/* First Comet course: reuse the workspace palette, type, outlines, and shadows. */
.project-path-intro { display: grid; grid-template-columns: minmax(0, 1fr) 210px; gap: 28px; padding: 26px; border: 2px solid var(--line); border-radius: 14px; background: var(--panel); }
.project-path-intro h2 { font-size: clamp(1.5rem, 2.5vw, 2rem); line-height: 1.2; margin: 10px 0 16px; }
.project-path-intro p, .project-connections > p { color: var(--muted); line-height: 1.65; }
.project-path-intro .primary { margin-top: 12px; }
.project-path-total { display: flex; flex-direction: column; justify-content: center; gap: 10px; }
.project-path-total > span { display: grid; place-items: center; width: 48px; height: 48px; border: 2px solid var(--line); border-radius: 50%; background: var(--yellow); color: #171319; font-size: 1.8rem; }
.project-path-total b { font-size: 1.65rem; }
.project-path-total small { color: var(--muted); line-height: 1.5; font-size: .76rem; }
.project-path-total progress { width: 100%; accent-color: var(--coral); }
.project-subject-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); list-style: none; gap: 16px; padding: 0; margin: 24px 0 40px; }
.project-subject-card { display: grid; grid-template-columns: 42px minmax(0, 1fr); align-content: start; gap: 16px; padding: 22px; border: 2px solid var(--line); border-radius: 14px; background: var(--panel); min-width: 0; }
.project-step { display: grid; place-items: center; width: 42px; height: 42px; font: 700 .95rem 'DM Mono', monospace; color: #171319; border: 2px solid var(--line); border-radius: 9px; }
.project-step.coral { background: var(--coral); }
.project-step.blue { background: #a7d0ff; }
.project-step.yellow { background: var(--yellow); }
.project-subject-card h3 { margin: 7px 0 8px; font-size: 1.15rem; line-height: 1.3; }
.project-subject-card p { margin: 0 0 9px; line-height: 1.5; font-size: .86rem; }
.project-subject-card small { color: var(--muted); line-height: 1.6; font-size: .76rem; display: block; }
.project-subject-footer { grid-column: 1 / -1; display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; border-top: 1px solid var(--muted); padding-top: 12px; }
.project-subject-footer button { font-size: .83rem; }
.project-code-links { grid-column: 1 / -1; display: flex; flex-wrap: wrap; gap: 8px; }
.project-code-links a { color: var(--ink); border: 1px solid var(--line); background: var(--cream); border-radius: 6px; padding: 6px 9px; font-size: .78rem; font-weight: 700; }
.project-code-links p { flex-basis: 100%; margin: 3px 0 0; color: var(--muted); font-size: .75rem; }
.project-connections h2 { margin: 10px 0; font-size: 1.5rem; }
.project-table { margin-top: 20px; }
.project-table table { min-width: 650px; }
.project-course-toolbar { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; }
.project-course-toolbar label { display: block; margin-bottom: 6px; font-size: .75rem; font-weight: 700; }
.project-course-toolbar select { color: var(--ink); background: var(--panel); border: 2px solid var(--line); border-radius: 8px; padding: 10px 12px; font: inherit; font-size: .82rem; max-width: 100%; }
.project-next-link { display: block; text-align: center; text-decoration: none; box-sizing: border-box; }
@media (max-width: 760px) {
  .project-path-intro { grid-template-columns: 1fr; padding: 20px; }
  .project-path-total { max-width: 320px; }
  .project-subject-grid { grid-template-columns: 1fr; }
}
@media (max-width: 520px) {
  .project-path-intro { padding: 16px; }
  .project-subject-card { padding: 16px; gap: 12px; grid-template-columns: 34px minmax(0, 1fr); }
  .project-step { width: 34px; height: 34px; font-size: .8rem; }
  .project-subject-card .eyebrow { font-size: .55rem; }
  .project-course-toolbar > div { width: 100%; }
  .project-course-toolbar select { width: 100%; }
}
.learn-section[hidden] { display: none !important; }
.app:has(#view-learn.active) > .command-bar { display: none; }
.course-page-heading h1 { font-size: clamp(1.9rem, 3.4vw, 3rem); line-height: 1.08; letter-spacing: -.04em; }
.course-page-heading p { max-width: 760px; line-height: 1.65; }
.learn-sections, .course-tabs, .course-algorithm-code nav { display: flex; flex-wrap: wrap; gap: 8px; }
.learn-sections { margin: 24px 0; }
.learn-sections button, .course-tabs button, .course-algorithm-code nav button { border: 2px solid var(--line); border-radius: 9px; background: var(--panel); color: var(--ink); padding: 11px 16px; cursor: pointer; font-weight: 700; }
.learn-sections button.active, .course-tabs button.active, .course-algorithm-code nav button.active { background: var(--yellow); color: #171319; box-shadow: 3px 3px 0 var(--line); }
.course-start-note { display: flex; gap: 16px; align-items: flex-start; border: 2px solid var(--line); border-radius: 14px; padding: 20px 22px; background: var(--panel); }
.course-start-note > span { flex: 0 0 40px; display: grid; place-items: center; border: 2px solid var(--line); border-radius: 50%; background: var(--yellow); color: #171319; width: 40px; height: 40px; font-size: 1.4rem; }
.course-start-note b { font-size: 1rem; }
.course-start-note p { margin: 7px 0 10px; line-height: 1.6; color: var(--muted); max-width: 960px; }
.course-text-link { border: 0; padding: 3px 0; background: transparent; color: var(--ink); text-align: left; font-weight: 700; text-decoration: underline; text-underline-offset: 3px; cursor: pointer; line-height: 1.5; }
.course-languages { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; margin: 22px 0; }
.course-language { display: flex; align-items: center; gap: 12px; min-width: 0; border: 2px solid var(--line); border-radius: 12px; background: var(--panel); color: var(--ink); padding: 14px; cursor: pointer; text-align: left; transition: transform .15s; }
.course-language:hover { transform: translateY(-2px); }
.course-language.active { background: var(--cream); box-shadow: 4px 4px 0 var(--line); }
.course-language b, .course-language small { display: block; }
.course-language b { font-size: 1rem; }
.course-language small { margin-top: 4px; line-height: 1.35; font-size: .73rem; color: var(--muted); }
.language-badge { display: grid; place-items: center; flex: 0 0 40px; height: 40px; border: 2px solid var(--line); border-radius: 8px; font: 700 .85rem 'DM Mono', monospace; color: #171319; }
.language-badge.coral { background: var(--coral); }
.language-badge.blue { background: #a7d0ff; }
.language-badge.yellow { background: var(--yellow); }
.course-track-brief { display: grid; grid-template-columns: 1fr 250px; gap: 28px; align-items: center; padding: 26px; margin: 26px 0; border: 2px solid var(--line); border-radius: 14px; background: var(--panel); }
.course-track-brief h2 { font-size: 1.8rem; margin: 8px 0 10px; line-height: 1.2; }
.course-track-brief p { color: var(--muted); line-height: 1.6; margin: 0; max-width: 660px; }
.course-track-progress { display: grid; gap: 9px; }
.course-track-progress b { font-size: .83rem; }
.course-track-progress label { font-size: .75rem; color: var(--muted); }
.course-track-progress progress { display: block; width: 100%; height: 11px; accent-color: var(--coral); border: 0; }
.course-track-progress progress::-webkit-progress-bar { background: var(--cream); border-radius: 20px; }
.course-track-progress progress::-webkit-progress-value { background: var(--coral); border-radius: 20px; }
.course-track-progress progress::-moz-progress-bar { background: var(--coral); border-radius: 20px; }
.course-tabs { border-bottom: 2px solid var(--line); padding-bottom: 16px; }
.course-tabs button { font-size: .85rem; }
.course-panel-head { display: flex; align-items: flex-end; justify-content: space-between; margin: 30px 0 20px; }
.course-panel-head h2 { font-size: 1.5rem; margin: 9px 0; line-height: 1.25; }
.course-panel-head p { color: var(--muted); line-height: 1.65; max-width: 800px; margin: 0; }
.course-dictionary-tools { display: grid; grid-template-columns: 1fr 210px; gap: 14px; align-items: end; }
.course-dictionary-tools label, .course-compare-filter label, .course-trace-heading label { display: block; font-weight: 700; font-size: .8rem; margin-bottom: 8px; }
.course-dictionary-tools input, .course-dictionary-tools select, .course-compare-filter select, .course-trace-heading select { color: var(--ink); background: var(--panel); border: 2px solid var(--line); border-radius: 9px; padding: 12px 14px; width: 100%; min-width: 0; font: inherit; font-size: .86rem; }
.course-dictionary-tools input::placeholder { color: var(--muted); opacity: 1; }
.course-result-count { color: var(--muted); font-size: .75rem; margin: 15px 0; }
.course-word-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); align-items: start; gap: 12px; }
.course-word { min-width: 0; border: 2px solid var(--line); border-radius: 12px; background: var(--panel); overflow: hidden; }
.course-word summary { display: flex; align-items: flex-start; justify-content: space-between; gap: 12px; padding: 18px; list-style: none; cursor: pointer; }
.course-word summary::-webkit-details-marker { display: none; }
.course-word summary h3 { font-size: 1.03rem; margin: 6px 0; line-height: 1.3; }
.course-word summary p { color: var(--muted); font-size: .84rem; line-height: 1.55; margin: 0; }
.word-track { font: 500 .6rem 'DM Mono', monospace; letter-spacing: .08em; color: var(--muted); text-transform: uppercase; }
.word-expand { flex: 0 0 25px; text-align: center; font-size: 1.2rem; }
.course-word[open] { box-shadow: 3px 3px 0 var(--line); }
.course-word[open] .word-expand { transform: rotate(45deg); }
.word-body { padding: 0 18px 18px; }
.word-body p { font-size: .85rem; line-height: 1.65; }
.word-note { border-left: 3px solid var(--coral); padding-left: 12px; color: var(--muted); }
.course-code { border: 2px solid var(--line); border-radius: 10px; overflow: hidden; margin: 18px 0; min-width: 0; }
.course-code > div { display: flex; justify-content: space-between; align-items: center; gap: 8px; background: var(--cream); padding: 9px 12px; border-bottom: 2px solid var(--line); }
.course-code > div > span { font: 500 .64rem 'DM Mono', monospace; text-transform: uppercase; letter-spacing: .05em; }
.course-code button { border: 1px solid var(--line); border-radius: 5px; background: var(--panel); color: var(--ink); padding: 5px 8px; font-size: .68rem; cursor: pointer; flex-shrink: 0; }
.course-code pre, .course-compare-table pre { white-space: pre; overflow-x: auto; margin: 0; padding: 18px; background: #1d1a20; color: #fff5dc; font: .79rem/1.75 'DM Mono', monospace; tab-size: 4; }
.course-code pre code, .course-compare-table pre code { background: transparent; border: 0; border-radius: 0; padding: 0; color: inherit; font: inherit; }
.course-sources { display: flex; flex-wrap: wrap; gap: 8px 14px; margin-top: 24px; padding-top: 18px; border-top: 1px solid var(--muted); font-size: .76rem; line-height: 1.6; }
.course-sources span { color: var(--muted); }
.course-sources a { color: var(--ink); text-underline-offset: 3px; }
.course-save-note { font-size: .74rem; line-height: 1.6; color: var(--muted); margin: 24px 0 0; }
.course-download { display: inline-block; color: var(--ink); font-weight: 700; font-size: .8rem; margin-top: 12px; text-underline-offset: 3px; }
.course-empty { grid-column: 1 / -1; border: 2px dashed var(--line); padding: 20px; border-radius: 10px; }
.course-empty h3 { margin: 0 0 8px; }
.course-empty p { margin: 0; line-height: 1.6; }
.course-run-guide { background: var(--cream); border: 2px solid var(--line); border-radius: 10px; padding: 14px 18px; margin: 16px 0 20px; }
.course-run-guide summary { font-size: .85rem; font-weight: 700; cursor: pointer; }
.course-run-guide p { line-height: 1.7; font-size: .87rem; }
.course-milestone-layout { display: grid; grid-template-columns: 265px minmax(0, 1fr); gap: 20px; align-items: start; }
.course-milestone-nav { display: grid; gap: 8px; }
.course-milestone-nav button { display: flex; gap: 12px; align-items: flex-start; text-align: left; border: 2px solid var(--line); border-radius: 10px; padding: 13px 12px; background: var(--panel); color: var(--ink); cursor: pointer; }
.course-milestone-nav button.active { background: var(--cream); box-shadow: 3px 3px 0 var(--line); }
.course-milestone-nav button > span { flex: 0 0 27px; font: 700 .8rem 'DM Mono', monospace; padding-top: 2px; }
.course-milestone-nav b { display: block; font-size: .83rem; line-height: 1.4; }
.course-milestone-nav small { display: block; margin-top: 6px; font-size: .67rem; color: var(--muted); line-height: 1.4; }
.course-milestone-nav button:disabled, .course-algorithm-milestones nav button:disabled { cursor: default; opacity: .6; }
.course-milestone-body, .course-algorithm-milestones article { min-width: 0; background: var(--panel); border: 2px solid var(--line); border-radius: 14px; padding: 26px; }
.course-milestone-body h3, .course-algorithm-milestones article h3 { font-size: 1.45rem; line-height: 1.3; margin: 10px 0; }
.course-milestone-body > p, .course-algorithm-milestones article > p { line-height: 1.7; }
.course-goal { border-left: 4px solid var(--coral); padding-left: 12px; }
.course-word-chips { display: flex; flex-wrap: wrap; gap: 7px; align-items: center; margin: 20px 0; }
.course-word-chips > span { font-size: .72rem; color: var(--muted); }
.course-word-chips button { border: 1px solid var(--line); border-radius: 6px; padding: 5px 8px; background: var(--cream); color: var(--ink); font-size: .7rem; cursor: pointer; }
.course-lines h4, .course-output h4, .course-practice h4 { margin: 0 0 12px; font-size: .91rem; }
.course-lines ol { margin: 0; padding-left: 24px; }
.course-lines li { padding: 4px 0; font-size: .86rem; line-height: 1.65; }
.course-output { border: 1px dashed var(--muted); border-radius: 9px; padding: 16px; margin: 20px 0; }
.course-output pre { white-space: pre-wrap; overflow-wrap: anywhere; margin: 0; font: .82rem/1.65 'DM Mono', monospace; }
.course-practice { background: var(--cream); border: 2px solid var(--line); border-radius: 10px; padding: 18px; margin: 22px 0; }
.course-practice p { line-height: 1.65; margin: 0; font-size: .86rem; }
.course-check { border-top: 2px solid var(--line); padding-top: 20px; margin-top: 22px; }
.course-check fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
.course-check legend { font-weight: 700; line-height: 1.5; font-size: .95rem; margin-bottom: 14px; }
.course-check fieldset label, .course-practice-confirm { display: flex; align-items: flex-start; gap: 10px; border: 1px solid var(--muted); border-radius: 8px; padding: 12px; margin-bottom: 8px; cursor: pointer; font-size: .85rem; line-height: 1.5; }
.course-check input { flex: 0 0 16px; width: 16px; height: 16px; margin: 2px 0 0; accent-color: var(--coral); }
.course-practice-confirm { border: 0; padding: 12px 0; margin-top: 10px; }
.course-check-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 12px; }
.course-check-feedback { line-height: 1.65; font-size: .86rem; margin: 15px 0 0; }
.course-check-feedback:empty { margin: 0; }
.course-check-feedback[data-result="retry"] { border-left: 3px solid var(--coral); padding: 6px 12px; }
.course-check-feedback[data-result="correct"], .course-done-tag { border-left: 3px solid #59a857; padding: 8px 12px; }
.course-done-tag { font-size: .8rem; }
.course-next { width: 100%; background: var(--yellow); color: #171319; border: 2px solid var(--line); border-radius: 9px; padding: 14px; margin-top: 18px; font-weight: 700; cursor: pointer; }
.course-table-scroll { width: 100%; min-width: 0; overflow-x: auto; border: 2px solid var(--line); border-radius: 10px; background: var(--panel); }
.course-table-scroll table { width: 100%; border-collapse: collapse; font-size: .82rem; }
.course-table-scroll caption { text-align: left; padding: 16px; font-weight: 700; border-bottom: 2px solid var(--line); }
.course-table-scroll th, .course-table-scroll td { text-align: left; vertical-align: top; padding: 14px; border: 1px solid var(--muted); line-height: 1.6; }
.course-table-scroll thead { background: var(--cream); }
.course-role-table { margin-bottom: 24px; }
.course-role-table h3 { font-size: 1.03rem; }
.course-role-table table { min-width: 620px; }
.course-role-table code { white-space: normal; overflow-wrap: anywhere; font-size: .75rem; }
.course-role-table > p { color: var(--muted); line-height: 1.65; font-size: .83rem; }
.course-compare-filter { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 16px; margin: 24px 0 12px; }
.course-compare-filter label { margin: 0; }
.course-compare-filter select { width: 180px; padding: 8px 12px; }
.course-compare-filter span { color: var(--muted); font-size: .73rem; }
.course-compare-table { min-width: 1200px; }
.course-compare-table th { min-width: 190px; }
.course-compare-table th small { display: block; margin-top: 10px; color: var(--muted); font-weight: 400; font-size: .76rem; }
.course-compare-table td { min-width: 245px; }
.course-compare-table pre { padding: 12px; border-radius: 6px; font-size: .73rem; }
.course-compare-table .course-compare-note td { background: var(--cream); font-size: .78rem; padding: 10px 16px; }
.course-compare-reminder { padding: 20px; margin: 24px 0; border: 2px solid var(--line); border-radius: 10px; background: var(--panel); }
.course-compare-reminder p { font-size: .86rem; line-height: 1.7; }
.course-algorithm-definition { border: 2px solid var(--line); border-radius: 12px; background: var(--panel); padding: 24px; }
.course-algorithm-definition h3 { margin-top: 0; font-size: 1.1rem; }
.course-algorithm-definition p { font-size: .9rem; line-height: 1.75; }
.course-algorithm-words { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; margin: 20px 0; }
.course-algorithm-words > div { border: 2px solid var(--line); border-radius: 10px; padding: 15px; background: var(--panel); }
.course-algorithm-words dt { font-weight: 700; font-size: .85rem; }
.course-algorithm-words dd { margin: 7px 0 0; color: var(--muted); font-size: .78rem; line-height: 1.55; }
.course-trace { border: 2px solid var(--line); border-radius: 12px; padding: 24px; background: var(--panel); }
.course-trace-heading { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.course-trace-heading h3 { font-size: 1.2rem; margin: 8px 0 0; }
.course-trace-numbers { display: grid; grid-template-columns: repeat(7, minmax(0, 1fr)); gap: 8px; margin-top: 24px; }
.course-trace-numbers > div { position: relative; border: 2px solid var(--line); border-radius: 8px; padding: 14px 4px 12px; text-align: center; background: var(--paper); }
.course-trace-numbers span { display: block; font: 700 1.25rem 'DM Mono', monospace; }
.course-trace-numbers small { display: block; font-size: .64rem; color: var(--muted); margin-top: 8px; }
.course-trace-numbers .discarded { opacity: .35; }
.course-trace-numbers .middle { background: var(--yellow); color: #171319; box-shadow: 3px 3px 0 var(--line); }
.course-trace-numbers .middle small { color: #574647; }
.course-trace-numbers .found { background: #c4e6bc; }
.course-trace-numbers b { display: block; font-size: .6rem; margin-top: 7px; }
.course-trace-legend { color: var(--muted); font-size: .72rem; line-height: 1.6; }
.course-trace-values { display: flex; gap: 20px; margin: 20px 0; }
.course-trace-values div { display: flex; gap: 7px; align-items: center; }
.course-trace-values dt { font-size: .8rem; color: var(--muted); }
.course-trace-values dd { margin: 0; font: 700 .9rem 'DM Mono', monospace; }
.course-trace-description { line-height: 1.7; font-size: .88rem; }
.course-trace-controls { display: flex; flex-wrap: wrap; gap: 10px; }
.course-trace-controls button:disabled { opacity: .6; cursor: default; box-shadow: none; }
.course-algorithm-milestones { display: grid; grid-template-columns: 260px minmax(0, 1fr); gap: 20px; margin-top: 28px; align-items: start; }
.course-algorithm-milestones nav { display: grid; gap: 10px; }
.course-algorithm-milestones nav button { display: flex; gap: 12px; text-align: left; padding: 16px; background: var(--panel); border: 2px solid var(--line); border-radius: 10px; cursor: pointer; color: var(--ink); font-size: .84rem; font-weight: 700; line-height: 1.5; }
.course-algorithm-milestones nav button.active { background: var(--cream); box-shadow: 3px 3px 0 var(--line); }
.course-algorithm-code { margin-top: 32px; }
.course-algorithm-code h3 { font-size: 1.2rem; }
.course-algorithm-code > p { line-height: 1.65; color: var(--muted); font-size: .87rem; }
.course-section-intro { margin: 24px 0; }
.course-section-intro h2 { font-size: 1.7rem; }
.course-section-intro p { color: var(--muted); line-height: 1.6; }
#courseApp button:focus-visible, #courseApp summary:focus-visible, .learn-sections button:focus-visible, #courseApp input:focus-visible, #courseApp select:focus-visible, #courseApp .course-table-scroll:focus-visible { outline: 3px solid var(--blue); outline-offset: 4px; }
#courseApp .primary { color: #171319; }
@media (max-width: 1050px) {
  .course-milestone-layout, .course-algorithm-milestones { grid-template-columns: 1fr; }
  .course-milestone-nav { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .course-algorithm-milestones nav { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}
@media (max-width: 800px) {
  .rail nav { grid-template-columns: repeat(5, minmax(0, 1fr)); }
}
@media (max-width: 760px) {
  .course-track-brief { grid-template-columns: 1fr; padding: 20px; gap: 20px; }
  .course-track-progress { max-width: 340px; }
  .course-languages { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .course-word-grid { grid-template-columns: 1fr; }
  .course-algorithm-words { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .course-algorithm-milestones nav { grid-template-columns: 1fr; }
  .course-milestone-body, .course-algorithm-milestones article { padding: 20px; }
}
@media (max-width: 520px) {
  .course-start-note { padding: 16px; gap: 10px; }
  .course-start-note > span { width: 30px; height: 30px; flex-basis: 30px; font-size: 1rem; }
  .course-language { padding: 10px; gap: 8px; }
  .language-badge { flex-basis: 30px; height: 32px; font-size: .72rem; }
  .course-language b { font-size: .9rem; }
  .course-language small { font-size: .65rem; }
  .course-dictionary-tools { grid-template-columns: 1fr; }
  .learn-sections button, .course-tabs button { padding: 10px 12px; font-size: .78rem; }
  .course-track-brief h2 { font-size: 1.5rem; }
  .course-milestone-nav { grid-template-columns: 1fr; }
  .course-milestone-body, .course-algorithm-definition, .course-algorithm-milestones article { padding: 16px; }
  .course-trace { padding: 16px 12px; }
  .course-trace-numbers { gap: 4px; }
  .course-trace-numbers span { font-size: .9rem; }
  .course-trace-numbers small { font-size: .5rem; }
  .course-trace-values { flex-wrap: wrap; gap: 12px; }
  .course-code pre { padding: 14px 12px; font-size: .72rem; }
  .course-check-actions { flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) {
  .course-language { transition: none; }
  .course-language:hover { transform: none; }
}


/* Course UI color rhythm: blue = learn, coral = build, yellow = checkpoint */
.project-path-intro{
  border-top:5px solid var(--coral);
  background:linear-gradient(120deg,var(--red-soft),var(--panel) 78%);
}
.project-subject-card:nth-child(4n+1){border-top:5px solid var(--blue)}
.project-subject-card:nth-child(4n+2){border-top:5px solid var(--coral)}
.project-subject-card:nth-child(4n+3){border-top:5px solid var(--yellow)}
.project-subject-card:nth-child(4n){border-top:5px solid var(--green)}
.project-code-links a:hover{background:var(--blue-soft)}
.learn-sections button:nth-child(odd){border-color:var(--blue)}
.learn-sections button:nth-child(even){border-color:var(--coral)}
.learn-sections button.active,
.course-tabs button.active,
.course-algorithm-code nav button.active{
  background:var(--blue);
  color:#fff;
}
.course-start-note{
  border-left:5px solid var(--blue);
  background:linear-gradient(110deg,var(--blue-soft),var(--panel) 72%);
}
.course-language:nth-child(3n+1){border-top:4px solid var(--blue)}
.course-language:nth-child(3n+2){border-top:4px solid var(--coral)}
.course-language:nth-child(3n){border-top:4px solid var(--yellow)}
.course-language.active{
  background:var(--blue-soft);
}
.course-track-brief{
  border-top:5px solid var(--blue);
}
.course-word:nth-child(4n+1){border-left:4px solid var(--blue)}
.course-word:nth-child(4n+2){border-left:4px solid var(--coral)}
.course-word:nth-child(4n+3){border-left:4px solid var(--yellow)}
.course-word:nth-child(4n){border-left:4px solid var(--green)}
.course-goal{
  background:var(--blue-soft);
  border-left:4px solid var(--blue);
}
.course-practice{
  background:var(--red-soft);
  border-left:4px solid var(--coral);
}
.course-check{
  border-top:4px solid var(--yellow);
}
.course-done-tag{
  background:var(--green-soft);
}
.course-check-feedback[data-result="correct"]{
  background:var(--green-soft);
  border-left:4px solid var(--green);
}
.course-check-feedback[data-result="retry"]{
  background:var(--red-soft);
  border-left:4px solid var(--coral);
}
.course-next{
  border-color:var(--blue);
}


/* Bubble Sort visualizer: First Comet vintage theme */
.course-bubble-sort{
  margin:0 0 24px;
  padding:22px;
  border:2px solid var(--line);
  border-radius:16px;
  background:var(--paper);
  box-shadow:6px 7px 0 var(--line);
}
.bubble-intro{
  display:grid;
  grid-template-columns:minmax(0,1fr) 240px;
  gap:18px;
  align-items:end;
  margin-bottom:18px;
}
.bubble-intro h3{
  margin:5px 0 8px;
  font-size:1.45rem;
}
.bubble-intro p{
  margin:0;
  max-width:760px;
  color:var(--muted);
  font-size:.95rem;
  line-height:1.65;
}
.bubble-rule{
  display:grid;
  gap:5px;
  padding:13px;
  border:2px solid var(--line);
  border-radius:11px;
  background:var(--yellow);
  color:#171319;
  box-shadow:3px 3px 0 var(--line);
}
.bubble-rule b{
  font-size:.86rem;
}
.bubble-rule span{
  font-size:.78rem;
  line-height:1.4;
}

#bubbleSortDemo{
  display:grid;
  gap:14px;
}
.bubble-visual{
  display:grid;
  grid-template-columns:repeat(6,minmax(58px,1fr));
  gap:12px;
  align-items:end;
  min-height:230px;
  padding:24px 18px 16px;
  border:2px solid var(--line);
  border-radius:13px;
  background:var(--cream);
  overflow:hidden;
}
.bubble-item{
  position:relative;
  display:grid;
  grid-template-rows:auto var(--bubble-height) 20px;
  gap:6px;
  align-items:end;
  min-width:0;
  text-align:center;
}
.bubble-item>span{
  display:grid;
  place-items:center;
  width:38px;
  height:38px;
  margin:0 auto;
  border:2px solid var(--line);
  border-radius:50%;
  background:var(--panel);
  color:var(--ink);
  box-shadow:2px 2px 0 var(--line);
  font:700 1rem "DM Mono",monospace;
  z-index:2;
}
.bubble-item>i{
  display:block;
  align-self:end;
  width:100%;
  height:var(--bubble-height);
  border:2px solid var(--line);
  border-radius:8px 8px 3px 3px;
  background:var(--blue);
  box-shadow:3px 3px 0 var(--line);
}
.bubble-item>small{
  min-height:18px;
  color:var(--muted);
  font:700 .66rem "DM Mono",monospace;
  text-transform:uppercase;
  letter-spacing:.06em;
}
.bubble-item.comparing>span{
  background:var(--yellow);
  color:#171319;
}
.bubble-item.comparing>i{
  background:var(--coral);
}
.bubble-item.sorted>span{
  background:var(--green-soft);
}
.bubble-item.sorted>i{
  background:var(--green);
}
.bubble-item.sorted>small{
  color:var(--green);
}
.bubble-item.swap-from-right{
  animation:bubbleArriveFromRight .42s ease both;
}
.bubble-item.swap-from-left{
  animation:bubbleArriveFromLeft .42s ease both;
}
@keyframes bubbleArriveFromRight{
  0%{transform:translateX(108%)}
  100%{transform:translateX(0)}
}
@keyframes bubbleArriveFromLeft{
  0%{transform:translateX(-108%)}
  100%{transform:translateX(0)}
}

.bubble-status{
  padding:14px 16px;
  border:2px solid var(--line);
  border-left:7px solid var(--blue);
  border-radius:11px;
  background:var(--panel);
}
.bubble-status p{
  margin:5px 0 0;
  font-size:.9rem;
  line-height:1.55;
}
.bubble-controls{
  display:flex;
  flex-wrap:wrap;
  gap:9px;
}
.bubble-controls button{
  min-height:42px;
}
.bubble-controls button:disabled{
  opacity:.5;
  cursor:default;
  box-shadow:none;
}
.bubble-explain{
  margin-top:15px;
  border-top:2px solid var(--line);
}
.bubble-explain summary{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:10px;
  padding-top:13px;
  cursor:pointer;
  list-style:none;
  font-size:.88rem;
  font-weight:700;
}
.bubble-explain summary::-webkit-details-marker{display:none}
.bubble-explain summary span{
  display:grid;
  place-items:center;
  width:24px;
  height:24px;
  border:1.5px solid var(--line);
  border-radius:50%;
  background:var(--yellow);
  color:#171319;
}
.bubble-explain[open] summary span{
  transform:rotate(45deg);
}
.bubble-explain p{
  margin:10px 0 0;
  color:var(--muted);
  font-size:.86rem;
  line-height:1.65;
}

.dark .course-bubble-sort{
  background:var(--panel);
}
.dark .bubble-visual{
  background:var(--cream);
}
.dark .bubble-item>span,
.dark .bubble-status{
  background:var(--paper);
}
.dark .bubble-item.comparing>span,
.dark .bubble-rule,
.dark .bubble-explain summary span{
  color:#171319;
}

@media(max-width:760px){
  .bubble-intro{
    grid-template-columns:1fr;
  }
  .bubble-rule{
    max-width:none;
  }
  .bubble-visual{
    gap:6px;
    min-height:205px;
    padding:20px 8px 14px;
  }
  .bubble-item{
    grid-template-rows:auto var(--bubble-height) 18px;
  }
  .bubble-item>span{
    width:32px;
    height:32px;
    font-size:.86rem;
  }
  .bubble-item>small{
    font-size:.55rem;
  }
}
@media(max-width:480px){
  .course-bubble-sort{
    padding:15px 12px;
  }
  .bubble-visual{
    grid-template-columns:repeat(6,minmax(40px,1fr));
  }
  .bubble-item>span{
    width:28px;
    height:28px;
    font-size:.76rem;
  }
  .bubble-item>small{
    font-size:.48rem;
  }
  .bubble-controls{
    display:grid;
    grid-template-columns:1fr;
  }
  .bubble-controls button{
    width:100%;
  }
}
@media(prefers-reduced-motion:reduce){
  .bubble-item.swap-from-right,
  .bubble-item.swap-from-left{
    animation:none!important;
  }
}


/* Bubble Sort short-style controls */
.bubble-speed{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:7px;
  padding:10px 12px;
  border:1.5px solid var(--line);
  border-radius:10px;
  background:var(--panel);
}
.bubble-speed>span{
  margin-right:3px;
  font:700 .72rem "DM Mono",monospace;
  text-transform:uppercase;
  letter-spacing:.07em;
}
.bubble-speed button{
  min-height:32px;
  padding:6px 10px;
  border:1.5px solid var(--line);
  border-radius:8px;
  background:var(--paper);
  color:var(--ink);
  cursor:pointer;
  font-size:.76rem;
  font-weight:700;
}
.bubble-speed button.active{
  background:var(--yellow);
  color:#171319;
  box-shadow:2px 2px 0 var(--line);
}
.bubble-speed small{
  margin-left:auto;
  color:var(--muted);
  font-size:.72rem;
}
.bubble-controls [data-bubble-random]{
  border-color:var(--blue);
}

/* Make compare/swap states read instantly like an animation short */
.bubble-item.comparing{
  z-index:3;
}
.bubble-item.comparing>span{
  transform:translateY(-4px);
  box-shadow:3px 4px 0 var(--line);
}
.bubble-item.comparing>i{
  box-shadow:4px 5px 0 var(--line);
}
.bubble-item.sorted{
  opacity:.9;
}
.bubble-item.sorted>span:after{
  content:"✓";
  position:absolute;
  right:-5px;
  top:-7px;
  display:grid;
  place-items:center;
  width:17px;
  height:17px;
  border:1.5px solid var(--line);
  border-radius:50%;
  background:var(--yellow);
  color:#171319;
  font-size:.6rem;
}
.bubble-item>span{
  position:relative;
  transition:transform .2s ease,background .2s ease,box-shadow .2s ease;
}
.bubble-item>i{
  transition:background .2s ease,box-shadow .2s ease;
}

@media(max-width:600px){
  .bubble-speed{
    display:grid;
    grid-template-columns:auto repeat(3,1fr);
  }
  .bubble-speed small{
    grid-column:1/-1;
    margin-left:0;
  }
}
@media(prefers-reduced-motion:reduce){
  .bubble-item>span,
  .bubble-item>i{
    transition:none!important;
  }
}


/* Learn page responsive-fit pass
   The workspace rail + main padding reduce usable width long before the
   viewport itself reaches the old 1050px breakpoint. */
#view-learn,
#view-learn .learn-section,
#view-learn #courseApp,
#view-learn #courseTabContent{
  min-width:0;
  max-width:100%;
}
#view-learn .course-milestone-layout,
#view-learn .course-milestone-body,
#view-learn .course-track-brief,
#view-learn .course-start-note,
#view-learn .course-algorithm-milestones,
#view-learn .course-bubble-sort,
#view-learn .course-trace,
#view-learn .course-algorithm-definition{
  min-width:0;
  max-width:100%;
}
#view-learn .course-code,
#view-learn .course-table-scroll{
  max-width:100%;
}
#view-learn .course-code pre{
  max-width:100%;
  overflow-x:auto;
}

/* A normal 1280-1440px laptop has only about 950-1100px left for the
   course after the rail and page gutters. Reflow before it clips. */
@media (max-width: 1450px){
  body:has(#view-learn.active) main{
    padding-left:28px;
    padding-right:28px;
  }
  #view-learn .course-milestone-layout,
  #view-learn .course-algorithm-milestones{
    grid-template-columns:1fr;
  }
  #view-learn .course-milestone-nav{
    grid-template-columns:repeat(4,minmax(0,1fr));
  }
  #view-learn .course-algorithm-milestones nav{
    grid-template-columns:repeat(3,minmax(0,1fr));
  }
  #view-learn .course-milestone-nav button{
    min-width:0;
  }
  #view-learn .course-milestone-nav b,
  #view-learn .course-milestone-nav small{
    overflow-wrap:anywhere;
  }
}

/* Medium desktop / high browser zoom */
@media (max-width: 1250px){
  body:has(#view-learn.active) main{
    padding-left:22px;
    padding-right:22px;
  }
  #view-learn .course-languages{
    grid-template-columns:repeat(2,minmax(0,1fr));
  }
  #view-learn .course-track-brief{
    grid-template-columns:minmax(0,1fr) 220px;
    gap:18px;
    padding:20px;
  }
  #view-learn .course-milestone-nav{
    grid-template-columns:repeat(2,minmax(0,1fr));
  }
  #view-learn .course-milestone-body,
  #view-learn .course-algorithm-milestones article{
    padding:22px;
  }
}

/* Narrow desktop/tablet: everything becomes a single readable flow. */
@media (max-width: 1080px){
  #view-learn .course-track-brief,
  #view-learn .course-dictionary-tools{
    grid-template-columns:1fr;
  }
  #view-learn .course-track-progress{
    max-width:none;
  }
  #view-learn .course-algorithm-words{
    grid-template-columns:repeat(2,minmax(0,1fr));
  }
  #view-learn .course-panel-head{
    display:block;
  }
}

/* Tables may scroll inside their own frame, but the whole page must not. */
#view-learn .course-table-scroll{
  overflow-x:auto;
  overscroll-behavior-inline:contain;
}
#view-learn .course-compare-table{
  width:max-content;
  max-width:none;
}
#view-learn .course-role-table table{
  max-width:none;
}

/* Never let long code/URLs force the workspace wider. */
#view-learn p,
#view-learn li,
#view-learn dd,
#view-learn small,
#view-learn a,
#view-learn code{
  overflow-wrap:anywhere;
}

/* At laptop heights, avoid wasting a large amount of vertical space above
   the current lesson. */
@media (min-width: 761px) and (max-height: 850px){
  #view-learn .course-page-heading{
    margin-bottom:8px;
  }
  #view-learn .course-page-heading h1{
    margin-top:5px;
    margin-bottom:7px;
  }
  #view-learn .learn-sections{
    margin:14px 0;
  }
  #view-learn .course-start-note{
    padding:14px 16px;
    margin-bottom:14px;
  }
  #view-learn .course-languages{
    margin:14px 0;
  }
  #view-learn .course-track-brief{
    margin:16px 0;
  }
  #view-learn .course-panel-head{
    margin:20px 0 14px;
  }
}


/* Compact Learn section selector */
.learn-section-picker{
  position:relative;
  width:min(100%,300px);
  margin:24px 0;
  display:grid;
  gap:6px;
}
.learn-section-picker label{
  color:var(--muted);
  font:800 .68rem "DM Mono",monospace;
  letter-spacing:.08em;
  text-transform:uppercase;
}
.learn-section-picker:after{
  content:'▾';
  position:absolute;
  right:7px;
  bottom:7px;
  display:grid;
  place-items:center;
  width:28px;
  height:28px;
  border:1.5px solid var(--line);
  border-radius:7px;
  background:var(--yellow);
  color:#171319;
  box-shadow:1px 1px 0 var(--line);
  pointer-events:none;
  font-weight:900;
}
#learnSectionSelect{
  appearance:none;
  -webkit-appearance:none;
  width:100%;
  min-height:44px;
  padding:10px 44px 10px 12px;
  border:2px solid var(--line);
  border-radius:10px;
  background:var(--panel);
  color:var(--ink);
  box-shadow:3px 3px 0 var(--line);
  cursor:pointer;
  font-weight:800;
}
#learnSectionSelect:hover,
#learnSectionSelect:focus{
  outline:0;
  background:var(--yellow-soft);
  box-shadow:4px 4px 0 var(--line);
}
#learnSectionSelect option{
  background:var(--panel);
  color:var(--ink);
}


/* Focused Learn home */
.learn-start-home{
  max-width:920px;
  margin:18px auto 0;
}
.learn-focus-card{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:28px;
  align-items:center;
  padding:28px;
  border:2px solid var(--line);
  border-top:6px solid var(--blue);
  border-radius:16px;
  background:var(--panel);
  box-shadow:6px 6px 0 var(--line);
}
.learn-focus-copy h2{
  margin:8px 0 10px;
  max-width:680px;
  font-size:clamp(1.65rem,3vw,2.45rem);
  line-height:1.08;
  letter-spacing:-.035em;
}
.learn-focus-copy p{
  max-width:650px;
  margin:0;
  color:var(--muted);
  font-size:.95rem;
  line-height:1.6;
}
.learn-focus-action{
  min-width:190px;
  min-height:48px;
  align-self:center;
}
.learn-path-preview{
  display:flex;
  align-items:center;
  justify-content:center;
  gap:10px;
  margin:24px auto 14px;
  color:var(--muted);
  font:700 .72rem "DM Mono",monospace;
}
.learn-path-preview button{
  display:inline-flex;
  align-items:center;
  gap:7px;
  padding:7px 10px;
  border:1.5px solid var(--line);
  border-radius:999px;
  background:var(--panel);
  color:var(--muted);
  cursor:pointer;
}
.learn-path-preview button:hover,
.learn-path-preview button:focus-visible{
  color:var(--ink);
  background:var(--blue-soft);
  box-shadow:2px 2px 0 var(--line);
  outline:0;
}
.learn-path-preview button.active{
  background:var(--yellow-soft);
  color:var(--ink);
  box-shadow:2px 2px 0 var(--line);
}
.learn-path-preview button b{
  font-family:"Space Grotesk",system-ui,sans-serif;
  font-size:.78rem;
}
.learn-path-preview i{
  color:var(--muted);
  font-style:normal;
}
.learn-more-options{
  width:min(100%,700px);
  margin:14px auto 0;
}
.learn-more-options>summary{
  width:max-content;
  margin:0 auto;
  padding:7px 10px;
  border:1.5px solid var(--line);
  border-radius:8px;
  background:var(--panel);
  color:var(--muted);
  box-shadow:2px 2px 0 var(--line);
  cursor:pointer;
  font-size:.74rem;
  font-weight:800;
  list-style:none;
}
.learn-more-options>summary::-webkit-details-marker{display:none}
.learn-more-options>summary:after{
  content:' +';
  color:var(--coral);
  font-weight:900;
}
.learn-more-options[open]>summary{
  color:var(--ink);
  background:var(--cream);
}
.learn-more-options[open]>summary:after{content:' -'}
.learn-more-grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:10px;
  margin-top:12px;
  padding:12px;
  border:1.5px solid var(--line);
  border-radius:12px;
  background:var(--paper);
}
.learn-more-grid button{
  display:grid;
  gap:4px;
  min-height:78px;
  padding:12px;
  border:1.5px solid var(--line);
  border-radius:10px;
  background:var(--panel);
  color:var(--ink);
  text-align:left;
  cursor:pointer;
}
.learn-more-grid button:hover,
.learn-more-grid button:focus-visible{
  background:var(--blue-soft);
  box-shadow:2px 2px 0 var(--line);
  outline:0;
}
.learn-more-grid button b{
  font-size:.84rem;
}
.learn-more-grid button small{
  color:var(--muted);
  font-size:.7rem;
  line-height:1.4;
}
.learn-back-home{
  margin:4px 0 18px;
  padding:7px 10px;
  border:1.5px solid var(--line);
  border-radius:8px;
  background:var(--panel);
  color:var(--muted);
  cursor:pointer;
  font-size:.72rem;
  font-weight:800;
}
.learn-back-home:hover,
.learn-back-home:focus-visible{
  color:var(--ink);
  background:var(--cream);
  outline:0;
}
.dark .learn-focus-card,
.dark .learn-more-grid,
.dark .learn-more-grid button,
.dark .learn-more-options>summary,
.dark .learn-back-home{
  background:var(--panel);
  color:var(--ink);
}
@media(max-width:760px){
  .learn-focus-card{
    grid-template-columns:1fr;
    gap:18px;
    padding:20px;
  }
  .learn-focus-action{
    width:100%;
  }
  .learn-path-preview{
    gap:6px;
  }
  .learn-path-preview button{
    padding:6px 8px;
  }
}
@media(max-width:560px){
  .learn-more-grid{
    grid-template-columns:1fr;
  }
  .learn-path-preview button b{
    display:none;
  }
}