        :root {
            --primary-bg: #1a1a1a;
            --clock-bg: #000000;
            --text-color: #00ff00;
            --control-bg: #2a2a2a;
            --hover-color: #404040;
        }

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

        body {
            font-family: 'Roboto Mono', monospace;
            background: linear-gradient(135deg, #1a1a1a, #4a4a4a);
            color: #fff;
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            transition: background 0.3s ease;
        }

        .container {
            background: var(--primary-bg);
            padding: 2rem;
            border-radius: 20px;
            box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
            max-width: 800px;
            width: 90%;
        }

        .clock-display {
            background: var(--clock-bg);
            padding: 2rem;
            border-radius: 10px;
            text-align: center;
            margin-bottom: 2rem;
            position: relative;
            overflow: hidden;
        }

        .time {
            font-family: 'Orbitron', sans-serif;
            font-size: 4rem;
            color: var(--text-color);
            text-shadow: 0 0 10px var(--text-color);
            margin-bottom: 1rem;
            transition: color 0.3s ease;
        }

        .date {
            font-size: 1.5rem;
            color: #888;
            margin-bottom: 1rem;
        }

        .controls {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 1rem;
            margin-bottom: 2rem;
        }

        .control-group {
            background: var(--control-bg);
            padding: 1rem;
            border-radius: 10px;
        }

        .control-group h3 {
            margin-bottom: 1rem;
            font-size: 1.2rem;
            color: #fff;
        }

        button {
            background: var(--text-color);
            color: #000;
            border: none;
            padding: 0.5rem 1rem;
            border-radius: 5px;
            cursor: pointer;
            transition: all 0.3s ease;
            margin: 0.25rem;
        }

        button:hover {
            background: var(--hover-color);
            color: var(--text-color);
        }

        select, input {
            background: #333;
            color: #fff;
            border: 1px solid #555;
            padding: 0.5rem;
            border-radius: 5px;
            margin: 0.25rem;
            width: calc(100% - 0.5rem);
        }

        .alarm-list {
            margin-top: 1rem;
            max-height: 200px;
            overflow-y: auto;
        }

        .alarm-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 0.5rem;
            background: #333;
            margin: 0.5rem 0;
            border-radius: 5px;
        }

        .fullscreen {
            position: absolute;
            top: 1rem;
            right: 1rem;
            font-size: 1.5rem;
            cursor: pointer;
        }

        @media (max-width: 768px) {
            .container {
                padding: 1rem;
            }

            .time {
                font-size: 3rem;
            }

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

        .dark-mode {
            --primary-bg: #ffffff;
            --clock-bg: #f0f0f0;
            --text-color: #00aa00;
            --control-bg: #e0e0e0;
            --hover-color: #d0d0d0;
        }

        .timezone-select {
            width: 100%;
            margin-bottom: 1rem;
        }

        .stopwatch {
            font-size: 2rem;
            margin: 1rem 0;
        }

        .timer {
            font-size: 2rem;
            margin: 1rem 0;
        }
