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

body {
    font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, Roboto, Oxygen, Ubuntu, sans-serif;
    background: linear-gradient(145deg, #fbe9e7 0%, #ffccbc 100%);
    min-height: 100vh;
    padding: 20px;
}

.app-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    min-height: calc(100vh - 40px);
}

header {
    text-align: center;
    margin-bottom: 30px;
}

h1 {
    color: #bf360c;
    font-size: 2.5rem;
    margin-bottom: 5px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.05);
    font-weight: 600;
    letter-spacing: -0.5px;
}

.subtitle {
    color: #d84315;
    font-size: 1.1rem;
    font-weight: 400;
}

.converter-box {
    background: #fffaf0;
    border-radius: 32px;
    box-shadow: 0 20px 35px -8px rgba(191, 54, 12, 0.2), 0 5px 10px -4px rgba(0,0,0,0.05);
    padding: 30px;
    border: 1px solid #ffe0b2;
    flex: 1;
}

.upload-area {
    border: 3px dashed #ffb74d;
    border-radius: 24px;
    padding: 40px 20px;
    text-align: center;
    background: #fff5e6;
    transition: all 0.2s ease;
    cursor: pointer;
}

.upload-area:hover {
    border-color: #e65100;
    background: #fff3e0;
}

.upload-area.dragover {
    border-color: #e65100;
    background: #ffe0b2;
    transform: scale(1.01);
}

.upload-area.has-file {
    border-style: solid;
    background: #fff8e1;
}

.upload-icon {
    font-size: 4rem;
    margin-bottom: 15px;
}

.upload-text {
    font-size: 1.3rem;
    color: #bf360c;
    margin-bottom: 8px;
    font-weight: 500;
}

.upload-hint {
    color: #a1887f;
    margin-bottom: 20px;
}

.primary-btn {
    background: #e65100;
    color: white;
    border: none;
    padding: 14px 30px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 60px;
    cursor: pointer;
    box-shadow: 0 8px 16px rgba(230, 81, 0, 0.3);
    transition: all 0.2s;
    border: 1px solid #ffb74d;
}

.primary-btn:hover {
    background: #bf360c;
    transform: translateY(-3px);
    box-shadow: 0 12px 20px rgba(230, 81, 0, 0.4);
}

.secondary-btn {
    background: #ffecb3;
    color: #bf360c;
    border: 1px solid #ffb74d;
    padding: 14px 30px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 60px;
    cursor: pointer;
    transition: all 0.2s;
}

.secondary-btn:hover {
    background: #ffe0b2;
    transform: translateY(-2px);
}

.file-name {
    margin-top: 15px;
    color: #d84315;
    font-weight: 500;
}

.preview-section {
    margin-top: 30px;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 15px;
}

.section-header h2 {
    color: #bf360c;
    font-size: 1.6rem;
}

.row-count {
    background: #ffcc80;
    padding: 6px 16px;
    border-radius: 30px;
    color: #3e2723;
    font-weight: 500;
    font-size: 0.9rem;
}

.table-wrapper {
    max-height: 400px;
    overflow: auto;
    border-radius: 18px;
    border: 1px solid #ffe0b2;
    background: white;
    margin-bottom: 25px;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.95rem;
}

th {
    background: #ffb74d;
    color: #3e2723;
    padding: 14px 12px;
    text-align: left;
    font-weight: 600;
    position: sticky;
    top: 0;
    white-space: nowrap;
}

td {
    padding: 10px 12px;
    border-bottom: 1px solid #ffe0b2;
}

tr:nth-child(even) {
    background: #fff8e1;
}

tr:hover {
    background: #ffecb3;
}

.action-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
}

.error-message {
    background: #ffebee;
    color: #c62828;
    padding: 15px 20px;
    border-radius: 40px;
    margin-top: 20px;
    border-left: 6px solid #b71c1c;
    font-weight: 500;
}

.loading {
    text-align: center;
    padding: 20px;
    font-size: 1.3rem;
    color: #e65100;
}

.hidden {
    display: none;
}

footer.info {
    text-align: center;
    margin-top: 25px;
    color: #bf360c;
    font-size: 0.9rem;
    font-weight: 500;
    opacity: 0.8;
}

@media (max-width: 600px) {
    .converter-box {
        padding: 20px;
    }
    h1 {
        font-size: 2rem;
    }
    .action-buttons {
        flex-direction: column;
    }
    .primary-btn, .secondary-btn {
        width: 100%;
    }
}