:root {
  --ink: #17212b;
  --muted: #4c6070;
  --panel: #ffffff;
  --bg: #f3f5f8;
  --line: #d6dde8;
  --accent: #1d3e6f;
  --accent-2: #f1b83f;
  --good: #ecf8f2;
  --bad: #fff1ea;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--ink);
  background-color: #f7f9fc;
  background-image:
    linear-gradient(to right, rgba(42, 78, 130, 0.07) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(42, 78, 130, 0.07) 1px, transparent 1px),
    linear-gradient(180deg, #f9fbff 0%, #f3f7ff 100%);
  background-size: 28px 28px, 28px 28px, 100% 100%;
  font-family: "Zen Kaku Gothic New", sans-serif;
  line-height: 1.72;
}

.bg-shape {
  position: fixed;
  pointer-events: none;
  z-index: -1;
  filter: blur(2px);
  display: none;
}

.bg-shape-a {
  width: 280px;
  height: 280px;
  border: 2px dashed #dcae6e;
  border-radius: 50%;
  top: 55%;
  right: 6%;
  opacity: 0.3;
  animation: float-a 8s ease-in-out infinite;
}

.bg-shape-b {
  width: 210px;
  height: 210px;
  border-radius: 20px;
  background: linear-gradient(135deg, #e8f6f2, #f8dcc4);
  top: 20%;
  left: -30px;
  opacity: 0.3;
  transform: rotate(14deg);
  animation: float-b 10s ease-in-out infinite;
}

.container {
  width: calc(100% - 32px);
  max-width: none;
  margin: 0 auto;
}

.app-shell {
  display: grid;
  grid-template-columns: 380px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  margin-top: 14px;
}

.content-area {
  min-width: 0;
}

.hero {
  padding: 44px 0 30px;
  background-image:
    linear-gradient(140deg, rgba(15, 39, 70, 0.86) 0%, rgba(37, 79, 134, 0.82) 100%),
    url("./hero.png");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  color: #f5f8ff;
  border-bottom: 4px solid #f1b83f;
}

.eyebrow {
  margin: 0;
  letter-spacing: 0.14em;
  font-size: 12px;
  color: #c8daf7;
  font-weight: 700;
}

h1,
h2,
h3,
h4 {
  font-family: "M PLUS Rounded 1c", sans-serif;
  line-height: 1.3;
}

h1 {
  margin: 10px 0 10px;
  color: #ffffff;
  font-size: clamp(1.65rem, 2.4vw + 1rem, 2.6rem);
  white-space: pre-line;
}

.lead {
  margin: 0;
  color: #e8effc;
  max-width: 840px;
}

.progress {
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(50px, 1fr));
  gap: 8px;
}

.side-menu .progress {
  margin-top: 0;
  margin-bottom: 12px;
}

.progress-dot {
  height: 8px;
  border-radius: 999px;
  background: #d4dbe8;
}

.progress-dot.active {
  outline: 2px solid #c59a32;
  outline-offset: 1px;
}

.progress-dot.active:not(.done) {
  background: linear-gradient(90deg, #f5c251, #ffd982);
}

.progress-dot.done {
  background: linear-gradient(90deg, #63c48e, #86d6aa);
}

.progress-dot.active.done {
  background: linear-gradient(90deg, #63c48e, #86d6aa);
  outline: 2px solid #2c7b59;
}

.question-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 6px;
  max-height: none;
  overflow: visible;
}

.question-nav-item {
  margin: 0;
}

.question-nav-btn {
  width: 100%;
  border: 1px solid #cad5e8;
  border-radius: 12px;
  background: #f8fbff;
  padding: 8px 10px;
  text-align: left;
  cursor: pointer;
}

.question-nav-btn.active {
  border-color: #2b5a9b;
  background: #e9f0fc;
}

.qnav-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
}

.qnav-no {
  font-size: 0.73rem;
  letter-spacing: 0.06em;
  font-weight: 800;
  color: #1d4b85;
}

.qnav-title {
  margin-top: 3px;
  font-size: 0.84rem;
  line-height: 1.3;
  color: #1d2d3f;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.qnav-status {
  font-size: 0.72rem;
  padding: 2px 8px;
  border-radius: 999px;
  font-weight: 700;
}

.qnav-status.done {
  background: #d6efdf;
  color: #1f6c43;
}

.qnav-status.todo {
  background: #eeeef2;
  color: #5d6677;
}

.panel {
  background: color-mix(in srgb, var(--panel) 94%, #fefdf8 6%);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: 0 12px 30px rgba(20, 37, 44, 0.08);
  padding: 24px;
  margin-bottom: 18px;
}

.panel-intro {
}

.intro-layout {
  display: grid;
  grid-template-columns: 1fr 720px;
  gap: 18px;
}

.intro-copy {
  display: flex;
  flex-direction: column;
}

.intro-copy h2 {
  margin-top: 0;
}

.intro-copy p {
  margin: 0 0 10px;
}

.intro-action {
  margin-top: auto;
  display: flex;
  justify-content: center;
  padding-top: 8px;
}

#start-first-btn {
  min-width: 180px;
}

.intro-visual {
  border: 1px solid #cfd9ea;
  border-radius: 8px;
  background: #f8fbff;
  overflow: hidden;
}

.intro-visual img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center;
  display: block;
}

.side-menu {
  position: sticky;
  top: 14px;
  padding: 18px;
}

.side-menu h2 {
  margin: 0;
  font-size: 1.05rem;
}

.menu-summary {
  margin: 8px 0 10px;
  color: #27466f;
  font-weight: 700;
}

.problem-head {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 8px;
}

.problem-head + h2 {
  border-bottom: 1px solid rgba(31, 57, 98, 0.2);
}

.badge,
.difficulty {
  border-radius: 999px;
  padding: 4px 10px;
  font-size: 12px;
  font-weight: 700;
}

.badge {
  background: #ddece8;
  color: #205f56;
}

.difficulty {
  background: #fce9d7;
  color: #92582a;
}

.subtitle {
  margin-top: 0;
  color: var(--muted);
}

h3 {
  margin-bottom: 6px;
}

.hint {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 0.95rem;
}

.scenario {
  margin: 0;
  white-space: pre-wrap;
  background: #f9faf5;
  border: 1px solid #dde5d8;
  border-left: 5px solid var(--accent-2);
  border-radius: 12px;
  padding: 14px;
  font: inherit;
}

.exercise-block {
  margin-top: 20px;
}

.q1-block,
.q2-block,
.answer-block {
  margin-top: 28px;
  padding: 18px;
  border-radius: 14px;
  border: 1px solid #cfd9ea;
  box-shadow: 0 6px 20px rgba(26, 47, 84, 0.08);
}

.q1-block {
  background: linear-gradient(180deg, #eaf1ff 0%, #dfe9ff 100%);
}

.q2-block {
  background: linear-gradient(180deg, #fff6e4 0%, #ffefca 100%);
}

.answer-block {
  background: linear-gradient(180deg, #eef4ff 0%, #f3f8ff 100%);
}

.card-head {
  border-bottom: 1px solid rgba(31, 57, 98, 0.2);
  padding-bottom: 10px;
  margin-bottom: 12px;
}

.card-kicker {
  margin: 0;
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 800;
}

.card-head h3 {
  margin: 4px 0 0;
  font-size: 1.05rem;
  line-height: 1.35;
}

.q1-block .card-kicker {
  color: #295995;
}

.q1-block .card-head h3 {
  color: #153359;
}

.q2-block .card-kicker {
  color: #996228;
}

.q2-block .card-head h3 {
  color: #6c3f0e;
}

.answer-block .card-kicker {
  color: #2a538a;
}

.answer-block .card-head h3 {
  color: #1c3c67;
}

textarea {
  width: 100%;
  resize: vertical;
  border: 1px solid #cfd8d4;
  border-radius: 12px;
  padding: 10px 12px;
  font: inherit;
  min-height: 100px;
  background: #fff;
}

.options {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.option-item {
  border: 1px solid #d4ddd8;
  border-radius: 12px;
  padding: 10px 12px;
  background: #fefefe;
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
}

.option-item input {
  margin-top: 2px;
}

.score-text {
  margin: 10px 0 0;
  font-weight: 700;
  color: #1f5f58;
}

button {
  border: 0;
  border-radius: 12px;
  padding: 10px 16px;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition: transform 160ms ease, filter 160ms ease;
}

button:hover {
  transform: translateY(-1px);
  filter: brightness(1.03);
}

button.primary {
  background: linear-gradient(135deg, #20457a, #2a5798);
  color: #fff;
}

button.subtle {
  margin-top: 14px;
  display: block;
  margin-left: auto;
  min-width: 180px;
  padding: 10px 18px;
  background: linear-gradient(135deg, #20457a, #2a5798);
  color: #ffffff;
}

.answer-cta-wrap {
  margin-top: 22px;
  display: flex;
  justify-content: flex-end;
}

#reveal-answer {
  min-width: 180px;
}

.pager {
  display: flex;
  justify-content: space-between;
  margin: 18px 0 28px;
}

.pager button {
  background: #e7ebea;
  color: #2f4752;
}

.pager button.primary {
  background: linear-gradient(135deg, var(--accent-2), #f49f56);
  color: #fff;
}

.sample-area {
  margin-top: 14px;
}

.correct-answer-block {
  border: 1px solid #c9d7ee;
  border-radius: 12px;
  background: #f7faff;
  padding: 12px;
  margin-bottom: 12px;
}

.correct-answer-block h4 {
  margin: 0 0 8px;
  color: #1b3c68;
}

.correct-answer-label {
  margin: 8px 0 4px;
  font-weight: 700;
  color: #324b6e;
}

.correct-answer-text {
  margin: 0;
  padding: 8px 10px;
  border-radius: 8px;
  background: #ffffff;
  border: 1px solid #d4deef;
  white-space: pre-wrap;
}

.sample-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.sample-grid.single {
  grid-template-columns: 1fr;
}

.sample {
  border-radius: 12px;
  border: 1px solid #d9dfdd;
  padding: 12px;
}

.sample.bad {
  background: var(--bad);
}

.sample.good {
  background: var(--good);
}

.diagram-lines {
  border: 1px dashed #d9b7a7;
  border-radius: 10px;
  background: #fff;
  padding: 8px;
}

.diagram-good {
  border-radius: 10px;
  border: 1px dashed #98c8b8;
  background: #fff;
  padding: 8px;
}

.diagram-svg {
  width: 100%;
  height: auto;
  display: block;
}

.bad-edge {
  fill: none;
  stroke: #b26f58;
  stroke-width: 2;
  opacity: 0.85;
}

.bad-node {
  fill: #fff9f7;
  stroke: #da9d86;
  stroke-width: 1.6;
}

.bad-text {
  fill: #663225;
  font-size: 10px;
  font-weight: 700;
}

.noise-bubble {
  fill: #fde6da;
  stroke: #d79f88;
  stroke-width: 1;
}

.noise-text {
  fill: #7c5140;
  font-size: 9px;
  font-weight: 700;
}

.good-lane {
  fill: #f7fcf9;
  stroke: #b8ddd0;
  stroke-width: 1;
}

.good-lane-title {
  fill: #1f6f66;
  font-size: 12px;
  font-weight: 800;
}

.good-node {
  fill: #ffffff;
  stroke: #8dcab6;
  stroke-width: 1.4;
}

.good-edge {
  stroke: #2d7a72;
  stroke-width: 1.8;
}

.good-text {
  fill: #244f4a;
  font-size: 10px;
  font-weight: 700;
}

.checklist {
  margin: 10px 0 0;
  padding-left: 18px;
}

.coach {
  margin-top: 12px;
  border-top: 1px solid #d9dfdb;
  padding-top: 10px;
}

.ai-prompt-block {
  margin-top: 14px;
  border-top: 1px solid #d3dced;
  padding-top: 12px;
}

.ai-prompt-block h4 {
  margin: 0 0 8px;
  color: #1d3e6f;
}

.ai-prompt-text {
  width: 100%;
  border: 1px solid #c5d2e9;
  background: #f8fbff;
  border-radius: 10px;
  padding: 10px;
  font-family: "Consolas", "Menlo", monospace;
  font-size: 0.88rem;
  line-height: 1.5;
}

.ai-prompt-actions {
  margin-top: 10px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.copy-status {
  margin: 0;
  color: #36506f;
  font-size: 0.9rem;
}

.hidden {
  display: none;
}

.panel-problem {
  animation: reveal 250ms ease;
}

.panel-problem > article > section:nth-of-type(1) > h3 {
  margin-top: 3rem;
  margin-bottom: 1rem;
  padding: .75rem;
  font-size: 1.5rem;
  border-left: 4px solid rgba(31, 57, 98, 0.2);
  border-bottom: 1px solid rgba(31, 57, 98, 0.2);
}

@keyframes reveal {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes float-a {
  0%,
  100% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-8px);
  }
}

@keyframes float-b {
  0%,
  100% {
    transform: rotate(14deg) translateY(0px);
  }
  50% {
    transform: rotate(16deg) translateY(9px);
  }
}

@media (max-width: 820px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .side-menu {
    position: static;
    order: 2;
  }

  .content-area {
    order: 1;
  }

  .panel-intro {
    min-height: auto;
  }

  .intro-layout {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .intro-action {
    justify-content: flex-start;
  }

  .intro-visual img {
    min-height: 300px;
  }

  .options,
  .sample-grid {
    grid-template-columns: 1fr;
  }

  .pager {
    gap: 10px;
  }

  .pager button {
    width: 100%;
  }
}