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

body {
    font-family: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: #f5f7fa;
    min-height: 100vh;
    padding: 20px 15px;
    color: #1a202c;
}

@media (min-width: 768px) {
    body {
        padding: 40px 20px;
    }
}

.app-header {
    text-align: center;
    margin-bottom: 24px;
}

.app-title {
    font-size: 20px;
    font-weight: 700;
    color: #2d3748;
    margin-bottom: 8px;
    letter-spacing: -0.5px;
    line-height: 1.3;
    padding: 0 10px;
}

.app-subtitle {
    font-size: 13px;
    color: #718096;
    font-weight: 500;
    padding: 0 10px;
    line-height: 1.5;
}

@media (min-width: 768px) {
    .app-header {
        margin-bottom: 40px;
    }

    .app-title {
        font-size: 28px;
        padding: 0;
    }

    .app-subtitle {
        font-size: 15px;
        padding: 0;
    }
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1), 0 10px 40px rgba(0,0,0,0.05);
    overflow: hidden;
}

.content {
    padding: 20px;
}

@media (min-width: 768px) {
    .content {
        padding: 40px;
    }
}

.info-banner {
    background: linear-gradient(135deg, #0ea5e9 0%, #0284c7 100%);
    padding: 16px 18px;
    margin-bottom: 24px;
    border-radius: 12px;
    color: white;
}

.info-banner h3 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.info-banner ul {
    list-style: none;
    font-size: 12px;
    line-height: 1.7;
    opacity: 0.95;
}

@media (min-width: 768px) {
    .info-banner {
        padding: 24px 28px;
        margin-bottom: 32px;
    }

    .info-banner h3 {
        font-size: 16px;
        margin-bottom: 12px;
        gap: 8px;
    }

    .info-banner ul {
        font-size: 14px;
        line-height: 1.8;
    }
}

.info-banner li:before {
    content: "✓";
    margin-right: 8px;
    font-weight: 700;
}

.upload-section {
    margin-bottom: 24px;
}

.section-header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
}

.section-number {
    width: 24px;
    height: 24px;
    background: #0ea5e9;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: 600;
    flex-shrink: 0;
}

.section-title {
    font-size: 15px;
    font-weight: 600;
    color: #2d3748;
    line-height: 1.4;
}

@media (min-width: 768px) {
    .upload-section {
        margin-bottom: 32px;
    }

    .section-header {
        gap: 10px;
        margin-bottom: 16px;
    }

    .section-number {
        width: 28px;
        height: 28px;
        font-size: 14px;
    }

    .section-title {
        font-size: 18px;
    }
}

.help-text {
    font-size: 12px;
    color: #718096;
    margin-bottom: 12px;
    padding: 0 4px;
    font-weight: 500;
}

@media (min-width: 768px) {
    .help-text {
        font-size: 13px;
        margin-bottom: 14px;
    }
}

.drop-zone {
    border: 2px dashed #cbd5e0;
    border-radius: 12px;
    padding: 24px 16px;
    text-align: center;
    background: #f7fafc;
    cursor: pointer;
    transition: all 0.2s ease;
    min-height: 120px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

@media (min-width: 768px) {
    .drop-zone {
        padding: 32px;
        min-height: auto;
    }
}

.drop-zone:hover {
    border-color: #0ea5e9;
    background: #e0f2fe;
}

.drop-zone.dragover {
    border-color: #0ea5e9;
    background: #bae6fd;
    border-style: solid;
    transform: scale(1.01);
}

.drop-zone-icon {
    font-size: 40px;
    margin-bottom: 12px;
    filter: grayscale(0.3);
}

.drop-zone-text {
    font-size: 16px;
    color: #2d3748;
    font-weight: 600;
    margin-bottom: 6px;
}

.drop-zone-hint {
    font-size: 14px;
    color: #718096;
}

.file-list {
    margin-top: 16px;
}

.file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px;
    background: #f7fafc;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    margin-bottom: 8px;
    gap: 8px;
    flex-wrap: wrap;
}

.file-item-info {
    display: flex;
    align-items: center;
    gap: 8px;
    flex: 1;
    min-width: 0;
}

.file-item-icon {
    font-size: 18px;
    flex-shrink: 0;
}

.file-item-name {
    font-size: 12px;
    font-weight: 500;
    color: #2d3748;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

@media (min-width: 768px) {
    .file-item {
        padding: 14px 16px;
        flex-wrap: nowrap;
    }

    .file-item-info {
        gap: 12px;
    }

    .file-item-icon {
        font-size: 20px;
    }

    .file-item-name {
        font-size: 14px;
        white-space: normal;
    }
}

.file-item-quarter {
    background: #0ea5e9;
    color: white;
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 12px;
    font-weight: 600;
}

.file-item-tag {
    background: #10b981;
    color: white;
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 11px;
    font-weight: 600;
}

.file-item-remove {
    background: transparent;
    color: #ef4444;
    border: 1px solid #ef4444;
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 11px;
    font-weight: 500;
    transition: all 0.2s;
    -webkit-tap-highlight-color: transparent;
    min-height: 36px;
    white-space: nowrap;
}

.file-item-remove:hover {
    background: #ef4444;
    color: white;
}

@media (min-width: 768px) {
    .file-item-remove {
        padding: 6px 14px;
        font-size: 13px;
    }
}

.button {
    background: linear-gradient(135deg, #0ea5e9 0%, #0284c7 100%);
    color: white;
    border: none;
    padding: 14px 24px;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    width: 100%;
    transition: all 0.2s;
    box-shadow: 0 4px 12px rgba(14, 165, 233, 0.3);
    -webkit-tap-highlight-color: transparent;
    min-height: 48px;
}

@media (min-width: 768px) {
    .button {
        padding: 16px 32px;
        font-size: 16px;
    }
}

.button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(14, 165, 233, 0.4);
}

.button:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.loading {
    display: none;
    text-align: center;
    padding: 24px;
}

.spinner {
    border: 3px solid #e2e8f0;
    border-top: 3px solid #0ea5e9;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 0.8s linear infinite;
    margin: 0 auto 16px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-text {
    color: #718096;
    font-size: 15px;
}

.success-message, .error-message {
    padding: 16px 18px;
    border-radius: 10px;
    margin-top: 20px;
    display: none;
    font-size: 13px;
    word-wrap: break-word;
}

@media (min-width: 768px) {
    .success-message, .error-message {
        padding: 20px 24px;
        margin-top: 24px;
        font-size: 15px;
    }
}

.success-message {
    background: #d1fae5;
    border: 1px solid #6ee7b7;
    color: #065f46;
}

.error-message {
    background: #fee2e2;
    border: 1px solid #fca5a5;
    color: #991b1b;
}

.download-link {
    display: inline-block;
    margin-top: 12px;
    background: #059669;
    color: white;
    padding: 10px 20px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 13px;
    transition: all 0.2s;
    -webkit-tap-highlight-color: transparent;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.download-link:hover {
    background: #047857;
    transform: translateY(-1px);
}

@media (min-width: 768px) {
    .download-link {
        margin-top: 16px;
        padding: 12px 24px;
        font-size: 14px;
    }
}

input[type="file"] {
    display: none;
}

.optional-badge {
    display: inline-block;
    background: #f59e0b;
    color: white;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 9px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.3px;
    margin-left: 6px;
}

@media (min-width: 768px) {
    .optional-badge {
        padding: 2px 8px;
        font-size: 11px;
        letter-spacing: 0.5px;
        margin-left: 8px;
    }
}

.footer {
    text-align: center;
    padding: 20px 15px;
    color: #94a3b8;
    font-size: 11px;
    border-top: 1px solid #e2e8f0;
    margin-top: 32px;
}

.footer-text {
    margin-bottom: 12px;
    line-height: 1.6;
}

@media (min-width: 768px) {
    .footer {
        padding: 24px;
        font-size: 13px;
        margin-top: 40px;
    }
}

.developer-name {
    color: #0ea5e9;
    font-weight: 600;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-top: 12px;
}

.social-link {
    color: #94a3b8;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.social-link:hover {
    color: #0ea5e9;
    transform: translateY(-2px);
}

.social-link svg {
    width: 24px;
    height: 24px;
}