:root {
            --primary: #7984b9;
            --primary-dark: #586dce;
            --primary-light: #4895ef;
            --secondary: #6194ac;
            --accent: #f72585;
            --dark: #1a1f36;
            --dark-light: #2d3748;
            --light: #ffffff;
            --gray: #a0aec0;
            --light-gray: #f7fafc;
            --success: #38b2ac;
            --warning: #ed8936;
            --card-bg: rgba(255, 255, 255, 0.08);
            --card-border: rgba(255, 255, 255, 0.12);
            --glass-bg: rgba(255, 255, 255, 0.05);
            --glass-border: rgba(255, 255, 255, 0.1);
            --border-radius: 16px;
            --border-radius-sm: 10px;
            --shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            --shadow-light: 0 10px 20px rgba(0, 0, 0, 0.06);
            --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
            --gradient-primary: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
            --gradient-dark: linear-gradient(135deg, var(--dark) 0%, var(--dark-light) 100%);
            --gradient-accent: linear-gradient(135deg, var(--accent) 0%, var(--secondary) 100%);
        }
        
        /* Light mode variables */
        .light-mode {
            --dark: #f8fafc;
            --dark-light: #e2e8f0;
            --light: #1a202c;
            --gray: #718096;
            --light-gray: #1a202c;
            --card-bg: rgba(255, 255, 255, 0.9);
            --card-border: rgba(0, 0, 0, 0.1);
            --glass-bg: rgba(255, 255, 255, 0.8);
            --glass-border: rgba(0, 0, 0, 0.1);
            --shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
            --shadow-light: 0 10px 20px rgba(0, 0, 0, 0.04);
            --gradient-dark: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
        }
        
        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            font-family: 'Plus Jakarta Sans', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background: var(--gradient-dark);
            color: var(--light);
            min-height: 100vh;
            line-height: 1.6;
            overflow-x: hidden;
            transition: var(--transition);
        }
        
        .container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 20px;
        }
        
        /* Theme Toggle */
        .theme-toggle {
            position: absolute;
            top: 30px;
            right: 30px;
            z-index: 100;
        }
        
        .theme-toggle-btn {
            border: 1px solid var(--glass-border);
            color: var(--light);
            width: 50px;
            height: 50px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: var(--transition);
            backdrop-filter: blur(10px);
            font-size: 1.2rem;
            box-shadow: var(--shadow-light);
        }
        
        .theme-toggle-btn:hover {
            transform: scale(1.1);
            box-shadow: var(--shadow);
        }
        
        /* Hero Section */
        .hero {
            text-align: center;
            padding: 40px 0;
            margin-bottom: 40px;
            position: relative;
        }
        
        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" preserveAspectRatio="none"><path d="M0,0 L100,0 L100,100 Z" fill="rgba(255,255,255,0.03)"/></svg>');
            background-size: cover;
            z-index: -1;
        }
        
        .light-mode .hero::before {
            background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" preserveAspectRatio="none"><path d="M0,0 L100,0 L100,100 Z" fill="rgba(0,0,0,0.03)"/></svg>');
        }
        
        .hero h1 {
            font-size: 3.5rem;
            font-weight: 800;
            margin-bottom: 20px;
            background: linear-gradient(to right, var(--light), var(--primary-light));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            line-height: 1.2;
        }
        
        .hero p {
            font-size: 1.3rem;
            max-width: 700px;
            margin: 0 auto 30px;
            color: var(--gray);
            font-weight: 400;
        }
        
        .hero-badges {
            display: flex;
            justify-content: center;
            gap: 15px;
            flex-wrap: wrap;
        }
        
        .hero-badge {
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            padding: 10px 20px;
            border-radius: 50px;
            font-size: 0.9rem;
            font-weight: 500;
            backdrop-filter: blur(10px);
            display: flex;
            align-items: center;
            gap: 8px;
        }
        
        /* Navigation Tabs */
        .nav-tabs-container {
            margin-bottom: 40px;
            position: relative;
        }
        
        .nav-tabs {
            display: flex;
            justify-content: center;
            gap: 10px;
            flex-wrap: wrap;
            background: var(--glass-bg);
            border-radius: var(--border-radius);
            padding: 10px;
            backdrop-filter: blur(10px);
            border: 1px solid var(--glass-border);
            
        }
        
        .nav-tab {
           
            border: none;
            padding: 16px 24px;
            border-radius: var(--border-radius-sm);
            cursor: pointer;
            transition: var(--transition);
            font-size: 1rem;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 12px;
            position: relative;
            overflow: hidden;
        }
        
        .nav-tab::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: var(--gradient-primary);
            opacity: 0;
            transition: var(--transition);
            z-index: -1;
        }
        
        .nav-tab:hover::before {
            opacity: 0.1;
        }
        
        .nav-tab.active {
            background: var(--gradient-primary);
            box-shadow: var(--shadow);
        }
        
        .nav-tab.active::before {
            opacity: 1;
        }
        
        /* Calculator Containers */
        .calculator-container {
            display: none;
            background: var(--glass-bg);
            border-radius: var(--border-radius);
            padding: 30px;
            box-shadow: var(--shadow);
            margin-bottom: 30px;
            border: 1px solid var(--glass-border);
            backdrop-filter: blur(10px);
            animation: fadeIn 0.5s ease;
        }
        
        .calculator-container.active {
            display: block;
        }
        
        .calculator-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 30px;
            padding-bottom: 20px;
            border-bottom: 1px solid var(--glass-border);
        }
        
        .calculator-title {
            font-size: 2rem;
            font-weight: 700;
            color: var(--light);
            display: flex;
            align-items: center;
            gap: 12px;
        }
        
        .calculator-badge {
            background: var(--gradient-accent);
            color: white;
            padding: 8px 16px;
            border-radius: 50px;
            font-size: 0.85rem;
            font-weight: 600;
            box-shadow: var(--shadow-light);
        }
        
        .calculator-content {
            display: grid;
            grid-template-columns: 1fr 2fr;
            gap: 30px;
        }
        
        /* Shape Selector */
        .shape-selector {
            background: var(--glass-bg);
            border-radius: var(--border-radius);
            padding: 25px;
            border: 1px solid var(--glass-border);
            max-height: 600px;
            overflow-y: auto;
        }
        
        .shape-selector h3 {
            margin-bottom: 20px;
            color: var(--light);
            font-size: 1.3rem;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 10px;
        }
        
        .shape-list {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
            gap: 15px;
            max-height: 500px;
            overflow-y: auto;
            padding-right: 10px;
        }
        
        .shape-list::-webkit-scrollbar {
            width: 6px;
        }
        
        .shape-list::-webkit-scrollbar-track {
            background: rgba(255, 255, 255, 0.05);
            border-radius: 10px;
        }
        
        .shape-list::-webkit-scrollbar-thumb {
            background: var(--primary);
            border-radius: 10px;
        }
        
        .shape-item {
            padding: 18px 12px;
            text-align: center;
            background: var(--glass-bg);
            border-radius: var(--border-radius-sm);
            cursor: pointer;
            transition: var(--transition);
            border: 1px solid var(--glass-border);
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 10px;
        }
        
        .shape-item:hover {
            transform: translateY(-5px);
            border-color: var(--primary);
            box-shadow: var(--shadow-light);
        }
        
        .shape-item.active {
            background: var(--gradient-primary);
            border-color: var(--primary);
            box-shadow: var(--shadow);
        }
        
        .shape-icon {
            font-size: 32px;
            height: 40px;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .shape-name {
            font-weight: 500;
            font-size: 0.9rem;
        }
        
        /* Calculator Main */
        .calculator-main {
            display: flex;
            flex-direction: column;
        }
        
        .calculator-visual {
            display: flex;
            align-items: center;
            justify-content: space-between;
            margin-bottom: 30px;
            background: var(--glass-bg);
            border-radius: var(--border-radius);
            padding: 25px;
            border: 1px solid var(--glass-border);
        }
        
        .shape-diagram {
            font-size: 120px;
            color: var(--primary-light);
            text-align: center;
            flex: 1;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .formula-card {
            flex: 1;
            background: var(--glass-bg);
            padding: 20px;
            border-radius: var(--border-radius-sm);
            border-left: 4px solid var(--primary);
        }
        
        .formula-card h4 {
            margin-bottom: 12px;
            color: var(--light);
            font-size: 1.1rem;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        
        .formula {
            font-family: 'Courier New', monospace;
            font-size: 1.2rem;
            color: var(--light);
            background: rgba(0, 0, 0, 0.2);
            padding: 12px;
            border-radius: 8px;
            border: 1px solid var(--glass-border);
        }
        
        .light-mode .formula {
            background: rgba(0, 0, 0, 0.05);
        }
        
        /* Calculator Inputs */
        .calculator-inputs {
            background: var(--glass-bg);
            border-radius: var(--border-radius);
            padding: 25px;
            margin-bottom: 25px;
            border: 1px solid var(--glass-border);
        }
        
        .input-group {
            margin-bottom: 22px;
        }
        
        .input-row {
            display: flex;
            gap: 18px;
        }
        
        .input-row .input-group {
            flex: 1;
            margin-bottom: 0;
        }
        
        label {
            display: block;
            margin-bottom: 10px;
            font-weight: 500;
            color: var(--light);
            font-size: 1rem;
        }
        
        input, select {
            width: 100%;
            padding: 15px 18px;
            border: 1px solid var(--glass-border);
            border-radius: 10px;
            font-size: 1rem;
            transition: var(--transition);
            background: rgba(0, 0, 0, 0.2);
            color: var(--light);
        }
        
        .light-mode input, .light-mode select {
            background: rgba(255, 255, 255, 0.8);
            color: var(--light);
        }
        
        input:focus, select:focus {
            border-color: var(--primary);
            outline: none;
            box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
        }
        
        input::placeholder {
            color: var(--gray);
        }
        
        .calculate-btn {
            background: var(--gradient-primary);
            color: white;
            border: none;
            padding: 17px 24px;
            font-size: 1.1rem;
            border-radius: 10px;
            cursor: pointer;
            width: 100%;
            transition: var(--transition);
            font-weight: 600;
            margin-top: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 12px;
            box-shadow: var(--shadow-light);
        }
        
        .calculate-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 10px 20px rgba(67, 97, 238, 0.3);
        }
        
        .unit-selector {
            margin-top: 20px;
            display: flex;
            gap: 10px;
        }
        
        .unit-btn {
            flex: 1;
            padding: 12px;
            background: rgba(0, 0, 0, 0.2);
            border: 1px solid var(--glass-border);
            border-radius: 8px;
            cursor: pointer;
            transition: var(--transition);
            font-weight: 500;
            font-size: 0.9rem;
            color: var(--light);
        }
        
        .light-mode .unit-btn {
            background: rgba(255, 255, 255, 0.8);
        }
        
        .unit-btn.active {
            background: var(--primary);
            border-color: var(--primary);
        }
        
        /* Results */
        .result {
            margin-top: 25px;
            padding: 30px;
            background: var(--glass-bg);
            border-radius: var(--border-radius);
            text-align: center;
            display: none;
            border: 1px solid var(--glass-border);
        }
        
        .result.active {
            display: block;
            animation: fadeIn 0.5s ease;
        }
        
        .result h3 {
            color: var(--light);
            margin-bottom: 18px;
            font-size: 1.6rem;
            font-weight: 600;
        }
        
        .result-value {
            font-size: 2.8rem;
            font-weight: 800;
            color: var(--primary-light);
            margin: 18px 0;
            background: linear-gradient(to right, var(--primary-light), var(--accent));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        
        .results-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 18px;
            margin-top: 25px;
        }
        
        .result-item {
            background: var(--glass-bg);
            padding: 22px;
            border-radius: var(--border-radius-sm);
            border: 1px solid var(--glass-border);
            text-align: left;
        }
        
        .result-label {
            font-size: 0.9rem;
            color: var(--gray);
            margin-bottom: 8px;
            font-weight: 500;
        }
        
        .result-data {
            font-size: 1.35rem;
            font-weight: 700;
            color: var(--light);
        }
        
        /* Footer */
        footer {
            text-align: center;
            color: var(--gray);
            padding: 25px;
            margin-top: 30px;
            font-size: 0.95rem;
            border-top: 1px solid var(--glass-border);
        }
        
        /* Animations */
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }
        
        /* Responsive Design */
        @media (max-width: 1200px) {
            .calculator-content {
                grid-template-columns: 1fr;
            }
            
            .shape-list {
                grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
            }
        }
        
        @media (max-width: 768px) {
            .nav-tabs {
                flex-direction: column;
            }
            
            .nav-tab {
                width: 100%;
                justify-content: center;
            }
            
            .calculator-visual {
                flex-direction: column;
                gap: 25px;
            }
            
            .input-row {
                flex-direction: column;
                gap: 18px;
            }
            
            .shape-diagram {
                font-size: 100px;
            }
            
            .hero h1 {
                font-size: 2.5rem;
            }
            
            .calculator-title {
                font-size: 1.8rem;
            }
            
            .results-grid {
                grid-template-columns: 1fr;
            }
        }
        
        /* Floating Elements */
        .floating-shapes {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
            z-index: -1;
        }
        
        .floating-shape {
            position: absolute;
            opacity: 0.1;
            font-size: 100px;
            animation: float 20s infinite linear;
        }
        
        .floating-shape:nth-child(1) {
            top: 10%;
            left: 5%;
            animation-delay: 0s;
        }
        
        .floating-shape:nth-child(2) {
            top: 20%;
            right: 10%;
            animation-delay: -5s;
        }
        
        .floating-shape:nth-child(3) {
            bottom: 15%;
            left: 15%;
            animation-delay: -10s;
        }
        
        .floating-shape:nth-child(4) {
            bottom: 25%;
            right: 5%;
            animation-delay: -15s;
        }
        
        @keyframes float {
            0% {
                transform: translateY(0) rotate(0deg);
            }
            50% {
                transform: translateY(-20px) rotate(180deg);
            }
            100% {
                transform: translateY(0) rotate(360deg);
            }
        }