:root {
  color-scheme: light;
  --bg: #f5f7f4;
  --bg-strong: #eef2ec;
  --surface: rgba(255, 255, 255, 0.88);
  --surface-solid: #ffffff;
  --surface-soft: #f4f7f3;
  --ink: #17251d;
  --muted: #66736a;
  --line: #dce4dc;
  --line-strong: #c8d3c9;
  --green: #1f8a56;
  --green-dark: #12633d;
  --green-soft: #def3e5;
  --lime: #c9f36a;
  --amber: #e49b2f;
  --amber-soft: #fff1d8;
  --red: #cf4b4b;
  --red-soft: #fde7e5;
  --blue: #3e70be;
  --blue-soft: #e7efff;
  --shadow: 0 18px 50px rgba(32, 54, 40, 0.08);
  --shadow-small: 0 8px 24px rgba(32, 54, 40, 0.07);
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 10px;
  --mono: "Cascadia Code", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --sans: "Segoe UI", "Microsoft YaHei UI", "PingFang SC", "Noto Sans CJK SC", sans-serif;
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0e1712;
  --bg-strong: #111c16;
  --surface: rgba(20, 33, 26, 0.9);
  --surface-solid: #15231b;
  --surface-soft: #1a2a21;
  --ink: #edf6ef;
  --muted: #9caf9f;
  --line: #2a3c30;
  --line-strong: #385143;
  --green: #59c986;
  --green-dark: #87e5aa;
  --green-soft: #173d28;
  --lime: #b9ea61;
  --amber: #f0b75b;
  --amber-soft: #44331a;
  --red: #ff7772;
  --red-soft: #442321;
  --blue: #82aaf0;
  --blue-soft: #202f4d;
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.24);
  --shadow-small: 0 8px 24px rgba(0, 0, 0, 0.2);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
  background:
    radial-gradient(circle at 12% 6%, rgba(201, 243, 106, 0.2), transparent 26rem),
    linear-gradient(140deg, var(--bg), var(--bg-strong));
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.6;
}

button, input, textarea { font: inherit; }

button { color: inherit; }

button:focus-visible,
input:focus-visible,
textarea:focus-visible,
a:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--green) 38%, transparent);
  outline-offset: 2px;
}

.hidden { display: none !important; }

.ambient {
  position: fixed;
  z-index: -1;
  border-radius: 999px;
  filter: blur(10px);
  pointer-events: none;
}

.ambient-one {
  top: 38%;
  right: -12rem;
  width: 30rem;
  height: 30rem;
  background: rgba(62, 112, 190, 0.08);
}

.ambient-two {
  bottom: -14rem;
  left: 18%;
  width: 34rem;
  height: 34rem;
  background: rgba(31, 138, 86, 0.07);
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  display: grid;
  grid-template-columns: minmax(230px, 1fr) auto minmax(230px, 1fr);
  align-items: center;
  gap: 24px;
  min-height: 76px;
  padding: 12px clamp(18px, 3vw, 44px);
  border-bottom: 1px solid color-mix(in srgb, var(--line) 75%, transparent);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  width: fit-content;
  color: inherit;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 14px 8px 14px 8px;
  background: var(--ink);
  color: var(--lime);
  font-family: var(--mono);
  font-size: 24px;
  font-weight: 800;
  box-shadow: var(--shadow-small);
}

.brand strong,
.brand small { display: block; }

.brand strong { font-size: 15px; letter-spacing: 0.01em; }
.brand small { margin-top: -2px; color: var(--muted); font-size: 11px; }

.topnav {
  display: flex;
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  box-shadow: var(--shadow-small);
}

.nav-btn {
  border: 0;
  border-radius: 999px;
  padding: 9px 16px;
  background: transparent;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: 160ms ease;
}

.nav-btn:hover { color: var(--ink); background: var(--surface-soft); }
.nav-btn.active { color: #fff; background: var(--green); }
[data-theme="dark"] .nav-btn.active { color: #0d1a12; }

.nav-count {
  display: inline-grid;
  place-items: center;
  min-width: 20px;
  height: 20px;
  margin-left: 3px;
  padding: 0 5px;
  border-radius: 999px;
  background: var(--red-soft);
  color: var(--red);
  font-size: 11px;
}

.nav-btn.active .nav-count { background: rgba(255, 255, 255, 0.22); color: #fff; }

.top-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
}

.icon-btn,
.primary-btn,
.secondary-btn,
.ghost-btn,
.text-btn,
.back-btn,
.filter-pill,
.topic-btn,
.answer-option {
  border: 0;
  cursor: pointer;
  transition: transform 150ms ease, background 150ms ease, border-color 150ms ease, color 150ms ease, box-shadow 150ms ease;
}

.icon-btn {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--surface);
  font-size: 18px;
}

.icon-btn:hover { transform: rotate(15deg); border-color: var(--green); }

.primary-btn,
.secondary-btn,
.ghost-btn {
  border-radius: 12px;
  padding: 12px 18px;
  font-weight: 800;
}

.primary-btn {
  background: var(--green);
  color: #fff;
  box-shadow: 0 8px 20px color-mix(in srgb, var(--green) 24%, transparent);
}

[data-theme="dark"] .primary-btn { color: #0b1810; }
.primary-btn:hover { transform: translateY(-2px); background: var(--green-dark); }
.primary-btn:active, .secondary-btn:active, .ghost-btn:active { transform: translateY(0) scale(0.98); }
.primary-btn.compact { padding: 10px 15px; font-size: 12px; }

.secondary-btn {
  border: 1px solid var(--line-strong);
  background: var(--surface-solid);
  color: var(--ink);
}

.secondary-btn:hover { border-color: var(--green); color: var(--green); }

.ghost-btn {
  background: transparent;
  color: var(--green);
}

.ghost-btn:hover { background: var(--green-soft); }

.app-shell {
  display: grid;
  grid-template-columns: 282px minmax(0, 1fr);
  gap: 0;
  max-width: 1600px;
  min-height: calc(100vh - 76px);
  margin: 0 auto;
}

.sidebar {
  position: sticky;
  top: 76px;
  align-self: start;
  height: calc(100vh - 76px);
  overflow-y: auto;
  padding: 24px 18px 28px 28px;
  border-right: 1px solid var(--line);
  scrollbar-width: thin;
}

.progress-card {
  display: grid;
  grid-template-columns: 88px 1fr;
  align-items: center;
  gap: 14px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--surface);
  box-shadow: var(--shadow-small);
}

.progress-ring {
  --size: 84px;
  display: grid;
  place-items: center;
  width: var(--size);
  height: var(--size);
  border-radius: 50%;
  background: conic-gradient(var(--green) calc(var(--progress) * 1%), var(--line) 0);
  position: relative;
}

.progress-ring::after {
  content: "";
  position: absolute;
  inset: 7px;
  border-radius: inherit;
  background: var(--surface-solid);
}

.progress-ring > div { position: relative; z-index: 1; text-align: center; }
.progress-ring strong { display: block; font-family: var(--mono); font-size: 20px; line-height: 1.1; }
.progress-ring small { color: var(--muted); font-size: 10px; }
.progress-copy strong { display: block; font-size: 14px; }
.progress-copy p { margin: 3px 0 7px; color: var(--muted); font-size: 11px; }
.mini-stats { display: flex; flex-wrap: wrap; gap: 4px 10px; color: var(--muted); font-size: 10px; }
.mini-stats b { color: var(--ink); }

.search-box {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 18px 0 12px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
}

.search-box span { color: var(--muted); font-size: 18px; }
.search-box input { width: 100%; border: 0; outline: 0; background: transparent; color: var(--ink); font-size: 12px; }
.search-box input::placeholder { color: color-mix(in srgb, var(--muted) 75%, transparent); }

.module-nav { display: grid; gap: 4px; }

.module-nav-item {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr) auto;
  align-items: center;
  gap: 9px;
  width: 100%;
  padding: 9px 8px;
  border: 0;
  border-radius: 11px;
  background: transparent;
  text-align: left;
  cursor: pointer;
}

.module-nav-item:hover { background: var(--surface-soft); }
.module-nav-item.active { background: var(--green-soft); color: var(--green-dark); }
.module-nav-index {
  display: grid;
  place-items: center;
  width: 27px;
  height: 27px;
  border-radius: 9px;
  background: var(--surface-soft);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 800;
}
.module-nav-item.active .module-nav-index { background: var(--green); color: #fff; }
.module-nav-title { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 11px; font-weight: 700; }
.module-nav-count { color: var(--muted); font-family: var(--mono); font-size: 10px; }
.sidebar-footer { margin-top: 22px; padding-top: 14px; border-top: 1px solid var(--line); text-align: center; }
.text-btn { padding: 4px; background: transparent; font-size: 11px; text-decoration: underline; text-underline-offset: 3px; }
.text-btn.danger { color: var(--red); }
.sidebar-footer p { margin: 7px 0 0; color: var(--muted); font-size: 10px; }

.main-content { min-width: 0; padding: clamp(24px, 4vw, 52px); }
.view { display: none; animation: fadeUp 260ms ease; }
.view.active { display: block; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.hero-card {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(310px, 0.85fr);
  gap: 38px;
  overflow: hidden;
  padding: clamp(28px, 5vw, 58px);
  border: 1px solid color-mix(in srgb, var(--green) 18%, var(--line));
  border-radius: var(--radius-xl);
  background:
    linear-gradient(135deg, color-mix(in srgb, var(--green-soft) 68%, var(--surface-solid)), var(--surface-solid)),
    var(--surface-solid);
  box-shadow: var(--shadow);
}

.hero-card::after {
  content: "";
  position: absolute;
  right: -6rem;
  bottom: -9rem;
  width: 24rem;
  height: 24rem;
  border: 1px solid color-mix(in srgb, var(--green) 18%, transparent);
  border-radius: 50%;
  box-shadow: 0 0 0 3rem color-mix(in srgb, var(--green) 4%, transparent), 0 0 0 7rem color-mix(in srgb, var(--green) 3%, transparent);
  pointer-events: none;
}

.eyebrow {
  display: inline-block;
  color: var(--green);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero-copy { position: relative; z-index: 1; }
.hero-copy h1 { margin: 12px 0 14px; max-width: 680px; font-size: clamp(34px, 4.5vw, 62px); line-height: 1.07; letter-spacing: -0.05em; }
.hero-copy h1 em { color: var(--green); font-style: normal; }
.hero-copy > p { max-width: 620px; margin: 0; color: var(--muted); font-size: 15px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }

.hero-terminal {
  position: relative;
  z-index: 1;
  align-self: center;
  overflow: hidden;
  border: 1px solid #2e4437;
  border-radius: 18px;
  background: #101b15;
  color: #eef9f0;
  box-shadow: 0 24px 55px rgba(16, 27, 21, 0.25);
  transform: rotate(1.5deg);
}

.terminal-bar { display: flex; align-items: center; gap: 6px; padding: 11px 14px; border-bottom: 1px solid #2c3e34; background: #16241c; }
.terminal-bar i { width: 8px; height: 8px; border-radius: 50%; background: #ff6b64; }
.terminal-bar i:nth-child(2) { background: #f5c451; }
.terminal-bar i:nth-child(3) { background: #62cf7a; }
.terminal-bar span { margin-left: 5px; color: #91a798; font-family: var(--mono); font-size: 10px; }
.hero-terminal pre { margin: 0; padding: 22px; overflow-x: auto; font-family: var(--mono); font-size: 12px; line-height: 1.9; }
.code-muted { color: #7f9587; }
.code-key { color: #c9f36a; }
.code-fn { color: #83b7ff; }
.code-string { color: #ffd27d; }
.terminal-result { padding: 12px 22px 16px; border-top: 1px dashed #2c3e34; color: #a8caae; font-family: var(--mono); font-size: 11px; }
.terminal-result span { color: #c9f36a; }

.dashboard-heading { display: flex; align-items: end; justify-content: space-between; gap: 18px; margin: 38px 0 18px; }
.dashboard-heading h2 { margin: 4px 0 0; font-size: 25px; letter-spacing: -0.03em; }
.filter-pills { display: flex; gap: 5px; padding: 4px; border: 1px solid var(--line); border-radius: 999px; background: var(--surface); }
.filter-pill { border-radius: 999px; padding: 7px 12px; background: transparent; color: var(--muted); font-size: 11px; font-weight: 800; }
.filter-pill.active { background: var(--ink); color: var(--bg); }
.search-summary { margin-bottom: 18px; padding: 12px 15px; border-radius: 12px; background: var(--blue-soft); color: var(--blue); font-size: 12px; }

.module-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.module-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--surface);
  box-shadow: var(--shadow-small);
  transition: transform 180ms ease, border-color 180ms ease;
}
.module-card:hover { transform: translateY(-3px); border-color: color-mix(in srgb, var(--green) 42%, var(--line)); }
.module-card-head { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; align-items: center; gap: 13px; padding: 19px 19px 15px; }
.module-number { display: grid; place-items: center; width: 41px; height: 41px; border-radius: 13px; background: var(--module-soft, var(--green-soft)); color: var(--module-color, var(--green-dark)); font-family: var(--mono); font-weight: 900; }
.module-card h3 { margin: 0; font-size: 15px; letter-spacing: -0.02em; }
.module-card p { margin: 2px 0 0; color: var(--muted); font-size: 11px; }
.module-progress { min-width: 55px; text-align: right; }
.module-progress strong { display: block; color: var(--module-color, var(--green)); font-family: var(--mono); font-size: 14px; }
.module-progress span { color: var(--muted); font-size: 9px; }
.module-bar { height: 4px; margin: 0 19px 12px; overflow: hidden; border-radius: 999px; background: var(--line); }
.module-bar i { display: block; height: 100%; border-radius: inherit; background: var(--module-color, var(--green)); transition: width 300ms ease; }
.topic-list { display: grid; gap: 1px; padding: 0 10px 12px; }
.topic-btn { display: grid; grid-template-columns: 22px minmax(0, 1fr) auto; align-items: center; gap: 8px; width: 100%; padding: 9px 10px; border-radius: 10px; background: transparent; text-align: left; }
.topic-btn:hover { background: var(--surface-soft); }
.topic-status { display: grid; place-items: center; width: 20px; height: 20px; border: 1px solid var(--line-strong); border-radius: 7px; color: transparent; font-size: 11px; font-weight: 900; }
.topic-btn.done .topic-status { border-color: var(--green); background: var(--green); color: #fff; }
.topic-title { overflow: hidden; color: var(--ink); font-size: 11px; font-weight: 700; text-overflow: ellipsis; white-space: nowrap; }
.topic-source { color: var(--muted); font-family: var(--mono); font-size: 9px; }

.practice-topline { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 20px; }
.back-btn { padding: 7px 0; background: transparent; color: var(--muted); font-size: 12px; font-weight: 800; }
.back-btn:hover { color: var(--green); }
.session-label { padding: 7px 11px; border-radius: 999px; background: var(--amber-soft); color: var(--amber); font-size: 11px; font-weight: 800; }
.practice-layout { display: grid; grid-template-columns: minmax(280px, 0.82fr) minmax(0, 1.18fr); align-items: start; gap: 22px; }
.lesson-panel,
.exercise-panel { border: 1px solid var(--line); border-radius: var(--radius-xl); background: var(--surface); box-shadow: var(--shadow-small); }
.lesson-panel { position: sticky; top: 100px; padding: clamp(22px, 3vw, 34px); }
.lesson-meta { display: flex; flex-wrap: wrap; gap: 8px; }
.module-tag, .source-tag, .difficulty-badge { padding: 6px 9px; border-radius: 999px; font-size: 10px; font-weight: 800; }
.module-tag { background: var(--green-soft); color: var(--green-dark); }
.source-tag { background: var(--surface-soft); color: var(--muted); font-family: var(--mono); }
.lesson-panel h1 { margin: 15px 0 22px; font-size: clamp(26px, 3vw, 38px); line-height: 1.15; letter-spacing: -0.04em; }
.knowledge-card { padding: 18px; border: 1px solid var(--line); border-radius: var(--radius-lg); background: var(--surface-solid); }
.section-title { display: flex; align-items: center; gap: 10px; }
.section-title span { display: grid; place-items: center; width: 27px; height: 27px; border-radius: 8px; background: var(--ink); color: var(--lime); font-family: var(--mono); font-size: 9px; font-weight: 900; }
.section-title h2 { margin: 0; font-size: 13px; }
.knowledge-list { display: grid; gap: 10px; margin: 17px 0 0; padding: 0; list-style: none; }
.knowledge-list li { position: relative; padding-left: 19px; color: var(--muted); font-size: 12px; }
.knowledge-list li::before { content: ""; position: absolute; top: 0.68em; left: 1px; width: 7px; height: 7px; border-radius: 2px; background: var(--green); transform: rotate(45deg); }
.note-tip { margin-top: 16px; padding: 14px 15px; border-left: 3px solid var(--amber); border-radius: 0 12px 12px 0; background: var(--amber-soft); color: color-mix(in srgb, var(--ink) 82%, var(--amber)); font-size: 11px; }

.exercise-panel { min-height: 580px; padding: clamp(22px, 3vw, 34px); }
.exercise-header { display: flex; align-items: start; justify-content: space-between; gap: 20px; padding-bottom: 18px; border-bottom: 1px solid var(--line); }
.exercise-header h2 { margin: 4px 0 0; font-size: 20px; letter-spacing: -0.025em; }
.difficulty-badge { flex: 0 0 auto; background: var(--blue-soft); color: var(--blue); }
.question-content { padding: 22px 0 8px; }
.question-content p { margin: 0 0 12px; white-space: pre-line; font-size: 14px; }
.question-code { margin: 12px 0 0; padding: 17px; overflow-x: auto; border: 1px solid #2e4437; border-radius: 14px; background: #101b15; color: #eef9f0; font-family: var(--mono); font-size: 12px; line-height: 1.7; }
.question-code code { font-family: inherit; }
.answer-area { display: grid; gap: 9px; margin: 12px 0 16px; }
.answer-option { display: grid; grid-template-columns: 30px minmax(0, 1fr); align-items: center; gap: 10px; width: 100%; padding: 11px 13px; border: 1px solid var(--line); border-radius: 13px; background: var(--surface-solid); text-align: left; font-size: 12px; }
.answer-option:hover { border-color: var(--green); transform: translateX(2px); }
.answer-option.selected { border-color: var(--green); background: var(--green-soft); }
.answer-key { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 9px; background: var(--surface-soft); color: var(--muted); font-family: var(--mono); font-size: 11px; font-weight: 900; }
.answer-option.selected .answer-key { background: var(--green); color: #fff; }
.answer-option.correct { border-color: var(--green); background: var(--green-soft); }
.answer-option.wrong { border-color: var(--red); background: var(--red-soft); }
.answer-option:disabled { cursor: default; transform: none; }

.answer-textarea,
.code-textarea {
  width: 100%;
  min-height: 128px;
  resize: vertical;
  border: 1px solid var(--line-strong);
  border-radius: 14px;
  padding: 14px 15px;
  outline: 0;
  background: var(--surface-solid);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 12px;
  line-height: 1.65;
  tab-size: 2;
}
.answer-textarea:focus,
.code-textarea:focus { border-color: var(--green); box-shadow: 0 0 0 4px color-mix(in srgb, var(--green) 12%, transparent); }
.code-textarea { min-height: 260px; background: #101b15; color: #edf6ef; border-color: #2e4437; }
.input-help { margin: -4px 0 0; color: var(--muted); font-size: 10px; }
.feedback { margin: 4px 0 18px; padding: 14px 16px; border-radius: 13px; font-size: 12px; white-space: pre-line; }
.feedback.success { background: var(--green-soft); color: var(--green-dark); }
.feedback.error { background: var(--red-soft); color: var(--red); }
.feedback.info { background: var(--blue-soft); color: var(--blue); }
.feedback strong { display: block; margin-bottom: 3px; }
.exercise-actions { display: flex; flex-wrap: wrap; gap: 9px; margin-top: 8px; }
.solution-box { margin-top: 24px; padding-top: 22px; border-top: 1px solid var(--line); }
.solution-box pre { margin: 17px 0 0; padding: 18px; overflow-x: auto; border: 1px solid #2e4437; border-radius: 14px; background: #101b15; color: #eef9f0; font-family: var(--mono); font-size: 12px; line-height: 1.7; }
.solution-box code { font-family: inherit; }
.test-cases { display: grid; gap: 7px; margin-top: 12px; }
.test-case { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface-soft); font-family: var(--mono); font-size: 10px; }
.test-case span { color: var(--muted); }
.test-case b { color: var(--ink); }

.review-hero { padding: clamp(28px, 5vw, 52px); border-radius: var(--radius-xl); background: linear-gradient(135deg, var(--amber-soft), var(--surface-solid)); border: 1px solid color-mix(in srgb, var(--amber) 28%, var(--line)); box-shadow: var(--shadow); }
.review-hero h1 { margin: 9px 0 12px; font-size: clamp(30px, 4vw, 50px); line-height: 1.1; letter-spacing: -0.045em; }
.review-hero p { max-width: 690px; margin: 0; color: var(--muted); font-size: 13px; }
.review-stats { display: flex; flex-wrap: wrap; gap: 30px; margin-top: 28px; }
.review-stats div { min-width: 120px; }
.review-stats strong { display: block; font-family: var(--mono); font-size: 26px; }
.review-stats span { color: var(--muted); font-size: 10px; }
.review-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; margin-top: 20px; }
.review-item { display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: center; gap: 15px; padding: 18px; border: 1px solid var(--line); border-radius: var(--radius-lg); background: var(--surface); box-shadow: var(--shadow-small); }
.review-item h3 { margin: 4px 0; font-size: 14px; }
.review-item p { margin: 0; color: var(--muted); font-size: 10px; }
.review-item .secondary-btn { padding: 9px 12px; font-size: 11px; }
.empty-state { grid-column: 1 / -1; padding: 58px 22px; border: 1px dashed var(--line-strong); border-radius: var(--radius-lg); color: var(--muted); text-align: center; }
.empty-state strong { display: block; margin-bottom: 5px; color: var(--ink); font-size: 18px; }
.empty-state p { margin: 0; font-size: 12px; }

.toast { position: fixed; z-index: 100; right: 22px; bottom: 22px; max-width: 340px; padding: 12px 16px; border-radius: 12px; background: var(--ink); color: var(--bg); box-shadow: var(--shadow); font-size: 12px; font-weight: 700; opacity: 0; transform: translateY(12px); pointer-events: none; transition: 200ms ease; }
.toast.show { opacity: 1; transform: translateY(0); }

@media (max-width: 1180px) {
  .topbar { grid-template-columns: 1fr auto; }
  .topnav { order: 3; grid-column: 1 / -1; justify-self: center; margin-bottom: -4px; }
  .app-shell { grid-template-columns: 240px minmax(0, 1fr); }
  .sidebar { padding-left: 18px; }
  .hero-card { grid-template-columns: 1fr; }
  .hero-terminal { max-width: 560px; }
  .module-grid, .review-list { grid-template-columns: 1fr; }
}

@media (max-width: 860px) {
  .topbar { position: relative; grid-template-columns: 1fr auto; padding: 12px 16px 14px; }
  .top-actions .compact { display: none; }
  .app-shell { display: block; min-height: 0; }
  .sidebar { position: relative; top: 0; height: auto; padding: 16px; border-right: 0; border-bottom: 1px solid var(--line); }
  .progress-card { grid-template-columns: 74px 1fr; }
  .progress-ring { --size: 72px; }
  .module-nav { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .sidebar-footer { display: none; }
  .main-content { padding: 22px 16px 40px; }
  .practice-layout { grid-template-columns: 1fr; }
  .lesson-panel { position: static; }
}

@media (max-width: 560px) {
  .brand small { display: none; }
  .top-actions { gap: 4px; }
  .icon-btn { width: 38px; height: 38px; }
  .topnav { width: 100%; overflow-x: auto; border-radius: 14px; }
  .nav-btn { flex: 1; padding-inline: 8px; white-space: nowrap; }
  .module-nav { grid-template-columns: 1fr; }
  .hero-card { padding: 24px 19px; border-radius: 22px; }
  .hero-copy h1 { font-size: 36px; }
  .hero-actions { flex-direction: column; }
  .hero-actions button { width: 100%; }
  .dashboard-heading { align-items: start; flex-direction: column; }
  .module-card-head { grid-template-columns: auto minmax(0, 1fr); }
  .module-progress { grid-column: 1 / -1; display: flex; align-items: center; gap: 8px; text-align: left; }
  .test-case { grid-template-columns: 1fr; }
  .review-item { grid-template-columns: 1fr; }
  .review-item button { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}