:root{--color-midnight: #1A1D2E;--color-blue: #2D5BFF;--color-gold: #E8A838;--color-jade: #E8F0EA;--color-bg: #F7F8FA;--color-surface: #FFFFFF;--color-text-secondary: #6B7280;--color-border: #E5E7EB;--color-cinnabar: #E05545;--color-bamboo: #34A853;--color-blue-glow: rgba(45, 91, 255, .3);--color-blue-soft: rgba(45, 91, 255, .1);--color-blue-hover: #1a4aee;--color-midnight-80: rgba(26, 29, 46, .8);--color-midnight-95: rgba(26, 29, 46, .95);--font-heading: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;--font-body: "Source Sans 3", "Source Sans Pro", sans-serif;--font-chinese: "Noto Sans SC", sans-serif;--font-mono: "JetBrains Mono", monospace;--text-hero: clamp(36px, 5vw, 64px);--text-h1: clamp(28px, 4vw, 40px);--text-h2: clamp(24px, 3vw, 32px);--text-h3: clamp(20px, 2.5vw, 24px);--text-body-lg: 18px;--text-body: 16px;--text-caption: 14px;--text-small: 12px;--space-xs: 4px;--space-sm: 8px;--space-md: 16px;--space-lg: 24px;--space-xl: 32px;--space-2xl: 48px;--space-3xl: 64px;--space-4xl: 96px;--space-5xl: 128px;--container-max: 1200px;--container-padding: clamp(16px, 4vw, 40px);--section-padding: clamp(64px, 10vw, 128px);--nav-height: 72px;--border-radius: 8px;--border-radius-lg: 16px;--border-radius-xl: 24px;--glass-bg: rgba(26, 29, 46, .8);--glass-blur: 20px;--shadow-sm: 0 1px 3px rgba(0, 0, 0, .06);--shadow-md: 0 4px 12px rgba(0, 0, 0, .08);--shadow-lg: 0 8px 32px rgba(0, 0, 0, .12);--shadow-glow: 0 0 30px var(--color-blue-glow);--ease-out: cubic-bezier(.16, 1, .3, 1);--ease-spring: cubic-bezier(.34, 1.56, .64, 1);--duration-fast: .15s;--duration-normal: .3s;--duration-slow: .6s}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth;-webkit-text-size-adjust:100%;text-size-adjust:100%;overflow-x:hidden}body{min-height:100vh;line-height:1.6;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;text-rendering:optimizeLegibility}img,picture,video,canvas,svg{display:block;max-width:100%}input,button,textarea,select{font:inherit;color:inherit}button{cursor:pointer;border:none;background:none}a{color:inherit;text-decoration:none}ul,ol{list-style:none}h1,h2,h3,h4,h5,h6{overflow-wrap:break-word;line-height:1.2}p{overflow-wrap:break-word}body{font-family:var(--font-body);font-size:var(--text-body);font-weight:400;color:var(--color-midnight);background-color:var(--color-bg);overflow-x:hidden}h1,h2,h3,h4{font-family:var(--font-heading);color:var(--color-midnight)}h1{font-size:var(--text-hero);font-weight:700}h2{font-size:var(--text-h2);font-weight:600}h3{font-size:var(--text-h3);font-weight:600}.text-lg{font-size:var(--text-body-lg)}.text-secondary{color:var(--color-text-secondary)}.text-caption{font-size:var(--text-caption)}.chinese{font-family:var(--font-chinese);font-size:120%}.pinyin{font-family:var(--font-mono);font-size:var(--text-caption)}.mono{font-family:var(--font-mono)}a:hover{color:var(--color-blue)}::selection{background-color:var(--color-blue);color:var(--color-surface)}.container{max-width:var(--container-max);margin:0 auto;padding:0 var(--container-padding)}.section,.features,.ai-demo,.process,.audience,.quiz,.pricing,.character,.faq{padding:var(--section-padding) 0}.section--dark{background-color:var(--color-midnight);color:var(--color-surface)}.section--light{background-color:var(--color-bg)}.section--white{background-color:var(--color-surface)}.section__header{text-align:center;margin-bottom:var(--space-3xl)}.section__label{font-family:var(--font-mono);font-size:var(--text-caption);color:var(--color-gold);letter-spacing:3px;text-transform:uppercase;margin-bottom:var(--space-md);display:block}.section__title{font-size:var(--text-h2);font-weight:600;margin-bottom:var(--space-md)}.section__subtitle{font-size:var(--text-body-lg);color:var(--color-text-secondary);max-width:600px;margin:0 auto}.section--dark .section__title{color:var(--color-surface)}.section--dark .section__subtitle{color:#9ca3af}.grid{display:grid;gap:var(--space-lg)}.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}@media(min-width:768px){.grid-2,.grid-3,.grid-4{grid-template-columns:repeat(2,1fr)}}@media(min-width:1024px){.grid-3{grid-template-columns:repeat(3,1fr)}.grid-4{grid-template-columns:repeat(4,1fr)}}.flex{display:flex}.flex-center{display:flex;align-items:center;justify-content:center}.flex-between{display:flex;align-items:center;justify-content:space-between}.flex-col{display:flex;flex-direction:column}.gap-sm{gap:var(--space-sm)}.gap-md{gap:var(--space-md)}.gap-lg{gap:var(--space-lg)}.gap-xl{gap:var(--space-xl)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:var(--space-sm);padding:14px 32px;border-radius:var(--border-radius);font-family:var(--font-heading);font-weight:600;font-size:var(--text-body);line-height:1;transition:all var(--duration-normal) var(--ease-out);white-space:nowrap;position:relative;overflow:hidden}.btn--primary{background-color:var(--color-blue);color:var(--color-surface);box-shadow:var(--shadow-glow)}.btn--primary:hover{background-color:var(--color-blue-hover);box-shadow:0 0 40px var(--color-blue-glow);transform:translateY(-2px)}.btn:focus-visible{outline:2px solid var(--color-blue);outline-offset:2px}.btn--secondary{background-color:transparent;color:var(--color-surface);border:2px solid var(--color-surface)}.btn--secondary:hover{background-color:#ffffff1a;transform:translateY(-2px)}.btn--outline{background-color:transparent;color:var(--color-blue);border:2px solid var(--color-blue)}.btn--outline:hover{background-color:var(--color-blue-soft);transform:translateY(-2px)}.btn--white{background-color:var(--color-surface);color:var(--color-blue)}.btn--white:hover{box-shadow:0 0 30px #ffffff4d;transform:translateY(-2px)}.btn--sm{padding:10px 20px;font-size:var(--text-caption)}.btn--lg{padding:18px 40px;font-size:var(--text-body-lg)}.card{background-color:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--border-radius-lg);padding:var(--space-xl);transition:all var(--duration-normal) var(--ease-out);position:relative;overflow:hidden}.card:hover{border-color:var(--color-blue);box-shadow:0 0 20px var(--color-blue-soft);transform:translateY(-4px)}.card:before{content:"";position:absolute;top:0;left:0;width:100%;height:100%;background:linear-gradient(90deg,transparent,rgba(45,91,255,.03),transparent);transform:translate(-100%);transition:transform var(--duration-slow) var(--ease-out);pointer-events:none}.card:hover:before{transform:translate(100%)}.badge{display:inline-flex;align-items:center;padding:4px 12px;border-radius:100px;font-family:var(--font-heading);font-weight:600;font-size:var(--text-small);line-height:1}.badge--gold{background-color:var(--color-gold);color:var(--color-midnight)}.badge--blue{background-color:var(--color-blue);color:var(--color-surface)}.badge--jade{background-color:var(--color-jade);color:var(--color-midnight)}.glass{background:#ffffff0d;backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border:1px solid rgba(255,255,255,.1);border-radius:var(--border-radius-lg)}.icon-box{width:48px;height:48px;display:flex;align-items:center;justify-content:center;border-radius:var(--border-radius);background-color:var(--color-blue-soft);color:var(--color-blue);flex-shrink:0}.icon-box svg{width:24px;height:24px;stroke:currentColor;stroke-width:2;fill:none;stroke-linecap:round;stroke-linejoin:round}.check-list{display:flex;flex-direction:column;gap:var(--space-sm)}.check-list li{display:flex;align-items:flex-start;gap:var(--space-sm);font-size:var(--text-body)}.check-list li:before{content:"✓";color:var(--color-bamboo);font-weight:700;flex-shrink:0}.check-list--dark li:before{color:var(--color-bamboo)}