.app-header { display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 22px 28px; background: var(--surface); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 10; }
.app-header h1 { margin: 0 0 6px; font-size: 24px; }
.app-header p { margin: 0; color: var(--muted); }
.header-actions, .action-row { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.app-shell { display: grid; grid-template-columns: 220px minmax(0, 1fr); min-height: calc(100vh - 86px); }
.side-nav { padding: 16px; border-left: 1px solid var(--border); background: #fbfcfc; }
.nav-item { display: block; width: 100%; border: 0; background: transparent; color: var(--muted); text-align: right; padding: 12px 14px; border-radius: var(--radius); margin-bottom: 4px; }
.nav-item.active, .nav-item:hover { background: var(--surface-alt); color: var(--primary-dark); }
.content { padding: 24px; min-width: 0; }
.page-section { display: none; }
.page-section.active { display: block; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 18px; }
.section-heading h2 { margin: 0; font-size: 22px; }
.section-heading p { margin: 0; color: var(--muted); }
.split-layout { display: grid; grid-template-columns: 1fr 1.2fr; gap: 22px; align-items: start; }
.upload-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.meta-form, .filters { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; margin: 16px 0; }
.chart-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; margin: 18px 0; }