:root{--color-bg: #ffffff;--color-bg-secondary: #f8f9fa;--color-text: #1a1a2e;--color-text-secondary: #6c757d;--color-primary: #0d9488;--color-primary-hover: #0f766e;--color-border: #e9ecef;--color-card-bg: #ffffff;--shadow-sm: 0 1px 2px rgba(0, 0, 0, .05);--shadow-md: 0 4px 6px rgba(0, 0, 0, .07);--shadow-lg: 0 10px 15px rgba(0, 0, 0, .1);--font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, sans-serif;--font-serif: Georgia, "Times New Roman", serif;--max-width: 1200px;--content-width: 720px}[data-theme=dark]{--color-bg: #1a1a2e;--color-bg-secondary: #16213e;--color-text: #e8e8e8;--color-text-secondary: #a0a0a0;--color-primary: #14b8a6;--color-primary-hover: #2dd4bf;--color-border: #2d2d44;--color-card-bg: #16213e;--shadow-sm: 0 1px 2px rgba(0, 0, 0, .2);--shadow-md: 0 4px 6px rgba(0, 0, 0, .3);--shadow-lg: 0 10px 15px rgba(0, 0, 0, .4)}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth}body{font-family:var(--font-sans);font-size:16px;line-height:1.6;color:var(--color-text);background-color:var(--color-bg);transition:background-color .3s,color .3s}a{color:var(--color-primary);text-decoration:none;transition:color .2s}a:hover{color:var(--color-primary-hover)}h1,h2,h3,h4{font-family:var(--font-serif);font-weight:700;line-height:1.3;margin-bottom:1rem}h1{font-size:2.5rem}h2{font-size:1.75rem}h3{font-size:1.25rem}p{margin-bottom:1rem}ul,ol{margin-bottom:1rem;padding-left:1.5rem}li{margin-bottom:.5rem}.header{position:sticky;top:0;background:var(--color-bg);border-bottom:1px solid var(--color-border);z-index:100;padding:1rem 0}.header-container{max-width:var(--max-width);margin:0 auto;padding:0 1.5rem;display:flex;align-items:center;justify-content:space-between;gap:2rem}.logo{font-family:var(--font-serif);font-size:1.5rem;font-weight:700;color:var(--color-text)}.logo:hover{color:var(--color-primary)}.nav{display:flex;gap:1.5rem}.nav a{color:var(--color-text);font-weight:500}.nav a:hover{color:var(--color-primary)}.header-right{display:flex;align-items:center;gap:1rem}.theme-toggle{background:none;border:none;cursor:pointer;padding:.5rem;color:var(--color-text);display:flex;align-items:center}.theme-toggle:hover{color:var(--color-primary)}[data-theme=light] .moon-icon,[data-theme=dark] .sun-icon{display:none}main{min-height:calc(100vh - 200px)}.hero{background:var(--color-bg-secondary);padding:5rem 1.5rem;text-align:center}.hero-content{max-width:var(--content-width);margin:0 auto}.hero h1{font-size:3rem;margin-bottom:1.5rem}.hero-subtitle{font-size:1.25rem;color:var(--color-text-secondary);margin-bottom:2rem}.hero-cta{display:flex;flex-direction:column;align-items:center;gap:1.5rem}.btn{display:inline-block;padding:.75rem 1.5rem;border-radius:6px;font-weight:600;text-align:center;transition:all .2s;cursor:pointer;border:none}.btn-primary{background:var(--color-primary);color:#fff}.btn-primary:hover{background:var(--color-primary-hover);color:#fff}.social-links{display:flex;gap:1rem}.social-links a{color:var(--color-text-secondary);transition:color .2s,transform .2s}.social-links a:hover{color:var(--color-primary);transform:translateY(-2px)}.social-links--large{gap:1.5rem}.featured-tips,.tips-page,.related-tips{max-width:var(--max-width);margin:0 auto;padding:4rem 1.5rem}.section-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:2rem}.view-all{font-weight:500}.tips-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:1.5rem}.tip-card{background:var(--color-card-bg);border:1px solid var(--color-border);border-radius:12px;overflow:hidden;transition:box-shadow .2s,transform .2s}.tip-card:hover{box-shadow:var(--shadow-md);transform:translateY(-2px)}.tip-card-link{display:block;padding:1.5rem;color:inherit}.tip-category{display:inline-block;font-size:.75rem;font-weight:600;text-transform:uppercase;letter-spacing:.5px;padding:.25rem .75rem;border-radius:20px;margin-bottom:.75rem}.tip-category--confused-words{background:#fef3c7;color:#92400e}.tip-category--grammar{background:#dbeafe;color:#1e40af}.tip-category--vocabulary{background:#d1fae5;color:#065f46}.tip-category--writing-style{background:#ede9fe;color:#5b21b6}[data-theme=dark] .tip-category--confused-words{background:#78350f;color:#fef3c7}[data-theme=dark] .tip-category--grammar{background:#1e3a8a;color:#dbeafe}[data-theme=dark] .tip-category--vocabulary{background:#064e3b;color:#d1fae5}[data-theme=dark] .tip-category--writing-style{background:#4c1d95;color:#ede9fe}.tip-title{font-size:1.25rem;margin-bottom:.5rem}.tip-description{color:var(--color-text-secondary);font-size:.95rem;margin-bottom:1rem}.tip-read-more{color:var(--color-primary);font-weight:500}.tips-intro{color:var(--color-text-secondary);margin-bottom:2rem}.category-filter{display:flex;flex-wrap:wrap;gap:.5rem;margin-bottom:2rem}.filter-btn{padding:.5rem 1rem;border:1px solid var(--color-border);border-radius:20px;background:var(--color-bg);color:var(--color-text);cursor:pointer;transition:all .2s}.filter-btn:hover,.filter-btn.active{background:var(--color-primary);border-color:var(--color-primary);color:#fff}.follow-cta{background:var(--color-bg-secondary);padding:4rem 1.5rem;text-align:center}.follow-cta h2{margin-bottom:.5rem}.follow-cta p{color:var(--color-text-secondary);margin-bottom:1.5rem}.follow-cta .social-links{justify-content:center}.page-content{max-width:var(--content-width);margin:0 auto;padding:4rem 1.5rem}.page-content h1{margin-bottom:2rem}.page-content section{margin-bottom:3rem}.contact-intro{font-size:1.1rem;margin-bottom:2rem}.contact-form{margin-bottom:3rem}.form-group{margin-bottom:1.5rem}.form-group label{display:block;font-weight:500;margin-bottom:.5rem}.form-group input,.form-group select,.form-group textarea{width:100%;padding:.75rem;border:1px solid var(--color-border);border-radius:6px;background:var(--color-bg);color:var(--color-text);font-size:1rem;font-family:inherit}.form-group input:focus,.form-group select:focus,.form-group textarea:focus{outline:none;border-color:var(--color-primary);box-shadow:0 0 0 3px #0d94881a}.hidden{display:none}.contact-social{text-align:center;padding-top:2rem;border-top:1px solid var(--color-border)}.contact-social .social-links{justify-content:center;margin-top:1rem}.tip-article{max-width:var(--content-width);margin:0 auto;padding:2rem 1.5rem 4rem}.tip-header{margin-bottom:2rem}.back-link{display:inline-block;margin-bottom:1rem;color:var(--color-text-secondary)}.back-link:hover{color:var(--color-primary)}.tip-header h1{font-size:2.25rem;margin-top:1rem}.tip-meta{color:var(--color-text-secondary);font-size:.9rem}.tip-content{font-size:1.1rem;line-height:1.8}.tip-content h2{margin-top:2.5rem;padding-top:1.5rem;border-top:1px solid var(--color-border)}.tip-content h2:first-child{margin-top:0;padding-top:0;border-top:none}.tip-content strong{color:var(--color-primary)}.tip-content code{background:var(--color-bg-secondary);padding:.2rem .4rem;border-radius:4px;font-size:.9em}.tip-content table{width:100%;border-collapse:collapse;margin:1.5rem 0}.tip-content th,.tip-content td{padding:.75rem;border:1px solid var(--color-border);text-align:left}.tip-content th{background:var(--color-bg-secondary);font-weight:600}.tip-footer{margin-top:3rem;padding-top:2rem;border-top:1px solid var(--color-border)}.share-section,.follow-section{margin-bottom:2rem}.share-section p,.follow-section p{margin-bottom:1rem;font-weight:500}.share-btn{display:inline-block;padding:.5rem 1rem;background:var(--color-bg-secondary);border-radius:6px;font-weight:500}.share-btn:hover{background:var(--color-primary);color:#fff}.related-tips{border-top:1px solid var(--color-border)}.related-tips h2{margin-bottom:1.5rem}.footer{background:var(--color-bg-secondary);padding:3rem 1.5rem 1.5rem;margin-top:auto}.footer-container{max-width:var(--max-width);margin:0 auto;display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:2rem;margin-bottom:2rem}.footer-logo{font-family:var(--font-serif);font-size:1.25rem;font-weight:700}.footer-tagline{color:var(--color-text-secondary);margin-top:.5rem}.footer-links h4,.footer-social h4{font-size:1rem;margin-bottom:1rem}.footer-links nav{display:flex;flex-direction:column;gap:.5rem}.footer-links a{color:var(--color-text-secondary)}.footer-links a:hover{color:var(--color-primary)}.footer-bottom{text-align:center;padding-top:1.5rem;border-top:1px solid var(--color-border);color:var(--color-text-secondary);font-size:.9rem}@media (max-width: 768px){.header-container{flex-wrap:wrap}.nav{order:3;width:100%;justify-content:center;padding-top:1rem;border-top:1px solid var(--color-border);margin-top:1rem}.hero h1{font-size:2rem}.tips-grid{grid-template-columns:1fr}h1{font-size:2rem}h2{font-size:1.5rem}}