:root{--bg-start: #ffffff;--bg-end: #ffffff;--panel: #ffffff;--card-front: #ffffff;--card-back: #ffffff;--text-main: #243121;--text-body: rgba(36, 49, 33, .9);--text-muted: #61705b;--text-secondary: rgba(36, 49, 33, .68);--text-tertiary: rgba(36, 49, 33, .5);--accent: #567a47;--accent-strong: #38572d;--accent-deep: #2d4a23;--accent-border: rgba(56, 87, 45, .22);--accent-soft: rgba(56, 87, 45, .18);--border: rgba(36, 49, 33, .08);--shadow: 0 2px 10px rgba(54, 73, 46, .03);--soft-bg: transparent}*{box-sizing:border-box}html,body,#app{min-height:100%}body{margin:0;font-family:Inter,PingFang SC,Microsoft YaHei,sans-serif;color:var(--text-main);background:#fff}a{color:inherit}button{font:inherit}.page-shell{width:min(100%,1080px);margin:0 auto;padding:24px 14px 40px}.home-page-shell{padding-top:28px}.hero{text-align:center;margin-bottom:14px}.hero h1{margin:0;font-size:clamp(1.8rem,5.4vw,2.4rem);font-weight:700}.hero-stats{margin-top:14px;display:inline-flex;flex-wrap:wrap;justify-content:center;gap:8px}.hero-stats span{padding:6px 10px;border-radius:999px;background:#567a471a;color:var(--accent-strong);font-size:.88rem;font-weight:700}.progress-text{padding:0;margin:0;background:transparent;color:#2431219e;font-size:.84rem;font-weight:600}.app-panel,.topic-category-card,.card-surface{background:var(--panel);border:1px solid var(--border);box-shadow:var(--shadow)}.app-panel{border-radius:18px;padding:12px}.level-panel,.coming-soon-panel{margin-bottom:14px}.level-grid{display:grid;grid-template-columns:repeat(1,minmax(0,1fr));gap:10px}.level-card{position:relative;border:1px solid var(--border);border-radius:14px;padding:14px;background:#fff;text-align:left;color:var(--text-main);cursor:pointer;transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease}.level-card.active{border-color:#38572d40;background:#fff}.level-card.disabled{opacity:.76}.level-code{margin:0;color:var(--accent-strong);font-size:1.35rem;font-weight:800}.level-desc{margin:6px 0 0;color:var(--text-muted);font-size:.88rem;line-height:1.4}.level-meta{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px;color:var(--accent-strong);font-size:.8rem;font-weight:700}.level-badge{position:absolute;top:10px;right:10px;padding:4px 8px;border-radius:999px;background:#567a471a;color:var(--accent-strong);font-size:.7rem;font-weight:700}.section-heading{display:flex;align-items:flex-end;justify-content:space-between;gap:12px;margin-bottom:12px}.section-kicker{margin:0 0 4px;color:var(--accent);font-size:.8rem;font-weight:800;letter-spacing:.08em;text-transform:uppercase}.section-heading h2,.coming-soon-panel h2{margin:0;color:var(--accent-strong);font-size:clamp(1.2rem,3vw,1.6rem)}.coming-soon-panel p{margin:10px 0 0;color:var(--text-muted);line-height:1.7}.compact-stats{margin-top:0}.topics-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.topic-category-card{display:flex;min-height:132px;padding:14px;border-radius:14px;text-decoration:none;flex-direction:column;justify-content:space-between;gap:14px;transition:background .2s ease,border-color .2s ease}.topic-category-card:hover,.topic-category-card:focus-visible,.nav-button:hover,.nav-button:focus-visible,.card-shell:focus-visible{outline:none;transform:none;box-shadow:none}.topic-card-body{display:flex;flex-direction:column;gap:8px}.topic-parent,.topic-parent-inline,.topic-zh,.topic-zh-inline,.translation-line,.meta-empty{margin:0;color:var(--text-muted)}.topic-parent,.topic-parent-inline{font-size:.76rem;font-weight:700;letter-spacing:.03em}.topic-category-card h2{margin:0;font-size:clamp(1rem,3vw,1.18rem);line-height:1.3;color:var(--accent-strong)}.topic-zh,.topic-zh-inline{font-size:.84rem;line-height:1.4}.topic-card-meta{display:flex;align-items:center;justify-content:space-between;color:var(--accent-strong);font-size:.84rem;font-weight:700}.topic-page-shell{min-height:100dvh;display:flex;flex-direction:column;gap:0;padding:8px 8px calc(10px + env(safe-area-inset-bottom))}.topic-topbar,.status-row{display:flex;align-items:center;justify-content:space-between;gap:8px}.flashcard-panel{display:flex;flex:1;min-height:0;flex-direction:column;gap:8px;padding:4px 2px 8px;border:0;box-shadow:none}.status-row{min-height:20px;padding:2px 6px 0}.compact-back-link{color:#243121bd;font-size:.84rem;font-weight:600;text-decoration:none}.card-shell{-moz-appearance:none;appearance:none;-webkit-appearance:none;-webkit-tap-highlight-color:transparent;touch-action:manipulation;-webkit-user-select:none;user-select:none;display:block;width:100%;flex:1;min-height:76dvh;height:clamp(580px,76dvh,860px);border:0;background:transparent;border-radius:14px;padding:0;cursor:pointer;box-shadow:none;outline:none;overflow:hidden}.card-surface{position:relative;height:100%;border-radius:14px;padding:34px 28px 28px;overflow:hidden;transition:background .2s ease,border-color .2s ease;box-shadow:none;display:flex;isolation:isolate;contain:layout paint;transform:translateZ(0);-webkit-transform:translateZ(0);backface-visibility:hidden;-webkit-backface-visibility:hidden}.card-front{background:var(--card-front)}.card-back{background:var(--card-back)}.card-front-content,.card-back-content{min-height:100%;width:100%;transform:translateZ(0);-webkit-transform:translateZ(0);backface-visibility:hidden;-webkit-backface-visibility:hidden}.card-front-content{display:flex;flex-direction:column;justify-content:center;gap:40px;text-align:left;padding-top:0}.word-heading{margin:0;color:var(--accent-strong);font-size:clamp(2.15rem,6vw,2.95rem);line-height:1.18;font-weight:800;letter-spacing:-.018em}.example-sentence{margin:0;font-size:clamp(1.22rem,4.4vw,1.54rem);line-height:1.82;text-align:left;color:var(--text-body)}.example-sentence+.example-sentence{margin-top:14px}.card-back-content{display:flex;flex-direction:column;justify-content:flex-start;gap:24px;padding-top:8px}.detail-stream{display:flex;flex-direction:column;gap:10px}.compact-stream{padding-top:0;border-top:0}.detail-label{margin:0;color:var(--text-tertiary);font-size:.8rem;font-weight:700;text-transform:none;letter-spacing:.03em}.meaning-line,.translation-line{margin:0;font-size:1.12rem;line-height:1.76}.meaning-line{color:var(--text-main)}.meaning-line strong{color:var(--text-main);font-weight:800}.translation-line-compact{color:var(--text-secondary);font-size:.96rem;line-height:1.76}.translation-line-compact+.translation-line-compact{margin-top:6px}.meaning-zh{color:var(--text-secondary);font-weight:600;font-size:.94em}.synonym-list{margin:0;padding-left:1.1rem;line-height:1.78;font-size:1.04rem;color:var(--text-body)}.synonym-list li+li{margin-top:8px}.back-example{text-align:left;font-size:1.16rem;line-height:1.8}.back-example+.back-example{margin-top:14px}.target-highlight{font-weight:800;text-decoration:underline;text-decoration-thickness:2px;text-underline-offset:.16em;text-decoration-color:var(--accent-soft);color:var(--accent-deep)}.controls{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;position:sticky;bottom:8px;padding-top:4px;background:linear-gradient(180deg,#fff0,#ffffffeb 22%,#fffffffa)}.nav-button{border:1px solid var(--accent-border);border-radius:999px;padding:10px 12px;background:#fff;color:var(--accent-strong);font-weight:700;text-decoration:none;text-align:center;cursor:pointer;transition:transform .2s ease,box-shadow .2s ease,background .2s ease}.nav-button.primary{background:var(--accent-strong);color:#fff}.nav-button.ghost{background:#fff}.nav-button.compact-back{padding:7px 10px;font-size:.82rem;white-space:nowrap}@media(min-width:720px){.page-shell{padding:36px 20px 56px}.level-grid,.topics-grid{grid-template-columns:repeat(3,minmax(0,1fr))}}@media(max-width:719px){.section-heading{flex-direction:column;align-items:flex-start}.topics-grid{grid-template-columns:repeat(1,minmax(0,1fr))}}.hero-subtitle{margin:12px auto 0;max-width:760px;color:var(--text-muted);font-size:.98rem;line-height:1.7}.install-hint{margin:0;color:var(--text-muted);font-size:.84rem;font-weight:600}.level-link{text-decoration:none}.level-link:hover,.level-link:focus-visible,.level-card:hover,.level-card:focus-visible{border-color:#38572d40}.level-page-shell{padding-top:24px}.level-hero,.home-hero{margin-bottom:18px}.level-back-link{display:inline-block;margin-bottom:12px}