:root { color-scheme: light; font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; background: #f5f6fa; color: #182333; }
* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; }
.shell { width: min(100% - 2rem, 820px); margin: 0 auto; padding: 2.5rem 0 3.5rem; }
.masthead { border-bottom: 4px solid #295b97; padding-bottom: 1.35rem; }
.eyebrow, .step-kicker { color: #295b97; font-size: .81rem; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
h1 { font-size: clamp(2rem, 7vw, 3.65rem); line-height: 1; letter-spacing: -.045em; margin: .25rem 0 .8rem; }
h2 { font-size: clamp(1.35rem, 4vw, 2rem); line-height: 1.1; margin: .2rem 0 .75rem; }
p, li { font-size: 1.03rem; line-height: 1.65; }
.boundary { background: #fff4d7; border-left: 5px solid #b06f00; margin: 1.5rem 0; padding: .9rem 1rem; }
.activity-source { border-left: 5px solid #295b97; }
.activity-source p:last-child { margin-bottom: 0; }
.activity-checks { border-left: 5px solid #295b97; }
.activity-derived-note { color: #536273; }
.notebook-checklist { display: grid; gap: .7rem; margin: 1rem 0; padding: 0; list-style: none; }
.notebook-checklist li { border-bottom: 1px solid #dbe3ec; padding-bottom: .7rem; }
.notebook-checklist li:last-child { border-bottom: 0; }
.notebook-checklist .checkbox-label { font-weight: 600; }
.completion-boundary { border-top: 1px solid #dbe3ec; margin-top: 1rem; padding-top: 1rem; }
.panel { background: #fff; border: 1px solid #cad4e2; border-radius: 14px; margin-top: 1.25rem; padding: 1.3rem; }
.field-grid, .checklist-grid { display: grid; gap: 1rem; grid-template-columns: repeat(2, minmax(0, 1fr)); }
.progress-label { color: #536273; font-size: .93rem; font-weight: 700; margin: 0 0 .65rem; }
.progress-track { background: #dde6f0; border-radius: 999px; height: .65rem; overflow: hidden; }
#progress-bar { background: #295b97; border-radius: inherit; display: block; height: 100%; transition: width .2s ease; }
.summary { color: #47576a; font-size: 1.14rem; }
.step-content { border-top: 1px solid #dbe3ec; margin-top: 1.1rem; padding-top: .9rem; }
.step-content ul { padding-left: 1.25rem; }
.step-content code { background: #edf2f9; border-radius: 4px; padding: .1rem .28rem; }
.activity-step-instructions { background: #edf4fc; border: 1px solid #a8bed9; border-left: 5px solid #295b97; border-radius: 10px; padding: 1rem 1.05rem; }
.activity-step-instructions h3 { margin: 0 0 .5rem; }
.activity-step-instructions h4 { border-top: 1px solid #c5d5e7; margin: 1rem 0 .35rem; padding-top: .85rem; }
.activity-step-instructions p { margin: 0; }
.step-resources { display: grid; gap: .35rem; margin: .35rem 0 0; overflow-wrap: anywhere; }
.notebook-role p { margin-bottom: 0; }
label { display: grid; gap: .35rem; font-weight: 750; margin: 1rem 0 .35rem; }
label span, .hint { color: #536273; font-size: .9rem; font-weight: 500; }
input, textarea, button { font: inherit; }
input, textarea { width: 100%; border: 1px solid #8b9bb0; border-radius: 8px; padding: .65rem .75rem; color: #182333; background: #fff; }
textarea { min-height: 7rem; resize: vertical; }
.structured-field, .step-note { border-top: 1px solid #dbe3ec; margin-top: 1rem; padding-top: 1rem; }
.controls { display: flex; gap: .75rem; justify-content: space-between; margin-top: 1.25rem; }
button { background: #295b97; border: 2px solid #295b97; border-radius: 8px; color: #fff; cursor: pointer; font-weight: 750; padding: .72rem 1.15rem; }
button.secondary { background: #fff; color: #295b97; }
button:disabled { cursor: not-allowed; opacity: .45; }
button:focus-visible, input:focus-visible, textarea:focus-visible, a:focus-visible { outline: 3px solid #d48a00; outline-offset: 3px; }
.stacked-fields { display: grid; gap: .75rem; }
fieldset { border: 1px solid #cad4e2; border-radius: 10px; margin: 1.5rem 0 0; padding: .8rem 1rem 1rem; }
legend { font-weight: 800; padding: 0 .3rem; }
.extension-item { border-top: 1px solid #dbe3ec; padding: .85rem 0; }
.extension-item:first-child { border-top: 0; }
.checkbox-label { display: flex; align-items: flex-start; gap: .65rem; margin-top: 0; }
.checkbox-label input { width: auto; margin-top: .3rem; }
.extension-item textarea { min-height: 4.5rem; margin-top: .55rem; }
.feedback textarea { min-height: 6rem; }
.action-buttons { display: flex; flex-wrap: wrap; gap: .7rem; }
.status { min-height: 1.5rem; color: #8d4f00; font-weight: 700; }
footer { color: #526171; font-size: .92rem; margin-top: 1.5rem; }
a { color: #18528f; font-weight: 700; }
.footer-actions { display: flex; flex-wrap: wrap; gap: .7rem; }
.footer-button { display: inline-block; border: 1px solid #295b97; border-radius: 8px; padding: .5rem .8rem; background: #295b97; color: #fff; font-weight: 800; text-decoration: none; }
.footer-button:hover { background: #214b7e; color: #fff; }
.footer-button-secondary { background: #fff; color: #295b97; }
.footer-button-secondary:hover { background: #edf2f9; color: #295b97; }
@media (max-width: 540px) { .shell { width: min(100% - 1.25rem, 820px); padding-top: 1.25rem; } .panel { padding: 1rem; } .field-grid { grid-template-columns: 1fr; } .controls button { flex: 1; } }