body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: #f4f7f9;
    color: #333;
    margin: 0;
}

.container {
    width: 100%;
    max-width: 1600px;
    display: flex;
    flex-direction: column;
    height: 100vh;
    margin: 0 auto;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
    overflow: hidden;
}

body.report-view {
    padding: 0;
}

body.report-view header {
    display: none;
}

header {
    padding: 1em 2em;
    background-color: lightskyblue;
    width: 100%;
    box-sizing: border-box;
}

header h1 {
    margin: 0;
    font-size: 1.8em;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.header-description {
    margin: 0.25em 0 0 0;
    font-size: 0.9em;
    opacity: 0.9;
}

#main-content-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-height: 0;
}

.tab-navigation {
    display: flex;
    background-color: #ecf0f1;
    border-bottom: 1px solid #dcdcdc;
}

.tab-link {
    padding: 1em 1.5em;
    cursor: pointer;
    font-weight: 500;
    color: #555;
    border-bottom: 3px solid transparent;
    transition: all 0.3s ease;
    flex-grow: 1;
    text-align: center;
}

.tab-link:hover {
    background-color: #e0e6e8;
}

.tab-link.active {
    color: #2980b9;
    border-bottom-color: #2980b9;
    background-color: #fff;
}

#tab-content-wrapper {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
}

main {
    padding: 2.5em 2em;
}

.tab-content {
    display: none;
    padding-left: 1em;
}

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

.tab-content h2 {
    margin-top: 0; margin-block-end: 0.5em;
    color: #2980b9;
}

.tab-content p {
    line-height: 1.3;
    color: #555;
    margin-bottom: 0.5em; margin-block-start: 0.5em;
}

.form-container {
    padding-top: 1em;
    border-top: 1px solid #e0e0e0;
}

.form-group {
    margin-bottom: 1.0em;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5em;
}

input[type="file"], input[type="text"] {
    display: block;
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
    border: 1px solid #ccc;
    border-radius: 4px;
}

button, input[type="submit"] {
    display: inline-block;
    background-color: #28a745;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
    font-weight: 600;
}

button:hover, input[type="submit"]:hover {
    background-color: #218838;
}

.spinner {
    display: none;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #3498db;
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
    margin-top: 1em;
}

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

@media (max-width: 768px) {
    header {
        padding: 0.25em 1em;
    }
    .header-description {
        font-size: 1em;
    }
    .tab-link { padding: 0em 0.5em; }
    .tab-content h2 { margin-block-end: 0; }
    .tab-content p { margin-block-start: 0.1em; }
}