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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.container {
    text-align: center;
    padding: 2rem;
    max-width: 400px;
    width: 100%;
}

.timer-display {
    margin-bottom: 3rem;
}

.time {
    font-size: 4rem;
    font-weight: 300;
    letter-spacing: 0.1em;
    margin-bottom: 1.5rem;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.session-info {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.session-indicator {
    display: flex;
    gap: 0.5rem;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transition: all 0.3s ease;
}

.dot.active {
    background: white;
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
}

.session-type {
    font-size: 1.2rem;
    font-weight: 500;
    letter-spacing: 0.2em;
    opacity: 0.9;
}

.controls {
    margin-top: 2rem;
}

.start-btn {
    background: rgba(255, 255, 255, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.3);
    color: white;
    font-size: 1.2rem;
    font-weight: 500;
    letter-spacing: 0.1em;
    padding: 1rem 2.5rem;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.start-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    border-color: rgba(255, 255, 255, 0.5);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.start-btn:active {
    transform: translateY(0);
}

.start-btn.running {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.2);
}

/* Break mode styling */
body.break-mode {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

/* Responsive design */
@media (max-width: 480px) {
    .time {
        font-size: 3rem;
    }
    
    .container {
        padding: 1rem;
    }
    
    .start-btn {
        font-size: 1rem;
        padding: 0.8rem 2rem;
    }
}