* { box-sizing: border-box; }
body { margin: 0; font-family: system-ui, sans-serif; background: #2c3e50; color: #ecf0f1; padding: 1rem; }
.viewer-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 1rem; flex-wrap: wrap; gap: 0.5rem; }
.viewer-header h1 { margin: 0; font-size: 1.1rem; font-weight: 600; }
.viewer-nav { display: flex; align-items: center; gap: 1rem; }
.viewer-hint { font-size: 0.9rem; color: #bdc3c7; }
.viewer-area {
    width: 100%;
    height: calc(100vh - 96px);
    min-height: 560px;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    background: #1f2d3a;
}
.viewer-iframe {
    width: 100%;
    height: 100%;
    border: 0;
    background: #1f2d3a;
}
.btn-dl { padding: 6px 12px; background: #27ae60; color: white; text-decoration: none; border-radius: 6px; font-size: 0.85rem; }
.btn-dl:hover { background: #229954; color: white; }
.btn-submit { background: #1f78d1; }
.btn-submit:hover { background: #1664ad; }
.viewer-hidden-input { display: none; }

.pdf-submit-overlay {
    position: fixed;
    inset: 0;
    z-index: 20000;
    background: rgba(15, 23, 42, 0.72);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
}
.pdf-submit-overlay[hidden] { display: none !important; }
.pdf-submit-overlay-box {
    max-width: 420px;
    background: #1f2d3a;
    color: #ecf0f1;
    border-radius: 10px;
    padding: 1.25rem 1.5rem;
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.45);
    text-align: center;
}
.pdf-submit-overlay-title {
    margin: 0.75rem 0 0.35rem;
    font-weight: 600;
    font-size: 1rem;
}
.pdf-submit-overlay-text {
    margin: 0;
    font-size: 0.88rem;
    color: #bdc3c7;
    line-height: 1.45;
}
.pdf-submit-spinner {
    width: 36px;
    height: 36px;
    margin: 0 auto;
    border-radius: 50%;
    border: 3px solid rgba(236, 240, 241, 0.25);
    border-top-color: #1f78d1;
    animation: pdf-submit-spin 0.85s linear infinite;
}
@keyframes pdf-submit-spin {
    to { transform: rotate(360deg); }
}