:root {
            --primary: #0288d1;
            --primary-dark: #01579b;
            --primary-light: #e0f7fa;
            --secondary: #00bcd4;
            --accent: #ff7043;
            --success: #66bb6a;
            --warning: #ffa726;
            --danger: #ef5350;
            --bg: #f0f9ff;
            --card-bg: rgba(255, 255, 255, 0.85);
            --text: #263238;
            --text-light: #546e7a;
            --border: rgba(2, 136, 209, 0.15);
            --shadow: 0 8px 32px rgba(2, 136, 209, 0.12);
            --shadow-hover: 0 12px 40px rgba(2, 136, 209, 0.2);
            --radius: 20px;
            --transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
        }

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

        @keyframes float {

            0%,
            100% {
                transform: translateY(0px);
            }

            50% {
                transform: translateY(-10px);
            }
        }

        @keyframes pulse-glow {

            0%,
            100% {
                box-shadow: 0 0 20px rgba(2, 136, 209, 0.3);
            }

            50% {
                box-shadow: 0 0 40px rgba(2, 136, 209, 0.6);
            }
        }

        @keyframes wave {
            0% {
                transform: translateX(0) translateZ(0) scaleY(1);
            }

            50% {
                transform: translateX(-25%) translateZ(0) scaleY(0.8);
            }

            100% {
                transform: translateX(-50%) translateZ(0) scaleY(1);
            }
        }

        @keyframes drop {
            0% {
                transform: translateY(-100px) scale(0);
                opacity: 0;
            }

            50% {
                opacity: 1;
            }

            100% {
                transform: translateY(300px) scale(1);
                opacity: 0;
            }
        }

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

            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        @keyframes shimmer {
            0% {
                background-position: -1000px 0;
            }

            100% {
                background-position: 1000px 0;
            }
        }

        @keyframes breathe {

            0%,
            100% {
                transform: scale(1);
            }

            50% {
                transform: scale(1.05);
            }
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: var(--bg);
            color: var(--text);
            line-height: 1.7;
            overflow-x: hidden;
            min-height: 100vh;
        }

        /* Background Animation */

        .bg-animation {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: -1;
            overflow: hidden;
            background: linear-gradient(135deg, #e0f7fa 0%, #b2ebf2 50%, #80deea 100%);
        }

        .bg-animation .drop {
            position: absolute;
            width: 20px;
            height: 20px;
            background: rgba(2, 136, 209, 0.1);
            border-radius: 50% 50% 50% 0;
            transform: rotate(-45deg);
            animation: drop 8s infinite linear;
        }

        .bg-animation .drop:nth-child(1) {
            left: 10%;
            animation-delay: 0s;
            animation-duration: 7s;
        }

        .bg-animation .drop:nth-child(2) {
            left: 30%;
            animation-delay: 2s;
            animation-duration: 9s;
            width: 15px;
            height: 15px;
        }

        .bg-animation .drop:nth-child(3) {
            left: 50%;
            animation-delay: 4s;
            animation-duration: 6s;
            width: 25px;
            height: 25px;
        }

        .bg-animation .drop:nth-child(4) {
            left: 70%;
            animation-delay: 1s;
            animation-duration: 8s;
        }

        .bg-animation .drop:nth-child(5) {
            left: 90%;
            animation-delay: 3s;
            animation-duration: 7s;
            width: 18px;
            height: 18px;
        }

        /* Header */

        header {
            background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
            color: white;
            padding: 1rem 0;
            position: sticky;
            top: 0;
            z-index: 1000;
            box-shadow: 0 4px 20px rgba(2, 136, 209, 0.3);
        }

        .header-content {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 1.5rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            font-size: 1.5rem;
            font-weight: 800;
            text-decoration: none;
            color: white;
        }

        .logo-icon {
            font-size: 2rem;
            animation: float 3s ease-in-out infinite;
            filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.2));
        }

        .nav-menu {
            display: flex;
            gap: 0.5rem;
            list-style: none;
        }

        .nav-menu a {
            color: rgba(255, 255, 255, 0.9);
            text-decoration: none;
            padding: 0.5rem 1rem;
            border-radius: 12px;
            transition: var(--transition);
            font-weight: 600;
            font-size: 0.9rem;
        }

        .nav-menu a:hover,
        .nav-menu a.active {
            background: rgba(255, 255, 255, 0.2);
            color: white;
            transform: translateY(-2px);
        }

        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            color: white;
            font-size: 1.5rem;
            cursor: pointer;
        }

        /* Main Container */

        main {
            max-width: 1200px;
            margin: 0 auto;
            padding: 2rem 1.5rem;
            min-height: calc(100vh - 300px);
        }

        /* Hero Section */

        .hero {
            text-align: center;
            padding: 3rem 1rem;
            animation: fadeInUp 0.8s ease-out;
        }

        .hero h1 {
            font-size: 2.5rem;
            color: var(--primary-dark);
            margin-bottom: 1rem;
            text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.05);
        }

        .hero p {
            font-size: 1.1rem;
            color: var(--text-light);
            max-width: 600px;
            margin: 0 auto 2rem;
        }

        .hero-stats {
            display: flex;
            justify-content: center;
            gap: 2rem;
            margin-top: 2rem;
            flex-wrap: wrap;
        }

        .stat-card {
            background: var(--card-bg);
            backdrop-filter: blur(10px);
            border: 1px solid var(--border);
            border-radius: var(--radius);
            padding: 1.5rem 2rem;
            text-align: center;
            box-shadow: var(--shadow);
            transition: var(--transition);
            min-width: 150px;
        }

        .stat-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-hover);
        }

        .stat-card .number {
            font-size: 2rem;
            font-weight: 800;
            color: var(--primary);
        }

        .stat-card .label {
            font-size: 0.85rem;
            color: var(--text-light);
            margin-top: 0.25rem;
        }

        /* Cards */

        .card {
            background: var(--card-bg);
            backdrop-filter: blur(12px);
            border: 1px solid var(--border);
            border-radius: var(--radius);
            padding: 2rem;
            margin-bottom: 2rem;
            box-shadow: var(--shadow);
            transition: var(--transition);
            animation: fadeInUp 0.6s ease-out;
        }

        .card:hover {
            box-shadow: var(--shadow-hover);
            transform: translateY(-3px);
        }

        .card-title {
            font-size: 1.3rem;
            color: var(--primary-dark);
            margin-bottom: 1.5rem;
            display: flex;
            align-items: center;
            gap: 0.75rem;
        }

        .card-title .icon {
            font-size: 1.5rem;
        }

        /* Form Elements */

        .form-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 1.5rem;
        }

        .form-group {
            display: flex;
            flex-direction: column;
            gap: 0.5rem;
        }

        .form-group label {
            font-weight: 700;
            color: var(--text);
            font-size: 0.95rem;
        }

        .form-group label .required {
            color: var(--danger);
        }

        .form-group input,
        .form-group select,
        .form-group textarea {
            padding: 0.875rem 1rem;
            border: 2px solid var(--border);
            border-radius: 14px;
            font-size: 1rem;
            font-family: inherit;
            background: rgba(255, 255, 255, 0.7);
            transition: var(--transition);
            color: var(--text);
        }

        .form-group input:focus,
        .form-group select:focus,
        .form-group textarea:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 4px rgba(2, 136, 209, 0.1);
            background: white;
        }

        .form-group .hint {
            font-size: 0.8rem;
            color: var(--text-light);
        }

        /* Buttons */

        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
            padding: 0.875rem 2rem;
            border: none;
            border-radius: 14px;
            font-size: 1rem;
            font-weight: 700;
            font-family: inherit;
            cursor: pointer;
            transition: var(--transition);
            text-decoration: none;
        }

        .btn-primary {
            background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
            color: white;
            box-shadow: 0 4px 15px rgba(2, 136, 209, 0.3);
        }

        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(2, 136, 209, 0.4);
        }

        .btn-accent {
            background: linear-gradient(135deg, var(--accent) 0%, #ff8a65 100%);
            color: white;
            box-shadow: 0 4px 15px rgba(255, 112, 67, 0.3);
        }

        .btn-success {
            background: linear-gradient(135deg, var(--success) 0%, #81c784 100%);
            color: white;
        }

        .btn-outline {
            background: transparent;
            border: 2px solid var(--primary);
            color: var(--primary);
        }

        .btn-outline:hover {
            background: var(--primary);
            color: white;
        }

        .btn-lg {
            padding: 1rem 2.5rem;
            font-size: 1.1rem;
        }

        .btn-block {
            width: 100%;
        }

        /* Dashboard */

        .dashboard {
            display: none;
        }

        .dashboard.active {
            display: block;
            animation: fadeInUp 0.5s ease-out;
        }

        .water-progress {
            position: relative;
            width: 200px;
            height: 200px;
            margin: 2rem auto;
        }

        .water-progress svg {
            transform: rotate(-90deg);
        }

        .water-progress .progress-bg {
            fill: none;
            stroke: rgba(2, 136, 209, 0.1);
            stroke-width: 12;
        }

        .water-progress .progress-bar {
            fill: none;
            stroke: url(#waterGradient);
            stroke-width: 12;
            stroke-linecap: round;
            stroke-dasharray: 565;
            stroke-dashoffset: 565;
            transition: stroke-dashoffset 1s ease-out;
        }

        .water-progress .progress-text {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            text-align: center;
        }

        .water-progress .progress-text .percent {
            font-size: 2.5rem;
            font-weight: 800;
            color: var(--primary);
        }

        .water-progress .progress-text .label {
            font-size: 0.85rem;
            color: var(--text-light);
        }

        .water-bottle {
            width: 120px;
            height: 200px;
            margin: 0 auto;
            position: relative;
            border: 4px solid var(--primary);
            border-radius: 20px 20px 40px 40px;
            overflow: hidden;
            background: rgba(255, 255, 255, 0.5);
        }

        .water-bottle .water-fill {
            position: absolute;
            bottom: 0;
            left: 0;
            right: 0;
            background: linear-gradient(to top, var(--primary), var(--secondary));
            transition: height 0.8s ease-out;
            border-radius: 0 0 36px 36px;
        }

        .water-bottle .water-fill::before {
            content: '';
            position: absolute;
            top: -10px;
            left: -50%;
            right: -50%;
            height: 20px;
            background: rgba(255, 255, 255, 0.3);
            border-radius: 50%;
            animation: wave 3s infinite linear;
        }

        .water-bottle .bottle-label {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-weight: 800;
            color: var(--primary-dark);
            font-size: 1.2rem;
            z-index: 2;
        }

        /* Quick Actions */

        .quick-actions {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
            gap: 1rem;
            margin: 2rem 0;
        }

        .action-btn {
            background: white;
            border: 2px solid var(--border);
            border-radius: 16px;
            padding: 1.5rem 1rem;
            text-align: center;
            cursor: pointer;
            transition: var(--transition);
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.5rem;
        }

        .action-btn:hover {
            border-color: var(--primary);
            transform: translateY(-3px);
            box-shadow: var(--shadow);
        }

        .action-btn .icon {
            font-size: 2rem;
        }

        .action-btn .text {
            font-weight: 700;
            font-size: 0.9rem;
            color: var(--text);
        }

        .action-btn .sub {
            font-size: 0.75rem;
            color: var(--text-light);
        }

        /* Timer Display */

        .timer-display {
            background: linear-gradient(135deg, var(--primary-light) 0%, white 100%);
            border-radius: var(--radius);
            padding: 2rem;
            text-align: center;
            margin: 1.5rem 0;
            border: 2px solid var(--border);
        }

        .timer-display .next-drink {
            font-size: 1.1rem;
            color: var(--text-light);
            margin-bottom: 0.5rem;
        }

        .timer-display .countdown {
            font-size: 3rem;
            font-weight: 800;
            color: var(--primary);
            font-family: 'Courier New', monospace;
            letter-spacing: 2px;
        }

        .timer-display .status {
            margin-top: 1rem;
            padding: 0.5rem 1rem;
            border-radius: 20px;
            display: inline-block;
            font-weight: 700;
            font-size: 0.9rem;
        }

        .status.normal {
            background: #e8f5e9;
            color: #2e7d32;
        }

        .status.warning {
            background: #fff3e0;
            color: #ef6c00;
        }

        .status.danger {
            background: #ffebee;
            color: #c62828;
        }

        /* Info Grid */

        .info-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 1.5rem;
            margin: 2rem 0;
        }

        .info-card {
            background: white;
            border-radius: var(--radius);
            padding: 1.5rem;
            border: 1px solid var(--border);
            transition: var(--transition);
            position: relative;
            overflow: hidden;
        }

        .info-card::before {
            content: '';
            position: absolute;
            top: 0;
            right: 0;
            width: 4px;
            height: 100%;
            background: linear-gradient(to bottom, var(--primary), var(--secondary));
        }

        .info-card:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow);
        }

        .info-card h3 {
            color: var(--primary-dark);
            margin-bottom: 0.75rem;
            font-size: 1.1rem;
        }

        .info-card p,
        .info-card li {
            color: var(--text-light);
            font-size: 0.9rem;
            line-height: 1.8;
        }

        .info-card ul {
            padding-right: 1.2rem;
        }

        .info-card li {
            margin-bottom: 0.5rem;
        }

        /* References Section */

        .references {
            background: #f5f5f5;
            border-radius: var(--radius);
            padding: 1.5rem;
            margin-top: 1.5rem;
        }

        .references h4 {
            color: var(--primary-dark);
            margin-bottom: 1rem;
        }

        .references ol {
            padding-right: 1.2rem;
        }

        .references li {
            margin-bottom: 0.5rem;
            font-size: 0.85rem;
            color: var(--text-light);
            line-height: 1.7;
        }

        .references a {
            color: var(--primary);
            text-decoration: none;
        }

        .references a:hover {
            text-decoration: underline;
        }

        /* Footer */

        footer {
            background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 100%);
            color: white;
            padding: 3rem 0 1.5rem;
            margin-top: 4rem;
        }

        .footer-content {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 1.5rem;
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 2rem;
        }

        .footer-section h4 {
            font-size: 1.1rem;
            margin-bottom: 1rem;
            color: #b3e5fc;
        }

        .footer-section ul {
            list-style: none;
        }

        .footer-section li {
            margin-bottom: 0.5rem;
        }

        .footer-section a {
            color: rgba(255, 255, 255, 0.8);
            text-decoration: none;
            transition: var(--transition);
            font-size: 0.9rem;
        }

        .footer-section a:hover {
            color: white;
            padding-right: 5px;
        }

        .footer-bottom {
            text-align: center;
            padding-top: 2rem;
            margin-top: 2rem;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            color: rgba(255, 255, 255, 0.6);
            font-size: 0.85rem;
        }

        /* Modal */

        .modal-overlay {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.5);
            backdrop-filter: blur(5px);
            z-index: 2000;
            display: none;
            align-items: center;
            justify-content: center;
            padding: 1rem;
        }

        .modal-overlay.active {
            display: flex;
            animation: fadeInUp 0.3s ease-out;
        }

        .modal {
            background: white;
            border-radius: var(--radius);
            padding: 2rem;
            max-width: 500px;
            width: 100%;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
            text-align: center;
            position: relative;
        }

        .modal .modal-icon {
            font-size: 4rem;
            margin-bottom: 1rem;
            animation: breathe 2s ease-in-out infinite;
        }

        .modal h2 {
            color: var(--primary-dark);
            margin-bottom: 1rem;
        }

        .modal p {
            color: var(--text-light);
            margin-bottom: 1.5rem;
        }

        .modal-close {
            position: absolute;
            top: 1rem;
            left: 1rem;
            background: none;
            border: none;
            font-size: 1.5rem;
            cursor: pointer;
            color: var(--text-light);
        }

        /* Notification Toast */

        .toast {
            position: fixed;
            bottom: 2rem;
            left: 50%;
            transform: translateX(-50%) translateY(100px);
            background: var(--primary-dark);
            color: white;
            padding: 1rem 2rem;
            border-radius: 50px;
            box-shadow: 0 8px 30px rgba(0, 0, 0, 0.2);
            z-index: 3000;
            opacity: 0;
            transition: all 0.4s ease;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        .toast.show {
            transform: translateX(-50%) translateY(0);
            opacity: 1;
        }

        /* Responsive */

        @media (max-width: 768px) {
            .header-content {
                flex-wrap: wrap;
            }

            .nav-menu {
                display: none;
                width: 100%;
                flex-direction: column;
                margin-top: 1rem;
                background: rgba(0, 0, 0, 0.1);
                border-radius: 12px;
                padding: 0.5rem;
            }

            .nav-menu.active {
                display: flex;
            }

            .mobile-menu-btn {
                display: block;
            }

            .hero h1 {
                font-size: 1.8rem;
            }

            .footer-content {
                grid-template-columns: 1fr;
                text-align: center;
            }

            .water-progress {
                width: 160px;
                height: 160px;
            }

            .timer-display .countdown {
                font-size: 2rem;
            }
        }

        /* Tips Page */

        .tip-card {
            background: white;
            border-radius: var(--radius);
            padding: 1.5rem;
            margin-bottom: 1rem;
            border-right: 4px solid var(--primary);
            box-shadow: var(--shadow);
            transition: var(--transition);
        }

        .tip-card:hover {
            transform: translateX(-5px);
        }

        .tip-card .category {
            display: inline-block;
            background: var(--primary-light);
            color: var(--primary-dark);
            padding: 0.25rem 0.75rem;
            border-radius: 20px;
            font-size: 0.8rem;
            font-weight: 700;
            margin-bottom: 0.5rem;
        }

        .tip-card h4 {
            color: var(--text);
            margin-bottom: 0.5rem;
        }

        .tip-card p {
            color: var(--text-light);
            font-size: 0.9rem;
        }

        /* Hidden */

        .hidden {
            display: none !important;
        }

        /* Section Title */

        .section-title {
            text-align: center;
            margin: 3rem 0 2rem;
        }

        .section-title h2 {
            color: var(--primary-dark);
            font-size: 1.8rem;
            margin-bottom: 0.5rem;
        }

        .section-title p {
            color: var(--text-light);
        }