:root {
    --primary-color: #1a9837;
    --secondary-color: #f8f9fa;
    --accent-color: #1a9837;
    --dark-color: #343a40;
    --light-color: #ffffff;
    --border-radius: 8px;
    --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--secondary-color);
    color: var(--dark-color);
    line-height: 1.6;
}

header {
    background-color: var(--light-color);
    box-shadow: var(--box-shadow);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.logo span {
    color: var(--accent-color);
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--dark-color);
    font-weight: 500;
    transition: var(--transition);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
}

.nav-links a:hover {
    color: var(--primary-color);
    background-color: rgba(74, 107, 255, 0.1);
}

.nav-links a.active {
    color: var(--light-color);
    background-color: var(--primary-color);
}

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

.hero {
    text-align: center;
    margin-bottom: 3rem;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--dark-color);
}

.hero p {
    font-size: 1.1rem;
    color: #666;
    max-width: 700px;
    margin: 0 auto 2rem;
}

.tool-section {
    background-color: var(--light-color);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 2rem;
    margin-bottom: 3rem;
}

.tool-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.tool-header h2 {
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.file-upload {
    border: 2px dashed #ccc;
    border-radius: var(--border-radius);
    padding: 3rem 2rem;
    text-align: center;
    margin-bottom: 2rem;
    position: relative;
    transition: var(--transition);
    cursor: pointer;
}

.file-upload.small {
    padding: 1.5rem;
}

.file-upload:hover {
    border-color: var(--primary-color);
}

.file-upload input {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    opacity: 0;
    cursor: pointer;
}

.file-upload i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.file-upload.small i {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.file-upload h3 {
    margin-bottom: 0.5rem;
}

.file-upload p {
    color: #666;
    font-size: 0.9rem;
}

.preview-container {
    background-color: var(--secondary-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 2rem;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.preview-header h3 {
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.preview-content {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
}

.original-preview, .watermarked-preview {
    flex: 1;
    min-width: 300px;
}

.original-preview h4, .watermarked-preview h4 {
    margin-bottom: 1rem;
    color: var(--dark-color);
}

.original-preview img, .watermarked-preview canvas {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    background-color: #f0f0f0;
    display: block;
    margin-bottom: 1rem;
}

.preview-actions {
    display: flex;
    justify-content: center;
}

.options-section {
    margin-bottom: 2rem;
    background-color: var(--secondary-color);
    padding: 1.5rem;
    border-radius: var(--border-radius);
}

.options-section h3 {
    margin-bottom: 1rem;
    color: var(--dark-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.option-tabs {
    display: flex;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid #ddd;
}

.option-tab {
    padding: 0.7rem 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    font-weight: 500;
    color: #666;
    border-bottom: 3px solid transparent;
    transition: var(--transition);
}

.option-tab.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.option-group {
    margin-bottom: 1.5rem;
}

.option-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.option-group input[type="text"],
.option-group input[type="color"],
.option-group select {
    width: 100%;
    padding: 0.7rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.option-group input[type="text"]:focus,
.option-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(74, 107, 255, 0.2);
}

.option-group input[type="range"] {
    width: 100%;
    padding: 0;
}

.range-value {
    display: inline-block;
    margin-left: 0.5rem;
    font-weight: 500;
}

.position-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.5rem;
}

.position-btn {
    padding: 0.5rem;
    background-color: var(--light-color);
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
}

.position-btn:hover {
    background-color: var(--secondary-color);
}

.position-btn.active {
    background-color: var(--primary-color);
    color: var(--light-color);
    border-color: var(--primary-color);
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.checkbox-group input {
    width: auto;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background-color: var(--primary-color);
    color: var(--light-color);
    padding: 0.7rem 1.5rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    gap: 0.5rem;
}

.btn:hover {
    background-color: var(--accent-color);
}

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

.btn-outline:hover {
    background-color: var(--primary-color);
    color: var(--light-color);
}

.about-section {
    background-color: var(--light-color);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 2rem;
    margin-bottom: 2rem;
}

.about-section h2 {
    margin-bottom: 1rem;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.about-section p {
    margin-bottom: 1rem;
}

.about-section ol {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

footer {
    background-color: var(--dark-color);
    color: var(--light-color);
    padding: 2rem;
    text-align: center;
}

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

.footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin: 1rem 0;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--light-color);
    text-decoration: none;
    transition: var(--transition);
}

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

/* Loading spinner */
.spinner {
    display: none;
    width: 40px;
    height: 40px;
    margin: 0 auto;
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

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

/* Toast notification */
.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--dark-color);
    color: var(--light-color);
    padding: 1rem 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    transform: translateY(100px);
    opacity: 0;
    transition: var(--transition);
    z-index: 1000;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

/* Privacy modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 2000;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: var(--light-color);
    padding: 2rem;
    border-radius: var(--border-radius);
    max-width: 600px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    position: relative;
}

.modal-close {
    position: absolute;
    top: 1rem;
    right: 1rem;
    font-size: 1.5rem;
    cursor: pointer;
    background: none;
    border: none;
    color: var(--dark-color);
}

.modal h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.modal p {
    margin-bottom: 1rem;
}

@media (max-width: 768px) {
    .nav-links {
        gap: 0.5rem;
    }

    .preview-content {
        flex-direction: column;
    }

    .original-preview, .watermarked-preview {
        min-width: 100%;
    }
}

@media (max-width: 480px) {
    .nav-links {
        display: none;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .position-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}