/* Sleep Optimization Design System */
        :root {
            /* Sleep Color Palette */
            --sleep-primary: #4c1d95;
            --sleep-secondary: #7c3aed;
            --sleep-accent: #06b6d4;
            --sleep-deep: #1e1b4b;
            --sleep-light: #f1f5f9;
            --sleep-dream: #8b5cf6;
            
            /* Sleep Stage Colors */
            --light-sleep: #60a5fa;
            --deep-sleep: #3730a3;
            --rem-sleep: #a855f7;
            --awake-color: #fbbf24;
            --recovery-green: #10b981;
            --moonlight: #e0e7ff;
            
            /* Night Mode Colors */
            --night-dark: #0f172a;
            --night-medium: #1e293b;
            --night-light: #334155;
            --starlight: #e2e8f0;
            
            /* Surface Colors */
            --bg-primary: #ffffff;
            --bg-secondary: #f8fafc;
            --bg-tertiary: #f1f5f9;
            --surface-elevated: #ffffff;
            --text-primary: #1f2937;
            --text-secondary: #6b7280;
            --border-color: rgba(76, 29, 149, 0.2);
            
            /* Spacing Scale */
            --space-xs: 0.25rem;
            --space-sm: 0.5rem;
            --space-md: 1rem;
            --space-lg: 1.5rem;
            --space-xl: 2rem;
            --space-2xl: 3rem;
            --space-3xl: 4rem;
            
            /* Shadows */
            --shadow-sm: 0 1px 2px 0 rgba(76, 29, 149, 0.05);
            --shadow-md: 0 4px 6px -1px rgba(76, 29, 149, 0.1);
            --shadow-lg: 0 10px 15px -3px rgba(76, 29, 149, 0.1);
            --shadow-xl: 0 20px 25px -5px rgba(76, 29, 149, 0.1);
            
            /* Border Radius */
            --radius: 0.75rem;
            --radius-sm: 0.5rem;
            --radius-lg: 1rem;
            --radius-xl: 1.5rem;
            
            /* Transitions */
            --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }

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

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
            background: linear-gradient(135deg, var(--night-dark) 0%, var(--sleep-deep) 30%, var(--sleep-primary) 70%, var(--moonlight) 100%);
            color: var(--text-primary);
            line-height: 1.6;
            min-height: 100vh;
        }

        /* Hero Section */
        .hero {
            background: linear-gradient(135deg, var(--night-dark) 0%, var(--sleep-deep) 30%, var(--sleep-primary) 70%, var(--sleep-secondary) 100%);
            color: white;
            padding: var(--space-3xl) var(--space-lg);
            text-align: center;
            position: relative;
            overflow: hidden;
        }

        .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"><g fill="%23ffffff" opacity="0.08"><circle cx="20" cy="20" r="2"/><circle cx="80" cy="30" r="1.5"/><circle cx="50" cy="50" r="1"/><circle cx="30" cy="80" r="2.5"/><circle cx="70" cy="70" r="1.5"/><circle cx="15" cy="60" r="1"/><circle cx="85" cy="15" r="2"/><circle cx="40" cy="25" r="1.5"/><circle cx="90" cy="85" r="1"/><circle cx="10" cy="90" r="2"/></g></svg>') repeat;
            animation: starfield-drift 30s linear infinite;
            pointer-events: none;
        }

        @keyframes starfield-drift {
            0% { transform: translateX(0) translateY(0); }
            100% { transform: translateX(-50px) translateY(-50px); }
        }

        .hero-badge {
            display: inline-flex;
            align-items: center;
            gap: var(--space-sm);
            background: rgba(255, 255, 255, 0.15);
            backdrop-filter: blur(15px);
            color: white;
            padding: var(--space-sm) var(--space-lg);
            border-radius: 2rem;
            font-size: 0.875rem;
            font-weight: 600;
            margin-bottom: var(--space-lg);
            border: 1px solid rgba(255, 255, 255, 0.2);
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
        }

        .hero-title {
            font-size: clamp(2.5rem, 6vw, 4rem);
            font-weight: 800;
            margin-bottom: var(--space-lg);
            line-height: 1.1;
            text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.3);
            background: linear-gradient(135deg, #ffffff, var(--awake-color));
            background-clip: text;
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .hero-subtitle {
            font-size: 1.25rem;
            opacity: 0.95;
            max-width: 700px;
            margin: 0 auto var(--space-xl);
            line-height: 1.6;
        }

        .difficulty-badge {
            display: inline-flex;
            align-items: center;
            gap: var(--space-xs);
            background: var(--recovery-green);
            color: white;
            padding: var(--space-sm) var(--space-lg);
            border-radius: var(--radius);
            font-weight: 600;
            font-size: 0.875rem;
            box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
        }

        /* Main Container */
        .container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 var(--space-lg);
        }

        /* Educational Section */
        .educational-section {
            background: var(--surface-elevated);
            margin: calc(-1 * var(--space-xl)) var(--space-lg) var(--space-2xl);
            border-radius: var(--radius-xl);
            padding: var(--space-2xl);
            box-shadow: var(--shadow-xl);
            border: 1px solid var(--border-color);
            position: relative;
            z-index: 10;
        }

        .section-title {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--sleep-primary);
            margin-bottom: var(--space-lg);
            display: flex;
            align-items: center;
            gap: var(--space-sm);
        }

        .info-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-xl);
        }

        .info-card {
            background: linear-gradient(135deg, var(--sleep-primary) 0%, var(--sleep-secondary) 100%);
            color: white;
            padding: var(--space-xl);
            border-radius: var(--radius-lg);
            text-align: center;
            transform: translateY(0);
            transition: var(--transition);
            position: relative;
            overflow: hidden;
        }

        .info-card::before {
            content: '';
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background: linear-gradient(45deg, transparent, rgba(255, 255, 255, 0.1), transparent);
            transform: rotate(45deg);
            transition: var(--transition);
            opacity: 0;
        }

        .info-card:hover::before {
            opacity: 1;
            animation: moonbeam 1.5s ease-in-out;
        }

        @keyframes moonbeam {
            0% { transform: translateX(-100%) translateY(-100%) rotate(45deg); }
            100% { transform: translateX(100%) translateY(100%) rotate(45deg); }
        }

        .info-card:hover {
            transform: translateY(-6px);
            box-shadow: var(--shadow-xl);
        }

        .info-card-icon {
            font-size: 2.5rem;
            margin-bottom: var(--space-md);
            filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.2));
        }

        .info-card-title {
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: var(--space-sm);
        }

        .info-card-text {
            font-size: 0.9rem;
            opacity: 0.9;
            line-height: 1.6;
        }

        /* Sleep Cycle Visualization */
        .cycle-visualization {
            background: linear-gradient(145deg, var(--night-dark), var(--night-medium));
            border-radius: var(--radius-xl);
            padding: var(--space-2xl);
            margin: var(--space-xl) 0;
            color: white;
            position: relative;
            overflow: hidden;
        }

        .cycle-visualization::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: radial-gradient(circle at 30% 40%, rgba(168, 85, 247, 0.1) 0%, transparent 50%);
            pointer-events: none;
        }

        .cycle-chart {
            display: grid;
            grid-template-columns: repeat(5, 1fr);
            gap: var(--space-md);
            margin: var(--space-lg) 0;
            position: relative;
            z-index: 1;
        }

        .cycle-block {
            background: rgba(255, 255, 255, 0.1);
            border-radius: var(--radius);
            padding: var(--space-md);
            text-align: center;
            border: 1px solid rgba(255, 255, 255, 0.2);
            transition: var(--transition);
            cursor: pointer;
        }

        .cycle-block:hover {
            transform: translateY(-2px);
            background: rgba(255, 255, 255, 0.15);
        }

        .cycle-number {
            font-size: 1.5rem;
            font-weight: 700;
            margin-bottom: var(--space-xs);
        }

        .cycle-stages {
            display: flex;
            height: 40px;
            border-radius: var(--radius-sm);
            overflow: hidden;
            margin: var(--space-sm) 0;
        }

        .stage-light { background: var(--light-sleep); flex: 2; }
        .stage-deep { background: var(--deep-sleep); flex: 1; }
        .stage-rem { background: var(--rem-sleep); flex: 1; }

        .cycle-time {
            font-size: 0.75rem;
            opacity: 0.8;
        }

        /* Sleep Stage Legend */
        .sleep-legend {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: var(--space-md);
            margin-top: var(--space-lg);
            position: relative;
            z-index: 1;
        }

        .legend-item {
            display: flex;
            align-items: center;
            gap: var(--space-sm);
            font-size: 0.875rem;
        }

        .legend-color {
            width: 16px;
            height: 16px;
            border-radius: 4px;
        }

        /* Calculator Layout */
        .calculator-layout {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: var(--space-2xl);
            margin-bottom: var(--space-3xl);
        }

        .calculator-panel {
            background: var(--surface-elevated);
            border-radius: var(--radius-xl);
            padding: var(--space-2xl);
            box-shadow: var(--shadow-lg);
            border: 1px solid var(--border-color);
            backdrop-filter: blur(10px);
        }

        .panel-title {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--sleep-primary);
            margin-bottom: var(--space-xl);
            display: flex;
            align-items: center;
            gap: var(--space-sm);
        }

        /* Input Controls */
        .input-group {
            margin-bottom: var(--space-xl);
        }

        .input-label {
            display: block;
            font-size: 1rem;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .input-field {
            width: 100%;
            padding: var(--space-lg);
            border: 2px solid var(--border-color);
            border-radius: var(--radius);
            font-size: 1rem;
            transition: var(--transition);
            font-family: inherit;
            background: var(--bg-primary);
        }

        .input-field:focus {
            outline: none;
            border-color: var(--sleep-primary);
            box-shadow: 0 0 0 3px rgba(76, 29, 149, 0.1);
            background: var(--bg-secondary);
        }

        /* Mode Toggle */
        .mode-toggle {
            display: flex;
            background: var(--bg-secondary);
            border-radius: var(--radius);
            padding: 4px;
            margin-bottom: var(--space-xl);
            border: 1px solid var(--border-color);
            box-shadow: var(--shadow-sm);
        }

        .mode-option {
            flex: 1;
            padding: var(--space-md);
            border: none;
            border-radius: calc(var(--radius) - 4px);
            background: transparent;
            cursor: pointer;
            transition: var(--transition);
            font-weight: 600;
            color: var(--text-secondary);
            position: relative;
            overflow: hidden;
        }

        .mode-option::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
            transition: var(--transition);
        }

        .mode-option:hover::before {
            left: 100%;
        }

        .mode-option.active {
            background: linear-gradient(135deg, var(--sleep-primary), var(--sleep-secondary));
            color: white;
            box-shadow: var(--shadow-md);
            transform: translateY(-1px);
        }

        .mode-option:hover:not(.active) {
            background: rgba(76, 29, 149, 0.1);
            color: var(--sleep-primary);
        }

        /* Time Input Enhancement */
        .time-input-group {
            position: relative;
        }

        .time-input {
            font-size: 2rem;
            font-weight: 600;
            text-align: center;
            color: var(--sleep-primary);
            padding: var(--space-lg);
            border: 3px solid var(--sleep-accent);
            border-radius: var(--radius-lg);
            background: linear-gradient(145deg, var(--bg-primary), var(--moonlight));
        }

        .time-input:focus {
            border-color: var(--sleep-primary);
            box-shadow: 0 0 0 4px rgba(76, 29, 149, 0.1);
        }

        /* Sleep Duration Slider */
        .duration-slider {
            margin: var(--space-lg) 0;
        }

        .range-input {
            -webkit-appearance: none;
            width: 100%;
            height: 8px;
            border-radius: 4px;
            background: linear-gradient(to right, var(--light-sleep) 0%, var(--deep-sleep) 50%, var(--rem-sleep) 100%);
            outline: none;
            margin: var(--space-md) 0;
        }

        .range-input::-webkit-slider-thumb {
            -webkit-appearance: none;
            appearance: none;
            width: 24px;
            height: 24px;
            border-radius: 50%;
            background: var(--sleep-primary);
            cursor: pointer;
            box-shadow: 0 4px 8px rgba(76, 29, 149, 0.3);
            transition: var(--transition);
        }

        .range-input::-webkit-slider-thumb:hover {
            transform: scale(1.2);
            box-shadow: 0 6px 12px rgba(76, 29, 149, 0.4);
        }

        .range-input::-moz-range-thumb {
            width: 24px;
            height: 24px;
            border-radius: 50%;
            background: var(--sleep-primary);
            cursor: pointer;
            border: none;
            box-shadow: 0 4px 8px rgba(76, 29, 149, 0.3);
        }

        .range-display {
            display: flex;
            justify-content: space-between;
            font-size: 0.875rem;
            color: var(--text-secondary);
            margin-top: var(--space-sm);
        }

        .range-value {
            font-weight: 600;
            color: var(--sleep-primary);
            font-size: 1.125rem;
        }

        /* Action Buttons */
        .action-buttons {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
            gap: var(--space-md);
            margin-top: var(--space-lg);
        }

        .btn {
            padding: var(--space-md) var(--space-lg);
            border: none;
            border-radius: var(--radius);
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            display: flex;
            align-items: center;
            justify-content: center;
            gap: var(--space-sm);
            font-size: 0.875rem;
            position: relative;
            overflow: hidden;
        }

        .btn::before {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 0;
            height: 0;
            background: rgba(255, 255, 255, 0.3);
            border-radius: 50%;
            transition: all 0.5s ease;
            transform: translate(-50%, -50%);
        }

        .btn:hover::before {
            width: 300px;
            height: 300px;
        }

        .btn-primary {
            background: linear-gradient(135deg, var(--sleep-primary), var(--sleep-secondary));
            color: white;
            box-shadow: var(--shadow-md);
        }

        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-lg);
        }

        .btn-secondary {
            background: var(--bg-secondary);
            color: var(--text-primary);
            border: 1px solid var(--border-color);
        }

        .btn-secondary:hover {
            background: rgba(76, 29, 149, 0.1);
            border-color: var(--sleep-primary);
        }

        /* Results Display */
        .results-panel {
            background: linear-gradient(145deg, var(--bg-secondary), var(--moonlight));
            border: 3px solid var(--sleep-primary);
            border-radius: var(--radius-lg);
            padding: var(--space-2xl);
            margin: var(--space-lg) 0;
            position: relative;
            overflow: hidden;
            opacity: 0;
            transform: translateY(20px);
            transition: all 0.6s ease;
        }

        .results-panel.show {
            opacity: 1;
            transform: translateY(0);
        }

        .results-panel::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: radial-gradient(circle at center, rgba(76, 29, 149, 0.05) 0%, transparent 70%);
            pointer-events: none;
        }

        /* Sleep Time Options */
        .sleep-options {
            display: grid;
            gap: var(--space-md);
            margin: var(--space-xl) 0;
        }

        .sleep-option {
            background: var(--surface-elevated);
            border: 2px solid var(--border-color);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: var(--transition);
            cursor: pointer;
            position: relative;
            overflow: hidden;
        }

        .sleep-option::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 4px;
            height: 100%;
            background: var(--light-sleep);
            transition: var(--transition);
        }

        .sleep-option.recommended {
            border-color: var(--recovery-green);
            background: rgba(16, 185, 129, 0.05);
        }

        .sleep-option.recommended::before {
            background: var(--recovery-green);
            width: 8px;
        }

        .sleep-option.recommended::after {
            content: '⭐ RECOMMENDED';
            position: absolute;
            top: var(--space-sm);
            right: var(--space-sm);
            background: var(--recovery-green);
            color: white;
            padding: var(--space-xs) var(--space-sm);
            border-radius: var(--radius-sm);
            font-size: 0.75rem;
            font-weight: 600;
        }

        .sleep-option:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
            border-color: var(--sleep-primary);
        }

        .sleep-time {
            font-size: 2rem;
            font-weight: 800;
            color: var(--sleep-primary);
            margin-bottom: var(--space-xs);
        }

        .sleep-label {
            font-size: 1rem;
            color: var(--text-secondary);
            margin-bottom: var(--space-sm);
        }

        .sleep-details {
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 0.875rem;
            color: var(--text-secondary);
        }

        .cycles-info {
            display: flex;
            align-items: center;
            gap: var(--space-xs);
        }

        .quality-indicator {
            display: flex;
            align-items: center;
            gap: var(--space-xs);
            padding: var(--space-xs) var(--space-sm);
            background: rgba(76, 29, 149, 0.1);
            border-radius: var(--radius-sm);
            font-weight: 600;
            color: var(--sleep-primary);
        }

        /* Sleep Quality Visualization */
        .quality-chart {
            background: var(--surface-elevated);
            border-radius: var(--radius-lg);
            padding: var(--space-xl);
            margin: var(--space-lg) 0;
            border: 1px solid var(--border-color);
        }

        .quality-bars {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
            gap: var(--space-md);
            margin-top: var(--space-lg);
        }

        .quality-bar {
            text-align: center;
        }

        .quality-meter {
            height: 100px;
            width: 20px;
            background: rgba(76, 29, 149, 0.1);
            border-radius: 10px;
            margin: 0 auto var(--space-sm);
            position: relative;
            overflow: hidden;
        }

        .quality-fill {
            position: absolute;
            bottom: 0;
            width: 100%;
            background: linear-gradient(to top, var(--deep-sleep), var(--rem-sleep));
            border-radius: 10px;
            transition: height 1.5s ease-out;
        }

        .quality-label {
            font-size: 0.75rem;
            font-weight: 600;
            color: var(--text-secondary);
        }

        /* Sleep Tips */
        .sleep-tips {
            background: linear-gradient(135deg, var(--recovery-green), var(--sleep-accent));
            color: white;
            border-radius: var(--radius-lg);
            padding: var(--space-xl);
            margin: var(--space-lg) 0;
            position: relative;
            overflow: hidden;
        }

        .sleep-tips::before {
            content: '';
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background: linear-gradient(45deg, transparent, rgba(255, 255, 255, 0.1), transparent);
            animation: tip-shine 3s linear infinite;
        }

        @keyframes tip-shine {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }

        .tip-title {
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: var(--space-md);
            position: relative;
            z-index: 1;
        }

        .tip-list {
            list-style: none;
            position: relative;
            z-index: 1;
        }

        .tip-item {
            padding: var(--space-sm) 0;
            border-bottom: 1px solid rgba(255, 255, 255, 0.2);
            display: flex;
            align-items: flex-start;
            gap: var(--space-sm);
        }

        .tip-item:last-child {
            border-bottom: none;
        }

        .tip-icon {
            font-size: 1.125rem;
            margin-top: 2px;
        }

        .tip-text {
            font-size: 0.875rem;
            line-height: 1.5;
        }

        .tip-item:last-child {
            border-bottom: none;
        }

        .tip-icon {
            font-size: 1.125rem;
            margin-top: 2px;
        }

        .tip-text {
            font-size: 0.875rem;
            line-height: 1.5;
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .calculator-layout {
                grid-template-columns: 1fr;
                gap: var(--space-xl);
            }

            .info-grid {
                grid-template-columns: 1fr;
            }

            .cycle-chart {
                grid-template-columns: repeat(2, 1fr);
            }

            .sleep-legend {
                grid-template-columns: 1fr;
            }

            .quality-bars {
                grid-template-columns: repeat(3, 1fr);
            }

            .hero {
                padding: var(--space-2xl) var(--space-lg);
            }

            .educational-section {
                margin-left: 0;
                margin-right: 0;
                border-radius: 0;
            }

            .action-buttons {
                grid-template-columns: 1fr;
            }

            .sleep-time {
                font-size: 1.5rem;
            }
        }
        /* Animation Classes */
        .fade-in {
            animation: fadeIn 0.6s ease-out;
        }

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

        .pulse-glow {
            animation: pulse-glow 2s infinite;
        }

        @keyframes pulse-glow {
            0%, 100% { 
                box-shadow: var(--shadow-md);
                transform: scale(1);
            }
            50% { 
                box-shadow: 0 0 20px rgba(76, 29, 149, 0.4);
                transform: scale(1.02);
            }
        }

        /* Clock Animation */
        .clock-animation {
            position: relative;
            width: 60px;
            height: 60px;
            border: 3px solid var(--sleep-primary);
            border-radius: 50%;
            margin: 0 auto var(--space-md);
        }

        .clock-hand {
            position: absolute;
            background: var(--sleep-primary);
            transform-origin: bottom center;
            border-radius: 2px;
        }

        .hour-hand {
            width: 3px;
            height: 20px;
            top: 10px;
            left: 50%;
            margin-left: -1.5px;
            animation: rotate-hour 43200s linear infinite;
        }

        .minute-hand {
            width: 2px;
            height: 25px;
            top: 5px;
            left: 50%;
            margin-left: -1px;
            animation: rotate-minute 3600s linear infinite;
        }

        @keyframes rotate-hour {
            from { transform: rotate(0deg); }
            to { transform: rotate(360deg); }
        }

        @keyframes rotate-minute {
            from { transform: rotate(0deg); }
            to { transform: rotate(360deg); }
        }