body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: #f2f2f2;
    margin: 0;
    padding: 1rem;
}

.container {
    text-align: center;
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    max-width: 500px;
    width: 100%;
}

/* Configuration Section */
.config-section {
    background: #f8f9fa;
    border-radius: 0.5rem;
    padding: 1.5rem;
    margin-bottom: 2rem;
    border: 1px solid #e9ecef;
}

.config-section h3 {
    margin-top: 0;
    color: #333;
    font-size: 1.2rem;
}

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

.config-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    min-width: 200px;
}

.config-item label {
    font-weight: bold;
    min-width: 70px;
    text-align: right;
    color: #555;
}

.config-item input[type="number"] {
    width: 60px;
    padding: 0.3rem;
    border: 1px solid #ccc;
    border-radius: 0.3rem;
    font-size: 1rem;
    text-align: center;
}

.config-item input[type="number"]:focus {
    outline: none;
    border-color: #ff4b5c;
    box-shadow: 0 0 0 2px rgba(255, 75, 92, 0.2);
}

/* Configuration Buttons */
.config-btn {
    margin: 0.3rem;
    padding: 0.4rem 1rem;
    font-size: 0.9rem;
    border: none;
    border-radius: 0.3rem;
    cursor: pointer;
    background: #28a745;
    color: white;
    transition: background 0.3s;
}

.config-btn:hover {
    background: #218838;
}

.config-btn.secondary {
    background: #6c757d;
}

.config-btn.secondary:hover {
    background: #545b62;
}

/* Timer Display */
#timer {
    font-size: 3rem;
    margin: 1rem 0;
    font-weight: bold;
    color: #333;
}

/* Main Control Buttons */
button {
    margin: 0.5rem;
    padding: 0.5rem 1.5rem;
    font-size: 1rem;
    border: none;
    border-radius: 0.5rem;
    cursor: pointer;
    background: #ff4b5c;
    color: white;
    transition: background 0.3s;
}

button:hover {
    background: #ff1e38;
}

/* Presets Section */
.presets {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid #e9ecef;
}

.presets h4 {
    color: #555;
    margin-bottom: 1rem;
}

.preset-btn {
    background: #17a2b8;
    font-size: 0.9rem;
    padding: 0.4rem 0.8rem;
    margin: 0.2rem;
}

.preset-btn:hover {
    background: #138496;
}

/* Hidden state for config */
.config-section.hidden {
    display: none;
}

/* Responsive Design */
@media (max-width: 480px) {
    .container {
        padding: 1rem;
    }

    #timer {
        font-size: 2.5rem;
    }

    .config-controls {
        gap: 0.8rem;
    }

    .config-item {
        min-width: auto;
        flex-direction: column;
        text-align: center;
    }

    .config-item label {
        min-width: auto;
        text-align: center;
    }

    .presets {
        margin-top: 1.5rem;
    }

    .preset-btn {
        display: block;
        width: 100%;
        margin: 0.3rem 0;
    }
}