* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Roboto, system-ui, sans-serif;
}

body {
    background: #f5f7fc;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
}

.card {
    max-width: 1100px;
    width: 100%;
    background: white;
    border-radius: 32px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.05), 0 6px 12px rgba(0, 0, 0, 0.1);
    padding: 32px;
    transition: all 0.2s;
}

h1 {
    font-weight: 600;
    font-size: 2rem;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
    color: #1e293b;
    display: flex;
    align-items: center;
    gap: 12px;
}

h1 i {
    color: #3b82f6;
    font-size: 2rem;
}

.subhead {
    color: #64748b;
    margin-bottom: 28px;
    border-left: 4px solid #3b82f6;
    padding-left: 18px;
    font-weight: 400;
}

.upload-area {
    border: 2px dashed #cbd5e1;
    border-radius: 24px;
    padding: 32px 24px;
    text-align: center;
    background: #fafbff;
    transition: border 0.2s, background 0.2s;
    cursor: pointer;
    margin-bottom: 30px;
}

.upload-area:hover, .drag-over {
    border-color: #3b82f6;
    background: #eef4ff;
}

.upload-area i {
    font-size: 48px;
    color: #64748b;
    margin-bottom: 12px;
}

.upload-area p {
    font-weight: 500;
    color: #1e293b;
}

.upload-area .hint {
    color: #94a3b8;
    font-size: 0.9rem;
    margin-top: 6px;
}

#file-input {
    display: none;
}

.btn {
    background: white;
    border: 1px solid #e2e8f0;
    padding: 10px 20px;
    border-radius: 60px;
    font-weight: 500;
    color: #1e293b;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 2px 6px rgba(0,0,0,0.02);
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: #3b82f6;
    border-color: #3b82f6;
    color: white;
    box-shadow: 0 6px 14px rgba(59,130,246,0.25);
}

.btn-primary:hover {
    background: #2563eb;
}

.btn-success {
    background: #10b981;
    border-color: #10b981;
    color: white;
}

.tree-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.tree-title {
    font-weight: 600;
    color: #0f172a;
}

.export-options {
    display: flex;
    align-items: center;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    color: #64748b;
    font-size: 0.9rem;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: #3b82f6;
    cursor: pointer;
}

.checkbox-label:hover {
    color: #1e293b;
}

.category-tree {
    margin-top: 10px;
    background: #f8fafc;
    border-radius: 20px;
    padding: 20px;
    max-height: 400px;
    overflow-y: auto;
}

.category-item {
    padding: 8px 12px;
    margin-bottom: 4px;
    border-radius: 12px;
    background: white;
    border: 1px solid #edf2f7;
    display: flex;
    align-items: center;
    transition: background 0.15s;
}

.category-item:hover {
    background: #f1f5f9;
}

.category-item label {
    flex: 1;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-weight: 500;
}

.category-item input[type="radio"] {
    accent-color: #3b82f6;
    width: 18px;
    height: 18px;
    margin-right: 4px;
}

.badge {
    background: #e2e8f0;
    color: #334155;
    border-radius: 40px;
    padding: 2px 12px;
    font-size: 0.8rem;
    font-weight: 500;
    margin-left: 8px;
}

.actions {
    display: flex;
    gap: 16px;
    margin-top: 24px;
    flex-wrap: wrap;
}

.msg {
    margin: 20px 0 0;
    padding: 14px 20px;
    border-radius: 18px;
    background: #f1f5f9;
    color: #0f172a;
}

.msg.error {
    background: #fee2e2;
    color: #b91c1c;
}

.fa-chevron-right {
    font-size: 12px;
    color: #94a3b8;
}