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

body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    background-color: #f0f5f9;
    color: #456268;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 1s ease;
}

.container {
    background-color: #ffffff;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    width: 90%;
    max-width: 500px;
    text-align: center;
}

h1 {
    margin-bottom: 2rem;
    color: #456268;
    font-weight: 300;
    letter-spacing: 1px;
}

.breathing-box {
    position: relative;
    width: 200px;
    height: 200px;
    margin: 0 auto 2rem;
    display: flex;
    justify-content: center;
    align-items: center;
}

.visual-cue {
    position: absolute;
    width: 100px;
    height: 100px;
    background-color: rgba(142, 202, 230, 0.3);
    border-radius: 10px;
    transition: all 4s ease;
}

.visual-cue.inhale {
    transform: scale(1.8);
    background-color: rgba(142, 202, 230, 0.5);
}

.visual-cue.hold-after-inhale {
    transform: scale(1.8);
    background-color: rgba(142, 202, 230, 0.7);
}

.visual-cue.exhale {
    transform: scale(1);
    background-color: rgba(142, 202, 230, 0.5);
}

.visual-cue.hold-after-exhale {
    transform: scale(1);
    background-color: rgba(142, 202, 230, 0.3);
}

.instruction {
    position: relative;
    z-index: 10;
    font-size: 1.5rem;
    font-weight: 300;
    color: #456268;
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.8);
    margin-bottom: 0.5rem;
}

.phase-timer {
    position: relative;
    z-index: 10;
    font-size: 2.5rem;
    font-weight: 300;
    color: rgba(69, 98, 104, 0.5);
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.8);
}

.phase-indicator {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.phase-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: #e6eef2;
    transition: all 0.3s ease;
}

.phase-dot.active {
    background-color: #8ecae6;
    transform: scale(1.2);
}

.timer {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: #456268;
    font-weight: 300;
}

.progress {
    margin-bottom: 2rem;
}

.round-indicator {
    margin-bottom: 0.5rem;
    font-size: 1rem;
    color: #456268;
}

.progress-bar {
    height: 8px;
    background-color: #e6eef2;
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    width: 0;
    background-color: #8ecae6;
    border-radius: 4px;
    transition: width 0.5s ease;
}

.controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 50px;
    background-color: #8ecae6;
    color: white;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn:hover {
    background-color: #73b8d9;
    transform: translateY(-2px);
}

.btn:disabled {
    background-color: #c5d5de;
    cursor: not-allowed;
    transform: none;
}

/* Phase-specific body backgrounds */
body.inhale {
    background-color: #e6f3f8;
}

body.hold-after-inhale {
    background-color: #d9edf5;
}

body.exhale {
    background-color: #f0f5f9;
}

body.hold-after-exhale {
    background-color: #e6eef2;
}

.settings-toggle {
    margin-top: 1rem;
    text-align: center;
}

.btn-small {
    padding: 0.5rem;
    border: none;
    border-radius: 50%;
    background-color: #e6eef2;
    color: #456268;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-small:hover {
    background-color: #d9e6ed;
    transform: translateY(-2px);
}

.settings-panel {
    margin-top: 1.5rem;
    padding: 1rem;
    background-color: #f8fbfd;
    border-radius: 10px;
    transition: all 0.3s ease;
}

.settings-panel.hidden {
    display: none;
}

.settings-panel h3 {
    margin-bottom: 1rem;
    font-weight: 300;
    color: #456268;
}

.setting {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.setting label {
    color: #456268;
}

.setting input[type="number"] {
    width: 60px;
    padding: 0.5rem;
    border: 1px solid #e6eef2;
    border-radius: 4px;
    text-align: center;
}

.setting select {
    width: 120px;
    padding: 0.5rem;
    border: 1px solid #e6eef2;
    border-radius: 4px;
    background-color: white;
    color: #456268;
}

.setting.hidden {
    display: none;
}

.keyboard-shortcuts {
    position: fixed;
    bottom: 1rem;
    left: 1rem;
    background-color: rgba(255, 255, 255, 0.8);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-size: 0.8rem;
    color: #456268;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.shortcut {
    margin: 0.3rem 0;
}

.shortcut span {
    display: inline-block;
    padding: 0.1rem 0.4rem;
    background-color: #e6eef2;
    border-radius: 3px;
    margin-right: 0.3rem;
    font-weight: bold;
}

/* Responsive adjustments */
@media (max-width: 600px) {
    .container {
        padding: 1.5rem;
    }
    
    .breathing-box {
        width: 150px;
        height: 150px;
    }
    
    .visual-cue {
        width: 80px;
        height: 80px;
    }
    
    .instruction {
        font-size: 1.2rem;
    }
    
    .phase-timer {
        font-size: 2rem;
    }
    
    .timer {
        font-size: 1.5rem;
    }
    
    .keyboard-shortcuts {
        display: none; /* Hide keyboard shortcuts on mobile */
    }
}