:root {
  font-family:
    Inter,
    ui-sans-serif,
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    sans-serif;
  color: #e9eef7;
  background: #0c1220;
  font-size: 16px;
  color-scheme: dark;
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
}
button,
input {
  font: inherit;
}
button {
  cursor: pointer;
}
button:focus-visible,
input:focus-visible,
a:focus-visible,
summary:focus-visible {
  outline: 3px solid #7ff2cf;
  outline-offset: 4px;
}
button:disabled {
  cursor: default;
}
a {
  color: #86eacd;
}
.shell {
  max-width: 1320px;
  margin: auto;
  padding: 0 28px;
}
.top {
  border-bottom: 1px solid #29394d;
  background: #10192a;
}
.top .shell {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand {
  font-size: 1.18rem;
  font-weight: 800;
  letter-spacing: -0.035em;
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: #eef7ff;
}
.brandmark {
  display: grid;
  place-items: center;
  background: #5be7bc;
  color: #101827;
  border-radius: 11px;
  width: 36px;
  height: 36px;
  flex-shrink: 0;
  font-weight: 900;
}
.c-badge {
  border: 1px solid #37596a;
  color: #80e3c4;
  padding: 5px 8px;
  border-radius: 6px;
  font-size: 0.8rem;
  letter-spacing: 0;
  white-space: nowrap;
}
.top-note {
  color: #a7bad0;
  font-size: 0.9rem;
}
.intro {
  padding: 34px 0 28px;
}
.eyebrow {
  color: #65eac1;
  text-transform: uppercase;
  font-weight: 800;
  letter-spacing: 0.13em;
  font-size: 0.78rem;
}
.intro h1 {
  font-size: clamp(1.8rem, 4vw, 2.55rem);
  letter-spacing: -0.05em;
  line-height: 1.15;
  margin: 12px 0;
}
.intro p {
  color: #b8c7da;
  line-height: 1.6;
  margin: 0;
}
.workspace {
  display: grid;
  grid-template-columns: 285px minmax(0, 1fr);
  gap: 24px;
}
.sidebar,
.lesson {
  border: 1px solid #29384e;
  background: #131e30;
  border-radius: 18px;
}
.sidebar {
  padding: 20px;
  align-self: start;
}
.sidebar h2 {
  font-size: 1rem;
  margin: 0 0 17px;
}
.levels {
  display: flex;
  gap: 6px;
}
.level {
  border: 1px solid #3a4e68;
  background: #1c2a40;
  color: #c4d2e4;
  border-radius: 8px;
  padding: 10px 7px;
  font-weight: 700;
  font-size: 0.8rem;
  flex: 1;
}
.level.active {
  background: #5be7bc;
  border-color: #5be7bc;
  color: #0e1a25;
}
.level-help {
  font-size: 0.88rem;
  color: #adc1d8;
  line-height: 1.5;
  margin: 14px 0;
}
.lesson-list {
  display: grid;
  gap: 5px;
}
.lesson-link {
  display: flex;
  width: 100%;
  text-align: left;
  align-items: flex-start;
  gap: 10px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 10px;
  color: #d6e2f1;
  padding: 11px 7px;
  line-height: 1.45;
}
.lesson-link:hover,
.lesson-link.active {
  background: #22334c;
  border-color: #426183;
}
.number {
  display: grid;
  place-items: center;
  flex: none;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: #2c4059;
  color: #9ff0d4;
  font-size: 0.8rem;
  font-weight: 800;
}
.lesson-link strong {
  display: block;
  font-size: 0.88rem;
  font-weight: 650;
}
.lesson-link small {
  display: block;
  color: #a5bad1;
  margin-top: 3px;
  font-size: 0.78rem;
}
.progress-area {
  border-top: 1px solid #304257;
  margin-top: 22px;
  padding-top: 18px;
  font-size: 0.85rem;
  color: #cbdaeb;
}
.progress-area small {
  display: block;
  font-size: 0.76rem;
  color: #a5b6ca;
  line-height: 1.5;
}
progress {
  width: 100%;
  height: 7px;
  margin: 12px 0;
  accent-color: #62e4bc;
}
progress::-webkit-progress-bar {
  background: #31445c;
  border-radius: 10px;
}
progress::-webkit-progress-value {
  background: #62e4bc;
  border-radius: 10px;
}
.lesson {
  padding: clamp(20px, 3.5vw, 38px);
  min-width: 0;
  align-self: start;
}
.lesson-meta {
  display: flex;
  gap: 14px;
  align-items: center;
  font-size: 0.86rem;
  color: #b0c1d5;
  flex-wrap: wrap;
}
.pill {
  padding: 5px 12px;
  border-radius: 100px;
  color: #72e9c5;
  background: #183c3c;
}
.lesson h2 {
  font-size: clamp(1.65rem, 3.5vw, 2.3rem);
  line-height: 1.2;
  letter-spacing: -0.04em;
  margin: 17px 0 10px;
  overflow-wrap: anywhere;
}
.goal {
  color: #b9cde0;
  line-height: 1.55;
  margin: 0;
}
.stages {
  display: flex;
  gap: 6px;
  border-bottom: 1px solid #334960;
  margin: 26px 0;
}
.stage {
  background: transparent;
  border: 0;
  border-bottom: 3px solid transparent;
  color: #aabdd4;
  padding: 13px 9px;
  font-weight: 750;
  font-size: 0.92rem;
}
.stage.active {
  border-color: #5be7bc;
  color: #85efce;
}
#content h3 {
  font-size: 1.15rem;
  margin: 25px 0 8px;
}
#content p {
  line-height: 1.75;
  color: #cad7e7;
  margin: 8px 0 16px;
}
#content .lead {
  font-size: 1.1rem;
  color: #e0eaf6;
}
.learn-block {
  padding-left: 18px;
  border-left: 2px solid #34536c;
  margin: 24px 0;
}
.learn-block h3 {
  margin-top: 0 !important;
}
.callout {
  border-left: 3px solid #5be7bc;
  background: #1a3041;
  padding: 15px 18px;
  color: #d7eaec;
  line-height: 1.65;
  border-radius: 0 9px 9px 0;
  margin: 24px 0;
}
.action,
.secondary {
  border: 0;
  border-radius: 9px;
  background: #5be7bc;
  color: #0c1d25;
  font-weight: 800;
  padding: 12px 18px;
  line-height: 1.5;
}
.action:disabled {
  opacity: 0.5;
}
.secondary {
  background: #243950;
  color: #d9e9f8;
  border: 1px solid #486481;
}
.actions {
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
  margin-top: 20px;
}
.muted {
  color: #acc0d6;
  font-size: 0.9rem;
  line-height: 1.6;
}
.code-box {
  background: #0a1321;
  border: 1px solid #3a536b;
  border-radius: 12px;
  overflow: hidden;
}
.code-toolbar {
  padding: 12px 16px;
  border-bottom: 1px solid #2b4057;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  color: #b5c9df;
  font-size: 0.85rem;
}
.code-toolbar button {
  background: transparent;
  border: 1px solid #45617d;
  color: #cae3f2;
  border-radius: 6px;
  padding: 6px 10px;
  font-size: 0.85rem;
}
.code-scroll {
  overflow-x: auto;
  padding: 10px 0;
}
.code-line {
  display: flex;
  align-items: baseline;
  text-align: left;
  width: 100%;
  min-width: max-content;
  background: transparent;
  border: 0;
  border-left: 3px solid transparent;
  color: #e2eefb;
  font:
    500 0.92rem/1.85 ui-monospace,
    SFMono-Regular,
    Consolas,
    monospace;
  padding: 3px 14px 3px 0;
  white-space: pre;
}
.code-line:hover {
  background: #20334a;
}
.code-line.selected {
  background: #213d4c;
  border-left-color: #71e8c2;
}
.line-no {
  width: 44px;
  flex-shrink: 0;
  text-align: right;
  padding-right: 15px;
  color: #93abc1;
  user-select: none;
  font-size: 0.8rem;
}
.code-line.path-yes {
  box-shadow: inset 5px 0 #5fd7ba;
}
.code-line.path-no {
  box-shadow: inset 5px 0 #d8b981;
}
.code-line.path-after {
  box-shadow: inset 5px 0 #8ebafa;
}
.line-note {
  margin-top: 12px;
  background: #20354a;
  border-radius: 10px;
  padding: 16px 18px;
  line-height: 1.65;
  color: #dfedf8;
  min-height: 92px;
}
.line-note strong {
  color: #82eccc;
  display: block;
  margin-bottom: 5px;
}
.legend {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin: 12px 0;
  color: #c0d3e6;
  font-size: 0.8rem;
}
.legend span {
  border-left: 4px solid #5fd7ba;
  padding-left: 8px;
}
.legend span:nth-child(2) {
  border-color: #d8b981;
}
.legend span:nth-child(3) {
  border-color: #8ebafa;
}
.lab {
  margin-top: 22px;
  background: #18283e;
  border: 1px solid #3b526c;
  border-radius: 12px;
  padding: 20px;
}
.lab h3 {
  margin-top: 0 !important;
}
.lab label {
  display: block;
  font-weight: 700;
  margin: 16px 0 8px;
}
.lab input {
  background: #0e192a;
  border: 1px solid #637e98;
  color: #fff;
  padding: 12px;
  border-radius: 8px;
  width: 100%;
  max-width: 270px;
}
.lab .actions {
  margin-top: 15px;
}
.terminal {
  background: #091521;
  border: 1px solid #39586b;
  border-radius: 8px;
  padding: 16px;
  margin: 15px 0 0;
  color: #8ef1ce;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  font:
    0.95rem/1.7 ui-monospace,
    Consolas,
    monospace;
  min-height: 65px;
}
.lab-status {
  color: #d4e4f4;
  line-height: 1.65;
  margin-top: 15px;
}
.symbol-guide {
  border: 1px solid #3b526c;
  border-radius: 10px;
  margin-top: 22px;
  padding: 15px;
}
.symbol-guide summary {
  cursor: pointer;
  font-weight: 700;
  line-height: 1.5;
}
.symbols {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 16px 0;
}
.symbol {
  font-family: ui-monospace, monospace;
  border: 1px solid #58728e;
  background: #223850;
  color: #e3f5ff;
  border-radius: 7px;
  padding: 8px 12px;
  min-width: 46px;
}
.symbol[aria-pressed="true"] {
  border-color: #74eac5;
  color: #85f0cd;
}
.symbol-description {
  line-height: 1.65;
  color: #cdddea;
}
.question-count {
  color: #7fe4c4;
  font-size: 0.86rem;
  font-weight: 800;
  letter-spacing: 0.04em;
}
.options {
  display: grid;
  gap: 10px;
  margin: 22px 0 17px;
}
.option {
  display: flex;
  gap: 12px;
  align-items: baseline;
  width: 100%;
  text-align: left;
  border: 1px solid #415977;
  background: #1b2a3f;
  color: #e4eefb;
  border-radius: 10px;
  padding: 14px 16px;
  line-height: 1.6;
}
.option:hover:not(:disabled) {
  border-color: #68eac5;
}
.option.selected {
  border-color: #73e2c0;
  background: #203e42;
}
.option.correct {
  border-color: #69dcb3;
  background: #193e38;
}
.option.wrong {
  border-color: #eeaaa1;
  background: #452d3a;
}
.option-letter {
  color: #9eb7d0;
  font-size: 0.85rem;
  font-weight: 800;
}
.feedback {
  margin: 18px 0;
  padding: 18px;
  border-radius: 10px;
  line-height: 1.65;
  background: #20354a;
  border: 1px solid #56758f;
}
.feedback.good {
  background: #173b38;
  border-color: #62b896;
}
.feedback.bad {
  background: #422d3b;
  border-color: #cf9493;
}
.feedback strong {
  display: block;
}
.feedback p {
  margin: 7px 0 0 !important;
  color: #e3ebf4 !important;
}
.hint {
  color: #d4e4ee;
  border-left: 3px solid #cdb47d;
  padding: 12px 16px;
  background: #30364a;
  margin: 15px 0;
  line-height: 1.6;
}
.lesson-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  border-top: 1px solid #35475d;
  margin-top: 32px;
  padding-top: 22px;
}
.text-button {
  border: 0;
  background: transparent;
  color: #a3e6d3;
  font-weight: 700;
  font-size: 0.9rem;
  padding: 8px 0;
}
.success-mark {
  font-size: 2rem;
  color: #83edc7;
}
footer {
  padding: 28px 0 40px;
  color: #97b0c9;
  font-size: 0.82rem;
  line-height: 1.7;
}
footer a {
  display: inline;
}
code {
  font-family: ui-monospace, monospace;
}
@media (max-width: 900px) {
  .workspace {
    grid-template-columns: 1fr;
  }
  .sidebar {
    padding: 17px;
  }
  .lesson-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .progress-area {
    margin-top: 16px;
  }
  .top-note {
    display: none;
  }
  .intro {
    padding: 28px 0 23px;
  }
  .sidebar h2 {
    margin-bottom: 12px;
  }
  .levels {
    max-width: 440px;
  }
  .lesson {
    padding: 24px;
  }
}
@media (max-width: 520px) {
  .shell {
    padding: 0 15px;
  }
  .brand {
    font-size: 1rem;
    gap: 8px;
  }
  .c-badge {
    font-size: 0.72rem;
  }
  .brandmark {
    width: 31px;
    height: 31px;
  }
  .lesson-list {
    grid-template-columns: 1fr;
    max-height: 244px;
    overflow-y: auto;
  }
  .lesson {
    padding: 20px 16px;
  }
  .stage {
    font-size: 0.83rem;
    padding: 11px 7px;
  }
  .intro h1 {
    font-size: 1.95rem;
  }
  .lab {
    padding: 16px;
  }
  .code-line {
    font-size: 0.85rem;
  }
  .line-no {
    width: 33px;
    padding-right: 10px;
  }
  .actions button {
    flex-grow: 1;
  }
  .code-toolbar {
    padding: 10px;
    flex-wrap: wrap;
  }
}
@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto !important;
  }
}
[hidden] {
  display: none !important;
}
.view-enter {
  animation: view-enter 0.42s ease both;
}
.reveal-stagger > * {
  animation: content-reveal 0.48s ease both;
}
.reveal-stagger > *:nth-child(2) {
  animation-delay: 0.06s;
}
.reveal-stagger > *:nth-child(3) {
  animation-delay: 0.12s;
}
.reveal-stagger > *:nth-child(4) {
  animation-delay: 0.18s;
}
@keyframes view-enter {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
@keyframes content-reveal {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
.app-nav {
  display: flex;
  gap: 6px;
  margin: 0 0 24px;
  border-bottom: 1px solid #34485f;
}
.app-nav button {
  padding: 14px 20px;
  background: transparent;
  color: #a8bed6;
  border: 0;
  border-bottom: 3px solid transparent;
  font-weight: 750;
  font-size: 1rem;
}
.app-nav button[aria-current="page"] {
  color: #88efcd;
  border-bottom-color: #5be7bc;
}
.app-nav button:hover {
  background: #192a3e;
}
.section-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  margin: 8px 0 26px;
}
.section-heading h2 {
  font-size: clamp(1.6rem, 3vw, 2.1rem);
  letter-spacing: -0.04em;
  line-height: 1.2;
  margin: 10px 0;
}
.section-heading p {
  color: #b7cbe1;
  line-height: 1.65;
  max-width: 730px;
}
.counter {
  color: #91e9c9;
  background: #173938;
  padding: 10px 14px;
  border-radius: 9px;
  font-size: 0.88rem;
  line-height: 1.6;
}
.exercise-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 23px;
}
.exercise-filters button {
  background: #1c2d44;
  color: #c7d8eb;
  border: 1px solid #47617a;
  border-radius: 20px;
  padding: 9px 16px;
  font-size: 0.9rem;
}
.exercise-filters button[aria-pressed="true"] {
  background: #5be7bc;
  color: #0c1d25;
  border-color: #5be7bc;
  font-weight: 700;
}
.exercise-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}
.exercise-card {
  border: 1px solid #344c65;
  background: #131f32;
  border-radius: 14px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}
.exercise-meta {
  color: #91e1c9;
  font-size: 0.82rem;
  line-height: 1.5;
}
.exercise-card h3 {
  font-size: 1.24rem;
  line-height: 1.3;
  margin: 15px 0 10px;
}
.exercise-card p {
  line-height: 1.7;
  color: #bcd0e5;
  margin: 0 0 22px;
  flex: 1;
}
.exercise-card button {
  font-size: 0.9rem;
}
.coding-layout {
  display: grid;
  grid-template-columns: minmax(250px, 320px) minmax(0, 1fr);
  gap: 24px;
}
.coding-instructions {
  background: #131f32;
  border: 1px solid #344c65;
  border-radius: 14px;
  padding: 24px;
  align-self: start;
  min-width: 0;
}
.coding-instructions h3 {
  font-size: 1.2rem;
  margin-top: 0;
}
.coding-instructions h4 {
  font-size: 0.9rem;
  margin: 20px 0 8px;
  color: #c4d9ef;
}
.coding-instructions p,
.coding-instructions li {
  color: #c3d4e5;
  line-height: 1.75;
}
.coding-instructions ol {
  padding-left: 20px;
}
.coding-instructions li {
  padding-left: 3px;
  margin-bottom: 12px;
}
.coding-instructions label {
  display: block;
  margin: 20px 0 8px;
  font-weight: 700;
}
.coding-instructions select {
  width: 100%;
  font: inherit;
  padding: 12px 8px;
  background: #0d1929;
  color: #e2edf8;
  border: 1px solid #56728d;
  border-radius: 8px;
  margin-bottom: 12px;
}
.coding-instructions .text-button {
  display: block;
  margin: 10px 0;
}
.coding-instructions details {
  border-top: 1px solid #36516a;
  padding-top: 18px;
  margin-top: 20px;
}
.coding-instructions summary {
  cursor: pointer;
  font-weight: 700;
  line-height: 1.6;
}
.sample {
  font:
    0.92rem/1.65 ui-monospace,
    Consolas,
    monospace;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  background: #0b1627;
  color: #dbf0fd;
  border: 1px solid #324a62;
  border-radius: 8px;
  padding: 12px;
  margin: 0;
}
.compact {
  font-size: 0.88rem;
  padding: 12px;
  margin: 20px 0;
}
.solution-code {
  background: #0b1627;
  color: #dceefd;
  font:
    0.85rem/1.7 ui-monospace,
    Consolas,
    monospace;
  border: 1px solid #3c5369;
  border-radius: 8px;
  padding: 12px;
  overflow: auto;
  max-height: 350px;
}
.runtime-help {
  font-size: 0.88rem;
}
.coding-workspace {
  min-width: 0;
}
.editor-card,
.result-card {
  background: #132135;
  border: 1px solid #3c5671;
  border-radius: 14px;
  overflow: hidden;
}
.editor-toolbar {
  background: #1d3149;
  padding: 14px 18px;
  display: flex;
  gap: 16px;
  justify-content: space-between;
  align-items: center;
}
.editor-toolbar label {
  font-weight: 700;
  font-size: 0.94rem;
}
.editor-toolbar span {
  color: #a8c1d8;
  font-size: 0.8rem;
}
textarea {
  font: inherit;
}
#cCode {
  width: 100%;
  min-height: 380px;
  resize: vertical;
  display: block;
  border: 0;
  background: #091525;
  color: #e1f4ff;
  padding: 20px;
  font:
    1rem/1.75 ui-monospace,
    SFMono-Regular,
    Consolas,
    monospace;
  tab-size: 4;
  border-radius: 0;
  white-space: pre;
  overflow: auto;
}
#cCode:focus {
  outline: 2px solid #72dec0;
  outline-offset: -2px;
}
textarea:focus-visible,
select:focus-visible {
  outline: 3px solid #74e6c4;
  outline-offset: 2px;
}
.editor-help {
  padding: 0 18px;
  font-size: 0.82rem;
  line-height: 1.65;
}
.input-area {
  border-top: 1px solid #344d65;
  padding: 18px;
}
.input-area label {
  font-weight: 700;
  display: block;
  margin-bottom: 10px;
}
.input-area textarea {
  width: 100%;
  resize: vertical;
  background: #0b192a;
  color: #def0ff;
  border: 1px solid #526f8d;
  border-radius: 8px;
  padding: 12px;
  font:
    1rem/1.65 ui-monospace,
    Consolas,
    monospace;
}
.input-area p {
  font-size: 0.82rem;
  margin: 8px 0 0;
}
.run-actions {
  padding: 0 18px 18px;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}
.run-actions span {
  color: #b9d0e6;
  font-size: 0.86rem;
}
.stop-button {
  padding: 11px 16px;
  background: #51303b;
  color: #ffd4cc;
  border: 1px solid #c78989;
  border-radius: 9px;
  font: inherit;
  font-weight: 700;
}
.result-card {
  margin-top: 20px;
  padding: 20px;
}
.result-heading {
  display: flex;
  gap: 15px;
  justify-content: space-between;
  align-items: center;
}
.result-heading h3 {
  font-size: 1.1rem;
  margin: 0;
}
.result-heading span {
  color: #9ce8ce;
  font-size: 0.82rem;
}
.result-card h4 {
  font-size: 0.9rem;
  margin-bottom: 8px;
}
.result-card .feedback {
  font-size: 0.96rem;
  margin-top: 20px;
}
.result-card .feedback p {
  color: #d7e7f5;
  line-height: 1.65;
  margin-bottom: 0;
}
.test-case {
  border: 1px solid #41617d;
  border-radius: 9px;
  padding: 14px;
  margin-top: 12px;
}
.test-case summary {
  cursor: pointer;
  font-weight: 700;
  line-height: 1.5;
}
.test-comparison {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}
.test-case p {
  line-height: 1.7;
  color: #c7d9ec;
}
@media (max-width: 1000px) {
  .exercise-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .coding-layout {
    grid-template-columns: 280px minmax(0, 1fr);
  }
  .test-comparison {
    grid-template-columns: 1fr;
  }
}
@media (max-width: 760px) {
  .coding-layout {
    grid-template-columns: 1fr;
  }
  .coding-instructions {
    padding: 20px;
  }
  .section-heading {
    flex-direction: column;
    gap: 5px;
  }
  #cCode {
    min-height: 340px;
  }
  .exercise-grid {
    grid-template-columns: 1fr;
  }
  .app-nav button {
    padding: 12px 13px;
    font-size: 0.93rem;
  }
  .run-actions .action,
  .run-actions .secondary {
    flex: 1;
  }
  .run-actions span {
    width: 100%;
  }
}
@media (prefers-reduced-motion: no-preference) {
  button {
    transition:
      background-color 0.15s,
      border-color 0.15s;
  }
}
.app-nav {
  margin-top: 24px;
}
.app-nav a {
  padding: 14px 20px;
  background: transparent;
  color: #a8bed6;
  border-bottom: 3px solid transparent;
  font-weight: 750;
  font-size: 1rem;
  text-decoration: none;
}
.app-nav a[aria-current="page"] {
  color: #88efcd;
  border-bottom-color: #5be7bc;
}
.app-nav a:hover {
  background: #192a3e;
}
.actions a {
  text-decoration: none;
}
.home-hero {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 65px;
  align-items: center;
  padding: 55px 0 65px;
}
.home-hero h1 {
  font-size: clamp(2.5rem, 5vw, 4.4rem);
  letter-spacing: -0.055em;
  line-height: 1.06;
  margin: 20px 0 24px;
}
.home-hero > div > p {
  font-size: 1.13rem;
  line-height: 1.8;
  color: #c3d4e6;
  max-width: 600px;
}
.home-hero .actions {
  margin-top: 26px;
}
.home-hero .home-footnote {
  font-size: 0.86rem;
  color: #90a9c2;
  margin-top: 22px;
}
.home-code {
  border: 1px solid #46647c;
  border-radius: 16px;
  overflow: hidden;
  background: #0a1525;
  box-shadow: 0 16px 70px #06101b;
}
.home-code pre {
  font:
    1rem/1.9 ui-monospace,
    Consolas,
    monospace;
  padding: 26px 28px;
  margin: 0;
  color: #d5eafb;
  overflow: auto;
}
.code-muted {
  color: #90abc5;
}
.brace-accent {
  color: #83efc9;
  background: #234c47;
  border-radius: 4px;
  padding: 1px 4px;
}
.home-code-note {
  display: flex;
  gap: 17px;
  padding: 19px 24px;
  background: #1a333f;
  border-top: 1px solid #39576b;
  align-items: center;
}
.home-code-note strong {
  font:
    1.7rem ui-monospace,
    Consolas,
    monospace;
  color: #8ff0ce;
  white-space: nowrap;
}
.home-code-note p {
  font-size: 0.95rem;
  line-height: 1.65;
  color: #cfe4e9;
  margin: 0;
}
.home-path {
  padding: 40px 0;
  border-top: 1px solid #2b435a;
}
.home-cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}
.home-card {
  color: #e4effa;
  text-decoration: none;
  border: 1px solid #334f69;
  background: #142238;
  border-radius: 13px;
  padding: 28px;
  display: flex;
  flex-direction: column;
}
.home-card:hover {
  border-color: #70dcb7;
  background: #1a3044;
}
.home-step {
  font:
    0.78rem ui-monospace,
    Consolas,
    monospace;
  color: #90b7cc;
  letter-spacing: 0.06em;
}
.home-card h3 {
  font-size: 1.3rem;
  line-height: 1.3;
  margin: 25px 0 12px;
}
.home-card p {
  color: #bfd0e1;
  line-height: 1.75;
  margin: 0 0 25px;
  flex: 1;
}
.home-card-link {
  font-weight: 750;
  font-size: 0.9rem;
  color: #88ebc6;
}
.home-about {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: 65px;
  border-top: 1px solid #2b435a;
  margin-top: 30px;
  padding: 40px 0;
}
.home-about h2 {
  font-size: 2rem;
  letter-spacing: -0.04em;
  line-height: 1.2;
  max-width: 350px;
}
.home-about p {
  color: #bfd1e3;
  line-height: 1.8;
}
.home-about p:first-child {
  margin-top: 0;
}
.home-hero > div,
.home-about > div,
.home-feedback > div {
  min-width: 0;
}
#homeView .eyebrow,
#homeView .home-step {
  font-size: 0.875rem;
}
#homeView [id] {
  scroll-margin-top: 24px;
}
.teacher-note {
  border-left: 4px solid #79d8f7;
  background: #162a3e;
  padding: 25px 30px;
  border-radius: 0 12px 12px 0;
}
.teacher-note .eyebrow {
  color: #92dfff;
}
.teacher-note h2 {
  margin: 10px 0;
  font-size: 1.4rem;
  line-height: 1.35;
}
.teacher-note p {
  color: #c9daeb;
  line-height: 1.8;
  margin: 0;
  max-width: 1000px;
}
.home-shortcuts {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 25px;
  margin: 22px 0;
}
.home-shortcuts a {
  padding: 10px 0;
  text-underline-offset: 5px;
}
.course-steps {
  list-style: none;
  padding: 0;
  margin: 25px 0;
  border-top: 1px solid #2b435a;
}
.course-steps li {
  padding: 16px 0;
  border-bottom: 1px solid #2b435a;
}
.course-steps strong,
.course-steps span {
  display: block;
  line-height: 1.65;
}
.course-steps span {
  color: #bfd1e3;
  margin-top: 4px;
}
.material-reference {
  background: #142238;
  border: 1px solid #334f69;
  border-radius: 12px;
  margin-top: 26px;
  padding: 25px;
}
.material-reference h3 {
  font-size: 1.2rem;
  line-height: 1.4;
  margin: 12px 0 8px;
}
.material-reference p:last-child {
  margin-bottom: 0;
}
.home-feedback {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 50px;
  padding: 36px;
  margin: 30px 0 45px;
  background: #122b31;
  border: 1px solid #375e66;
  border-radius: 16px;
}
.home-feedback h2 {
  font-size: clamp(1.65rem, 3vw, 2.1rem);
  line-height: 1.25;
  letter-spacing: -0.035em;
  margin: 16px 0;
}
.home-feedback p,
.home-feedback li {
  color: #c6dcdf;
  line-height: 1.8;
}
.home-feedback .feedback-contact {
  border-top: 1px solid #375e66;
  margin-top: 25px;
  padding-top: 20px;
}
.feedback-guide h3 {
  margin-top: 0;
  font-size: 1.15rem;
}
.feedback-guide ul {
  padding-left: 22px;
}
.feedback-guide li + li {
  margin-top: 10px;
}
.home-feedback p:last-child {
  margin-bottom: 0;
}
@media (max-width: 700px) {
  .home-feedback {
    grid-template-columns: 1fr;
    padding: 24px;
    gap: 28px;
  }
  .teacher-note {
    padding: 22px;
  }
  .home-shortcuts {
    gap: 4px 20px;
  }
}
@media (max-width: 900px) {
  .home-hero {
    gap: 25px;
    padding: 35px 0 45px;
  }
  .home-cards {
    gap: 12px;
  }
  .home-card {
    padding: 22px;
  }
  .home-about {
    gap: 30px;
  }
  .home-code pre {
    font-size: 0.87rem;
    padding: 20px;
  }
}
@media (max-width: 700px) {
  .home-hero,
  .home-about {
    grid-template-columns: 1fr;
  }
  .home-hero h1 {
    font-size: 2.9rem;
  }
  .home-code {
    margin-top: 10px;
  }
  .home-cards {
    grid-template-columns: 1fr;
  }
  .home-card h3 {
    margin-top: 18px;
  }
  .home-about {
    gap: 10px;
  }
  .app-nav {
    gap: 0;
    overflow: auto;
  }
  .app-nav a {
    font-size: 0.85rem;
    padding: 12px 10px;
    white-space: nowrap;
  }
  .home-hero .actions a {
    flex: 1;
    text-align: center;
  }
  .home-about h2 {
    max-width: none;
  }
}