* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Poppins', sans-serif;
            background: linear-gradient(135deg, #0891b2 0%, #14b8a6 50%, #06b6d4 100%);
            min-height: 100vh;
            color: var(--dark);
            position: relative;
            overflow-x: hidden;
        }

        body::before {
            content: '';
            position: fixed;
            top: -50%;
            right: -50%;
            width: 200%;
            height: 200%;
            background: 
                radial-gradient(circle at 20% 50%, rgba(255,255,255,0.15) 0%, transparent 50%),
                radial-gradient(circle at 80% 80%, rgba(255,255,255,0.1) 0%, transparent 50%),
                radial-gradient(circle, rgba(255,255,255,0.08) 1px, transparent 1px);
            background-size: 100% 100%, 100% 100%, 40px 40px;
            animation: moveGrid 25s linear infinite;
            z-index: 0;
        }

        @keyframes moveGrid {
            0% { transform: translate(0, 0); }
            100% { transform: translate(50px, 50px); }
        }

        .seo-block {
            background: transparent;
            margin-top: 3rem;
        }

        .container {
            max-width: 1400px;
            margin: 0 auto;
            position: relative;
            z-index: 1;
        }

        @keyframes fadeInDown {
            from {
                opacity: 0;
                transform: translateY(-30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .subtitle {
            font-size: 1.2rem;
            color: rgba(255,255,255,0.9);
            font-weight: 300;
        }

        .main-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 30px;
            margin-bottom: 30px;
        }

        .card {
            background: var(--white);
            border-radius: 24px;
            padding: 35px;
            box-shadow: 0 20px 60px rgba(0,0,0,0.2);
            animation: fadeInUp 0.8s ease;
            animation-fill-mode: both;
            position: relative;
            overflow: hidden;
        }

        .card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 4px;
            background: linear-gradient(90deg, var(--primary), var(--secondary), var(--accent));
        }

        .card:nth-child(2) {
            animation-delay: 0.1s;
        }

        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .card-header {
            display: flex;
            align-items: center;
            gap: 15px;
            margin-bottom: 30px;
            padding-bottom: 20px;
            border-bottom: 2px solid var(--bg-pattern);
        }

        .card-icon {
            width: 50px;
            height: 50px;
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            border-radius: 14px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 24px;
            box-shadow: 0 4px 14px rgb(185 185 185 / 40%);
        }

        .card-title {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--dark);
        }

        .form-group {
            margin-bottom: 25px;
        }

        label {
            display: block;
            margin-bottom: 10px;
            font-weight: 600;
            color: var(--dark);
            font-size: 0.95rem;
        }

        input[type="number"],
        select {
            width: 100%;
            padding: 15px 20px;
            border: 2px solid var(--gray-light);
            border-radius: 12px;
            font-size: 1rem;
            font-family: 'Space Mono', monospace;
            transition: all 0.3s ease;
            background: var(--white);
        }

        input[type="number"]:focus,
        select:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 4px rgba(6, 182, 212, 0.15);
        }

        .gst-rate-selector {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
            gap: 10px;
            margin-top: 10px;
        }

        .gst-rate-btn {
            padding: 12px;
            border: 2px solid var(--gray-light);
            background: var(--white);
            border-radius: 10px;
            cursor: pointer;
            font-weight: 600;
            font-family: 'Space Mono', monospace;
            transition: all 0.3s ease;
            font-size: 0.95rem;
        }

        .gst-rate-btn:hover {
            border-color: var(--primary);
            background: rgba(6, 182, 212, 0.08);
        }

        .gst-rate-btn.active {
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            color: var(--white);
            border-color: transparent;
            box-shadow: 0 4px 14px rgb(185 185 185 / 40%);
        }

        .calculation-type {
            display: flex;
            gap: 15px;
            margin-bottom: 25px;
        }

        .type-btn {
            flex: 1;
            padding: 15px;
            border: 2px solid var(--gray-light);
            background: var(--white);
            border-radius: 12px;
            cursor: pointer;
            font-weight: 600;
            transition: all 0.3s ease;
            font-size: 1rem;
        }

        .type-btn:hover {
            border-color: var(--primary);
            background: rgba(6, 182, 212, 0.08);
        }

        .type-btn.active {
            color: var(--white);
            border-color: transparent;
            box-shadow: 0 4px 14px rgb(185 185 185 / 40%);
        }

        .result-box {
            border-radius: 16px;
            padding: 30px;
            margin-top: 25px;
            color: var(--white);
            border: 1px #ddd solid;
        }

        .result-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px 0;
            border-bottom: 1px solid rgba(255,255,255,0.2);
        }

        .result-item:last-child {
            border-bottom: none;
            font-size: 1.3rem;
            font-weight: 700;
            padding-top: 20px;
            margin-top: 10px;
            border-top: 2px solid rgba(255,255,255,0.3);
        }

        .result-label {
            font-weight: 400;
            opacity: 0.9;
        }

        .result-value {
            font-family: 'Space Mono', monospace;
            font-weight: 700;
            font-size: 1.2rem;
        }

        .button-group {
            display: flex;
            gap: 15px;
            margin-top: 25px;
        }

        .btn {
            flex: 1;
            padding: 16px 24px;
            border: none;
            border-radius: 12px;
            font-weight: 700;
            font-size: 1rem;
            cursor: pointer;
            transition: all 0.3s ease;
            font-family: 'Poppins', sans-serif;
            text-transform: uppercase;
            letter-spacing: 0.5px;
        }

        .btn-primary {
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            color: var(--white);
            box-shadow: 0 4px 14px rgb(185 185 185 / 40%);
        }

        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 14px rgb(185 185 185 / 40%);
        }

        .btn-secondary {
            background: var(--white);
            color: var(--dark);
            border: 2px solid var(--gray-light);
        }

        .btn-secondary:hover {
            border-color: var(--primary);
            color: var(--primary);
        }

        .calculator-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 20px;
            animation: fadeInUp 0.8s ease 0.2s;
            animation-fill-mode: both;
        }

        .calc-card {
            background: var(--white);
            border-radius: 20px;
            padding: 30px;
            box-shadow: 0 10px 40px rgba(0,0,0,0.15);
            text-align: center;
            transition: all 0.3s ease;
            cursor: pointer;
            border: 3px solid transparent;
        }

        .calc-card-icon {
            font-size: 3rem;
            margin-bottom: 15px;
        }

        .calc-card-title {
            font-size: 1.2rem;
            font-weight: 700;
            color: var(--dark);
            margin-bottom: 8px;
        }

        .calc-card-desc {
            font-size: 0.9rem;
            color: var(--gray);
        }

        .info-section {
            background: var(--white);
            border-radius: 24px;
            padding: 40px;
            margin-top: 30px;
            box-shadow: 0 20px 60px rgba(0,0,0,0.2);
            animation: fadeInUp 0.8s ease 0.3s;
            animation-fill-mode: both;
        }

        .info-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 25px;
            margin-top: 25px;
        }

        .info-card {
            background: var(--bg-pattern);
            padding: 25px;
            border-radius: 16px;
            border-left: 4px solid var(--primary);
        }

        .info-card h3 {
            color: var(--primary);
            margin-bottom: 10px;
            font-size: 1.1rem;
        }

        .info-card p {
            color: var(--gray);
            line-height: 1.6;
            font-size: 0.95rem;
        }

        footer {
            text-align: center;
            margin-top: 50px;
            color: rgba(255,255,255,0.8);
            padding: 20px;
        }

        @media (max-width: 1024px) {
            .main-grid {
                grid-template-columns: 1fr;
            }
            .calculator-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        @media (max-width: 768px) {
            h1 {
                font-size: 2.5rem;
            }
            .calculator-grid {
                grid-template-columns: 1fr;
            }
            .card {
                padding: 25px;
            }
        }

        .modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.7);
            z-index: 1000;
            justify-content: center;
            align-items: center;
            padding: 20px;
        }

        .modal.active {
            display: flex;
        }

        .modal-content {
            background: var(--white);
            border-radius: 24px;
            padding: 40px;
            max-width: 600px;
            width: 100%;
            max-height: 90vh;
            overflow-y: auto;
            animation: scaleIn 0.3s ease;
        }

        @keyframes scaleIn {
            from {
                transform: scale(0.9);
                opacity: 0;
            }
            to {
                transform: scale(1);
                opacity: 1;
            }
        }

        .modal-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 25px;
            padding-bottom: 20px;
            border-bottom: 2px solid var(--bg-pattern);
        }

        .close-modal {
            background: none;
            border: none;
            font-size: 2rem;
            cursor: pointer;
            color: var(--gray);
            transition: all 0.3s ease;
            width: 40px;
            height: 40px;
            display: flex;
            align-items: center;
            justify-content: center;
            border-radius: 10px;
        }

        .close-modal:hover {
            background: var(--bg-pattern);
            color: var(--dark);
        }

        .invoice-item-row {
            position: relative;
        }

        .remove-item-btn {
            background: var(--danger);
            color: var(--white);
            border: none;
            border-radius: 8px;
            width: 40px;
            height: 40px;
            cursor: pointer;
            font-size: 1.2rem;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s ease;
        }

        .remove-item-btn:hover {
            background: #dc2626;
            transform: scale(1.1);
        }

        input[type="text"],
        input[type="date"] {
            width: 100%;
            padding: 15px 20px;
            border: 2px solid var(--gray-light);
            border-radius: 12px;
            font-size: 1rem;
            font-family: 'Poppins', sans-serif;
            transition: all 0.3s ease;
            background: var(--white);
        }

        input[type="text"]:focus,
        input[type="date"]:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 4px rgba(6, 182, 212, 0.15);
        }