:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --bg-light: #f8fafc;
    --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --card-hover-shadow: 0 10px 25px rgba(37, 99, 235, 0.15);
}

body {
    background-color: var(--bg-light);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1;
}

.navbar {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.navbar-brand {
    font-size: 1.3rem;
    letter-spacing: -0.5px;
}

.category-title {
    color: #334155;
    font-weight: 700;
    padding-bottom: 0.5rem;
    border-bottom: 3px solid var(--primary-color);
    display: inline-block;
}

.tool-card {
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    transition: all 0.3s ease;
    cursor: pointer;
    background: white;
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-hover-shadow);
    border-color: var(--primary-color);
}

.tool-card .card-title {
    color: #1e293b;
    font-weight: 600;
    font-size: 0.95rem;
}

.tool-card .card-text {
    font-size: 0.82rem;
    line-height: 1.4;
}

.tool-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
}

.tool-icon-large {
    width: 80px;
    height: 80px;
    margin: 0 auto;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.2rem;
}

.icon-word { background: linear-gradient(135deg, #e8f0fe, #c5d9f7); color: #2b579a; }
.icon-excel { background: linear-gradient(135deg, #e6f4ea, #b7e1cd); color: #217346; }
.icon-pptx { background: linear-gradient(135deg, #fce8e6, #f5c1bb); color: #d24726; }
.icon-txt { background: linear-gradient(135deg, #f3f0ff, #d9d2f0); color: #6c5ce7; }
.icon-rtf { background: linear-gradient(135deg, #e0f7fa, #b2ebf2); color: #00838f; }
.icon-html { background: linear-gradient(135deg, #fff3e0, #ffe0b2); color: #e65100; }
.icon-jpg { background: linear-gradient(135deg, #fce4ec, #f8bbd0); color: #c62828; }
.icon-png { background: linear-gradient(135deg, #e8f5e9, #c8e6c9); color: #2e7d32; }
.icon-tiff { background: linear-gradient(135deg, #efebe9, #d7ccc8); color: #4e342e; }
.icon-merge { background: linear-gradient(135deg, #e3f2fd, #bbdefb); color: #1565c0; }
.icon-split { background: linear-gradient(135deg, #fff8e1, #ffecb3); color: #f57f17; }
.icon-compress { background: linear-gradient(135deg, #f3e5f5, #e1bee7); color: #7b1fa2; }
.icon-rotate { background: linear-gradient(135deg, #e0f2f1, #b2dfdb); color: #00695c; }
.icon-protect { background: linear-gradient(135deg, #e8eaf6, #c5cae9); color: #283593; }
.icon-unlock { background: linear-gradient(135deg, #fff9c4, #fff176); color: #f9a825; }
.icon-watermark { background: linear-gradient(135deg, #e1f5fe, #b3e5fc); color: #0277bd; }

.upload-zone {
    border: 2px dashed #cbd5e1;
    border-radius: 16px;
    padding: 3rem 2rem;
    text-align: center;
    background: #f8fafc;
    transition: all 0.3s ease;
    cursor: pointer;
}

.upload-zone:hover,
.upload-zone.dragover {
    border-color: var(--primary-color);
    background: #eff6ff;
}

.upload-zone .upload-icon {
    font-size: 3rem;
    color: #94a3b8;
    display: block;
    margin-bottom: 1rem;
}

.upload-zone.dragover .upload-icon {
    color: var(--primary-color);
}

.category-filter .btn {
    border-radius: 20px;
    padding: 0.4rem 1.2rem;
    font-size: 0.9rem;
}

.category-section {
    scroll-margin-top: 80px;
}

.progress {
    height: 8px;
    border-radius: 4px;
}

.site-footer {
    background: #1e293b;
    color: #94a3b8;
    padding: 3rem 0 1.5rem;
    margin-top: auto;
}

.footer-heading {
    color: #f1f5f9;
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1.2rem;
}

.footer-text {
    font-size: 0.9rem;
    line-height: 1.7;
    color: #94a3b8;
}

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

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: #94a3b8;
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s ease;
}

.footer-links a:hover {
    color: #60a5fa;
}

.footer-divider {
    border-color: #334155;
    margin: 2rem 0 1rem;
}

.footer-copyright {
    font-size: 0.85rem;
    color: #64748b;
    margin-bottom: 0;
}

.developer-link {
    color: #60a5fa;
    text-decoration: none;
    font-weight: 500;
}

.developer-link:hover {
    color: #93c5fd;
    text-decoration: underline;
}

.page-content {
    background: white;
    border-radius: 12px;
    padding: 2.5rem;
    box-shadow: var(--card-shadow);
}

.page-title {
    color: #1e293b;
    font-weight: 700;
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 3px solid var(--primary-color);
    display: inline-block;
}

.page-content h2 {
    color: #334155;
    font-weight: 600;
    margin-top: 2rem;
    margin-bottom: 0.75rem;
    font-size: 1.4rem;
}

.page-content p, .page-content li {
    color: #475569;
    line-height: 1.8;
}

.page-content a {
    color: var(--primary-color);
}

.page-content a:hover {
    color: var(--primary-hover);
}

@media (max-width: 768px) {
    .display-5 {
        font-size: 1.8rem;
    }

    .upload-zone {
        padding: 2rem 1rem;
    }

    .tool-icon-large {
        width: 60px;
        height: 60px;
        font-size: 1.6rem;
    }

    .page-content {
        padding: 1.5rem;
    }

    .site-footer {
        padding: 2rem 0 1rem;
    }
}