:root{--color-bg: #fbf6ed;--color-surface: #fffdf8;--color-text: #45362a;--color-muted: #7d6e61;--color-border: #eee3d5;--color-sage: #dfeccd;--color-green: #6e9a4f;--color-coral: #ef735e;--color-pinyin: #ffd8c8;--color-math: #d4eafa;--color-english: #f6e4aa;--color-review: #e6d9f2;--shadow-soft: 0 12px 30px rgb(79 59 39 / 10%);--radius-md: 18px;--radius-lg: 26px;--space-1: 4px;--space-2: 8px;--space-3: 12px;--space-4: 16px;--space-5: 20px;--space-6: 24px;--space-8: 32px;--content-max: 1180px;--nav-height: 74px}*{box-sizing:border-box}html{color-scheme:light;background:var(--color-bg)}body{margin:0;min-width:320px;min-height:100vh;color:var(--color-text);background:var(--color-bg);font-family:ui-rounded,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif;-webkit-font-smoothing:antialiased}button,a{font:inherit}button,a{-webkit-tap-highlight-color:transparent}:focus-visible{outline:3px solid #337ebf;outline-offset:3px}.app-shell{min-height:100dvh;padding-bottom:calc(var(--nav-height) + env(safe-area-inset-bottom))}.app-main{width:min(100%,var(--content-max));margin:0 auto}.bottom-nav{position:fixed;inset:auto 0 0;z-index:20;display:grid;grid-template-columns:repeat(4,1fr);min-height:var(--nav-height);padding:8px max(12px,env(safe-area-inset-right)) calc(8px + env(safe-area-inset-bottom)) max(12px,env(safe-area-inset-left));border-top:1px solid var(--color-border);background:#fffdf8f0;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px)}.bottom-nav__item{display:flex;min-width:0;min-height:52px;flex-direction:column;align-items:center;justify-content:center;gap:2px;border-radius:14px;color:var(--color-muted);font-size:12px;font-weight:700;text-decoration:none}.bottom-nav__item[aria-current=page]{color:var(--color-coral);background:#fff3ed}.bottom-nav__icon{width:24px;height:24px;object-fit:contain;transition:transform .18s ease,filter .18s ease}.bottom-nav__item[aria-current=page] .bottom-nav__icon{filter:drop-shadow(0 3px 5px rgb(107 68 45 / 18%));transform:translateY(-1px) scale(1.04)}@media(min-width:1024px)and (orientation:landscape){.app-shell{padding-bottom:0;padding-left:94px}.bottom-nav{inset:0 auto 0 0;width:94px;min-height:100vh;grid-template-columns:1fr;align-content:center;gap:12px;border-top:0;border-right:1px solid var(--color-border)}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{scroll-behavior:auto!important;animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}}