    padding: 4rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.upload-container {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.preview-container {
    margin-top: 2rem;
    text-align: center;
}

.preview-image {
    max-width: 100%;
    max-height: 400px;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
}

.preview-controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.features {
    padding: 4rem 2rem;
    background-color: white;
}

.features h2 {
    text-align: center;
    margin-bottom: 3rem;
    color: var(--secondary-color);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.feature-card {
    padding: 2rem;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.15);
}

.feature-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.footer {
    background-color: var(--secondary-color);
    color: white;
    padding: 4rem 2rem 2rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
}

.footer-section a {
    color: white;
    text-decoration: none;
    display: block;
    margin-bottom: 0.5rem;
    transition: var(--transition);
}

.footer-section a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}