:root {
  --bg: #f0fdf4;
  --bg-soft: #dcfce7;
  --surface: rgba(255, 255, 255, 0.82);
  --surface-strong: #f7fff9;
  --surface-tint: rgba(134, 239, 172, 0.18);
  --ink: #052e16;
  --muted: #166534;
  --line: rgba(5, 46, 22, 0.12);
  --line-strong: rgba(5, 46, 22, 0.2);
  --primary: #22c55e;
  --primary-deep: #16a34a;
  --accent: #86efac;
  --accent-strong: #bbf7d0;
  --success: #15803d;
  --danger: #b24c3d;
  --shadow: 0 24px 70px rgba(21, 128, 61, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  font-family: "Outfit", "PingFang SC", "Hiragino Sans GB", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(134, 239, 172, 0.36), transparent 26%),
    radial-gradient(circle at right 12%, rgba(34, 197, 94, 0.14), transparent 22%),
    linear-gradient(180deg, #fcfffd 0%, #f0fdf4 42%, #dcfce7 100%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(22, 163, 74, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(22, 163, 74, 0.05) 1px, transparent 1px);
  background-size: 24px 24px;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.42), transparent 86%);
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
  transition:
    transform 180ms ease,
    background 180ms ease,
    color 180ms ease,
    border-color 180ms ease,
    box-shadow 180ms ease;
}

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

h1,
h2,
h3,
.practice-quote,
.quote-line,
.mastered-text,
#flashcard-front-title,
#flashcard-front-hint,
#flashcard-back-answer {
  font-family: "Noto Serif SC", "Songti SC", serif;
}

.page-shell {
  width: min(1360px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 48px;
}

.app-frame,
.panel-card,
.quote-card,
.empty-state,
.flashcard-face {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: var(--surface);
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow);
}

.app-frame::after,
.panel-card::after,
.quote-card::after {
  content: "";
  position: absolute;
  inset: auto -8% -28% auto;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(134, 239, 172, 0.26), transparent 68%);
  pointer-events: none;
}

.app-frame {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(420px, 0.85fr);
  gap: 14px;
  margin-bottom: 16px;
}

.hero-copy,
.hero-panel {
  padding: 20px 22px;
}

.hero-head {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 18px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--primary);
  font-size: 0.82rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(1.9rem, 3.5vw, 3rem);
  line-height: 1.05;
}

h2,
h3 {
  margin: 0;
}

.hero-badge {
  margin: 4px 0 0;
  padding: 8px 12px;
  border: 1px solid rgba(34, 197, 94, 0.18);
  border-radius: 999px;
  background: rgba(240, 253, 244, 0.96);
  color: var(--primary-deep);
  white-space: nowrap;
}

.hero-text,
.workspace-copy,
.sidebar-text {
  margin: 10px 0 0;
  color: var(--muted);
  line-height: 1.55;
}

.hero-actions,
.practice-actions,
.flashcard-feedback,
.flashcard-actions-top {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-flow {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 18px;
}

.flow-pill {
  display: flex;
  gap: 12px;
  align-items: start;
  padding: 14px 16px;
  border: 1px solid rgba(5, 46, 22, 0.08);
  border-radius: 22px;
  background: rgba(247, 255, 249, 0.82);
}

.flow-pill strong,
.filter-overview-item strong {
  display: block;
}

.flow-pill p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.5;
}

.flow-step {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 34px;
  width: 34px;
  height: 34px;
  border-radius: 999px;
  background: rgba(34, 197, 94, 0.14);
  color: var(--primary-deep);
  font-weight: 700;
}

.hero-actions {
  margin-top: 14px;
}

.primary-button,
.secondary-button,
.ghost-button,
.chip-button {
  min-height: 46px;
  padding: 0 18px;
  border-radius: 999px;
  border: 1px solid transparent;
}

.primary-button {
  color: #f7fff9;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-deep) 100%);
}

.secondary-button {
  color: var(--primary-deep);
  background: rgba(240, 253, 244, 0.98);
  border-color: rgba(34, 197, 94, 0.18);
}

.ghost-button,
.chip-button {
  color: var(--muted);
  background: rgba(247, 255, 249, 0.92);
  border-color: var(--line);
}

.chip-button.is-active {
  color: #f7fff9;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-deep) 100%);
  border-color: transparent;
}

.hero-panel {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.hero-panel-header h2 {
  font-size: clamp(1.15rem, 1.8vw, 1.4rem);
}

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

.stat-card {
  padding: 12px 14px;
  border-radius: 18px;
  border: 1px solid rgba(5, 46, 22, 0.08);
  background:
    linear-gradient(180deg, rgba(247, 255, 249, 0.98), rgba(220, 252, 231, 0.96)),
    var(--surface-strong);
}

.stat-label {
  display: block;
  margin-bottom: 4px;
  color: var(--muted);
  font-size: 0.82rem;
}

.stat-card strong {
  font-size: clamp(1rem, 1.4vw, 1.2rem);
}

.stat-card-wide {
  grid-column: 1 / -1;
}

.app-layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 20px;
  align-items: start;
}

.app-sidebar {
  position: sticky;
  top: 24px;
  display: flex;
  flex-direction: column;
  gap: 24px;
  padding: 24px;
}

.sidebar-block h2 {
  font-size: 1.8rem;
}

.sidebar-note {
  padding: 16px;
  border-radius: 22px;
  background: var(--surface-tint);
}

.sidebar-note h3 {
  font-size: 1.15rem;
}

.sidebar-note .sidebar-text,
.sidebar-block .sidebar-text {
  margin-top: 10px;
}

.focus-action-button {
  width: 100%;
  margin-top: 14px;
  justify-content: center;
}

.view-nav {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.view-tab {
  display: flex;
  flex-direction: column;
  gap: 6px;
  width: 100%;
  padding: 16px 18px;
  border-radius: 22px;
  border: 1px solid var(--line);
  background: rgba(255, 252, 247, 0.78);
  text-align: left;
}

.view-tab.is-active {
  border-color: rgba(34, 197, 94, 0.28);
  background:
    linear-gradient(135deg, rgba(240, 253, 244, 0.98), rgba(187, 247, 208, 0.88)),
    var(--surface-strong);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.55);
}

.view-tab-label {
  color: var(--ink);
  font-weight: 600;
}

.view-tab-meta {
  color: var(--muted);
  font-size: 0.92rem;
}

.workspace {
  min-width: 0;
}

.workspace-view {
  display: none;
  flex-direction: column;
  gap: 18px;
}

.workspace-view.is-active {
  display: flex;
}

.workspace-header,
.panel-card {
  padding: 24px;
}

.workspace-header {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 22px;
}

.workspace-header h2 {
  font-size: clamp(1.4rem, 2.2vw, 1.9rem);
}

.workspace-copy {
  max-width: 24rem;
  margin: 0;
}

.explore-layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.panel-span-2 {
  grid-column: 1 / -1;
}

.spotlight-card {
  background:
    linear-gradient(135deg, rgba(247, 255, 249, 0.96), rgba(187, 247, 208, 0.42)),
    var(--surface);
}

.filter-overview-card {
  background:
    linear-gradient(135deg, rgba(247, 255, 249, 0.96), rgba(134, 239, 172, 0.24)),
    var(--surface);
}

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

.filter-overview-item {
  padding: 16px 18px;
  border-radius: 22px;
  border: 1px solid rgba(5, 46, 22, 0.08);
  background: rgba(247, 255, 249, 0.82);
}

.filter-overview-item strong {
  margin-top: 4px;
  font-size: 1.05rem;
  line-height: 1.6;
}

.filter-overview-item-wide {
  grid-column: 1 / -1;
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 14px;
}

.compact-heading h2 {
  font-size: clamp(1.4rem, 2vw, 1.85rem);
}

.input-label,
.result-count,
.practice-meta,
.quote-category,
.quote-author,
.mastered-meta,
.quiz-feedback,
.flashcard-meta p {
  margin: 0;
  color: var(--muted);
}

.input-label {
  margin-bottom: 12px;
  font-size: 0.95rem;
}

.text-input {
  width: 100%;
  min-height: 52px;
  padding: 0 16px;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(255, 254, 251, 0.98);
  outline: none;
}

.text-input:focus {
  border-color: rgba(34, 197, 94, 0.42);
  box-shadow: 0 0 0 4px rgba(34, 197, 94, 0.12);
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.practice-card {
  padding-top: 2px;
}

.practice-quote {
  margin: 16px 0 0;
  font-size: clamp(1.28rem, 2vw, 1.56rem);
  line-height: 1.9;
}

.practice-actions {
  margin-top: 22px;
}

.quote-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.quote-card,
.empty-state {
  padding: 22px;
}

.quote-card {
  cursor: pointer;
  background:
    linear-gradient(180deg, rgba(247, 255, 249, 0.96), rgba(220, 252, 231, 0.82)),
    var(--surface);
}

.quote-card:hover,
.quiz-option:hover,
.view-tab:hover {
  box-shadow: 0 18px 42px rgba(71, 43, 24, 0.1);
}

.quote-card-header {
  display: flex;
  gap: 12px;
  align-items: start;
  justify-content: space-between;
}

.quote-category {
  margin-bottom: 6px;
  font-size: 0.88rem;
}

.quote-title {
  font-size: 1.3rem;
}

.quote-author {
  margin-top: 14px;
}

.quote-lines {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.quote-line {
  position: relative;
  margin: 0;
  padding-left: 18px;
  line-height: 1.9;
}

.quote-line::before {
  content: "◦";
  position: absolute;
  left: 0;
  color: var(--primary);
}

.flashcard-panel,
.quiz-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.flashcard-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.flashcard {
  position: relative;
  width: 100%;
  min-height: 320px;
  padding: 0;
  border: none;
  background: transparent;
  perspective: 1200px;
}

.flashcard-face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 18px;
  padding: 24px;
  backface-visibility: hidden;
  transition: transform 420ms ease, box-shadow 200ms ease;
  text-align: left;
  background:
    linear-gradient(180deg, rgba(247, 255, 249, 0.98), rgba(220, 252, 231, 0.96)),
    var(--surface-strong);
}

.flashcard:hover .flashcard-face {
  box-shadow: 0 24px 65px rgba(21, 128, 61, 0.16);
}

.flashcard-front {
  transform: rotateY(0deg);
}

.flashcard-back {
  transform: rotateY(180deg);
  justify-content: center;
  align-items: center;
  background:
    linear-gradient(180deg, rgba(34, 197, 94, 0.96), rgba(22, 163, 74, 0.98)),
    var(--primary-deep);
  color: #f7fff9;
  text-align: center;
}

.flashcard.is-flipped .flashcard-front {
  transform: rotateY(-180deg);
}

.flashcard.is-flipped .flashcard-back {
  transform: rotateY(0deg);
}

.flashcard-tag {
  display: inline-flex;
  width: fit-content;
  align-items: center;
  min-height: 34px;
  padding: 0 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.72);
  color: var(--primary-deep);
  font-size: 0.85rem;
  letter-spacing: 0.04em;
}

.flashcard-back .flashcard-tag {
  position: absolute;
  top: 24px;
  left: 24px;
  background: rgba(240, 253, 244, 0.16);
  color: #dcfce7;
}

#flashcard-front-title {
  font-size: 1.7rem;
  line-height: 1.45;
}

#flashcard-front-hint,
#flashcard-back-answer {
  font-size: 1.02rem;
  line-height: 2;
}

#flashcard-back-answer {
  max-width: 100%;
  font-size: clamp(1.35rem, 2.4vw, 1.85rem);
  line-height: 1.85;
}

.quiz-stem {
  margin: 0;
  font-size: 1.18rem;
  line-height: 1.8;
}

.quiz-options {
  display: grid;
  gap: 12px;
}

.quiz-option {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  width: 100%;
  padding: 16px 18px;
  border-radius: 20px;
  border: 1px solid var(--line);
  background: rgba(247, 255, 249, 0.92);
  color: var(--ink);
  text-align: left;
}

.quiz-option.is-correct {
  border-color: rgba(21, 128, 61, 0.35);
  background: rgba(236, 253, 245, 0.96);
}

.quiz-option.is-wrong {
  border-color: rgba(178, 76, 61, 0.3);
  background: rgba(253, 242, 240, 0.96);
}

.quiz-option-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 999px;
  background: rgba(134, 239, 172, 0.55);
  color: var(--primary-deep);
  font-weight: 700;
}

.empty-state {
  grid-column: 1 / -1;
  text-align: center;
}

.empty-state h3 {
  font-size: 1.35rem;
}

.empty-state p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.8;
}

@media (max-width: 1120px) {
  .app-frame,
  .app-layout,
  .explore-layout {
    grid-template-columns: 1fr;
  }

  .app-sidebar {
    position: static;
  }

  .hero-flow,
  .stats-grid,
  .filter-overview-grid {
    grid-template-columns: 1fr;
  }

  .view-nav {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 840px) {
  body::before {
    background-size: 32px 32px;
  }

  .hero-head,
  .workspace-header,
  .flashcard-meta {
    flex-direction: column;
    align-items: start;
  }

  .quote-grid {
    grid-template-columns: 1fr;
  }

  .workspace-copy {
    max-width: none;
  }

  .app-layout {
    gap: 14px;
  }

  .app-sidebar {
    top: 12px;
    z-index: 10;
    gap: 12px;
    padding: 14px;
    border-radius: 22px;
    background: rgba(247, 255, 249, 0.92);
    backdrop-filter: blur(24px);
  }

  .app-sidebar .sidebar-block,
  .app-sidebar .sidebar-note {
    display: none;
  }

  .view-nav {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 8px;
  }

  .view-tab {
    align-items: center;
    justify-content: center;
    min-height: 58px;
    padding: 12px 10px;
    border-radius: 18px;
    text-align: center;
  }

  .view-tab-label {
    font-size: 0.96rem;
  }

  .view-tab-meta {
    display: none;
  }

  .workspace-view {
    gap: 14px;
  }

  .hero-copy,
  .hero-panel,
  .workspace-header,
  .panel-card {
    padding-top: 18px;
    padding-bottom: 18px;
  }

  .workspace-header {
    gap: 10px;
    align-items: start;
  }

  .section-heading {
    flex-direction: column;
    align-items: start;
    gap: 8px;
  }

  .hero-actions,
  .flashcard-feedback,
  .flashcard-actions-top {
    width: 100%;
  }

  .hero-actions > button,
  .flashcard-feedback > button,
  .flashcard-actions-top > button {
    flex: 1 1 calc(50% - 6px);
    min-width: 0;
  }

  .chip-row {
    gap: 8px;
    overflow-x: auto;
    flex-wrap: nowrap;
    padding-bottom: 4px;
    scrollbar-width: none;
  }

  .chip-row::-webkit-scrollbar {
    display: none;
  }

  .chip-button {
    flex: 0 0 auto;
  }

  .flow-pill,
  .filter-overview-item {
    padding: 14px;
  }

  .quote-card-header {
    flex-direction: column;
    align-items: start;
  }

  .quote-mastered-button {
    width: 100%;
   }

  .result-count {
    font-size: 0.95rem;
  }
}

@media (max-width: 640px) {
  .page-shell {
    width: min(100% - 20px, 1360px);
    padding-top: 20px;
  }

  .app-frame,
  .panel-card,
  .quote-card,
  .empty-state,
  .flashcard-face {
    border-radius: 24px;
  }

  .hero-copy,
  .hero-panel,
  .workspace-header,
  .panel-card,
  .quote-card,
  .empty-state {
    padding-left: 18px;
    padding-right: 18px;
  }

  h1 {
    font-size: 2.2rem;
  }

  .hero-badge {
    white-space: normal;
  }

  .hero-text {
    font-size: 0.98rem;
  }

  .stats-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .hero-flow,
  .filter-overview-grid {
    grid-template-columns: 1fr;
  }

  .stat-card {
    padding: 16px;
  }

  .flashcard {
    min-height: 340px;
  }

  .flashcard-face {
    padding: 18px;
  }

  #flashcard-front-title {
    font-size: 1.4rem;
  }

  #flashcard-front-hint,
  #flashcard-back-answer {
    line-height: 1.8;
  }

  .quiz-option {
    grid-template-columns: 30px minmax(0, 1fr);
    padding: 14px;
  }

  .view-nav {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .view-tab {
    min-height: 54px;
    padding: 10px 8px;
  }

  .view-tab-label {
    font-size: 0.9rem;
  }
}

@media (max-width: 420px) {
  .page-shell {
    width: min(100% - 16px, 1360px);
  }

  .hero-actions > button,
  .practice-actions > button,
  .flashcard-feedback > button,
  .flashcard-actions-top > button {
    flex-basis: 100%;
  }

  .view-tab-label {
    font-size: 0.84rem;
  }
}