body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Fira Sans,Droid Sans,Helvetica Neue,sans-serif;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}code{font-family:source-code-pro,Menlo,Monaco,Consolas,Courier New,monospace}:root{--bg-color: #f8f9fa;--text-color: #212529;--calculator-bg: #ffffff;--button-bg: #e9ecef;--button-hover: #dee2e6;--op-button-bg: #fd7e14;--op-button-hover: #e8590c;--display-bg: #212529;--display-text: #51cf66;--history-bg: #ffffff;--nav-bg: #ffffff;--accent-color: #339af0;--footer-text: #868e96}[data-theme=dark]{--bg-color: #121212;--text-color: #e9ecef;--calculator-bg: #1e1e1e;--button-bg: #2d2d2d;--button-hover: #3d3d3d;--op-button-bg: #f76707;--op-button-hover: #d9480f;--display-bg: #000000;--display-text: #63e6be;--history-bg: #1e1e1e;--nav-bg: #1e1e1e}body{margin:0;background-color:var(--bg-color);color:var(--text-color);font-family:Pretendard,-apple-system,BlinkMacSystemFont,system-ui,Roboto,sans-serif;transition:all .3s ease}.layout{max-width:1000px;margin:0 auto;padding:20px;min-height:100vh;display:flex;flex-direction:column}nav{display:flex;justify-content:space-between;align-items:center;padding:15px 20px;background-color:var(--nav-bg);border-radius:12px;margin-bottom:30px;box-shadow:0 2px 10px #0000000d}.nav-links button{background:none;border:none;color:var(--text-color);font-size:1rem;font-weight:600;margin:0 5px;cursor:pointer;padding:8px 15px;border-radius:6px;transition:.2s}.nav-links button.active{background-color:var(--accent-color);color:#fff}.container{display:flex;gap:30px;flex-wrap:wrap;justify-content:center;flex:1}.main-content{flex:1;min-width:350px}.calculator{background-color:var(--calculator-bg);padding:25px;border-radius:24px;box-shadow:0 12px 40px #0000001f}.display{background-color:var(--display-bg);color:var(--display-text);padding:20px;border-radius:15px;text-align:right;margin-bottom:25px;min-height:100px;display:flex;flex-direction:column;justify-content:center}.expression{font-size:1rem;opacity:.7;margin-bottom:5px}.result{font-size:2.2rem;font-weight:700;word-break:break-all}.buttons{display:grid;grid-template-columns:repeat(5,1fr);gap:12px}button{border:none;padding:18px 10px;border-radius:12px;font-size:1.1rem;font-weight:600;cursor:pointer;background-color:var(--button-bg);color:var(--text-color);transition:.15s}button:hover{background-color:var(--button-hover)}button.operator{background-color:var(--op-button-bg);color:#fff}.info-section{margin-top:40px;padding:35px;background-color:var(--calculator-bg);border-radius:20px;line-height:1.8;box-shadow:0 4px 20px #0000000d}.info-section h3{margin-top:0;color:var(--accent-color);font-size:1.5rem}.info-section p{margin-bottom:1.2rem}.history{width:280px;background-color:var(--history-bg);padding:20px;border-radius:20px;box-shadow:0 4px 15px #0000000d}footer{margin-top:50px;padding:40px 20px;border-top:1px solid var(--button-bg);text-align:center;color:var(--footer-text)}.footer-links{margin-bottom:20px}.footer-links button{background:none;border:none;color:var(--accent-color);margin:0 10px;font-size:.9rem;font-weight:400}.footer-links button:hover{text-decoration:underline}.legal-content{background-color:var(--calculator-bg);padding:40px;border-radius:24px;line-height:1.8;text-align:left}.legal-content h2{color:var(--accent-color)}@media(max-width:800px){.container{flex-direction:column;align-items:center}.history{width:100%}}