:root {
    --primary-color: #4CAF50;
    --secondary-color: #2196F3;
    --accent-color: #FFC107;
    --text-color: #FFFFFF;
    --background-color: #121212;
    --surface-color: #1E1E1E;
}

body {
    font-family: 'Roboto', Arial, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}
.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: var(--surface-color);
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

h1 {
    font-size: 2.5em;
    color: var(--text-color);
    margin-bottom: 20px;
    text-align: center;
}

.checklist {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 15px;
}

.checklist li {
    margin-bottom: 10px;
}

.checklist input[type="checkbox"] {
    display: none;
}

.checklist label {
    display: flex;
    align-items: center;
    padding: 12px 18px;
    background-color: #333333;
    color: var(--text-color);
    border-radius: 10px;
    transition: all 0.3s ease;
    cursor: pointer;
}

.checklist label:hover {
    background-color: #444444;
}

.checklist label:before {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid var(--primary-color);
    border-radius: 3px;
    margin-right: 10px;
    transition: all 0.3s ease;
    flex-shrink: 0;
}

.checklist input[type="checkbox"]:checked + label {
    background-color: var(--primary-color);
}

.checklist input[type="checkbox"]:checked + label:before {
    background-color: var(--text-color);
    border-color: var(--text-color);
}

.checklist input[type="checkbox"]:checked + label:after {
    content: '✓';
    position: absolute;
    left: 24px;
    color: var(--primary-color);
    font-size: 14px;
}

.timer {
    font-size: 48px;
    text-align: center;
    margin: 30px 0;
    font-weight: bold;
}

button {
    display: block;
    width: 100%;
    padding: 15px;
    margin-top: 20px;
    background-color: var(--primary-color);
    color: var(--text-color);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
    font-size: 1.2em;
    text-transform: uppercase;
}

button:hover {
    background-color: #45a049;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

button:active {
    transform: translateY(0);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

button:disabled {
    background-color: #cccccc;
    cursor: not-allowed;
}

#resetButton {
    width: auto;
    padding: 10px 20px;
    font-size: 14px;
    background-color: #f44336;
    margin-top: 20px;
    align-self: flex-end;
}

#resetButton:hover {
    background-color: #d32f2f;
}

.technique {
    margin-top: 30px;
    background-color: #333333;
    border-radius: 10px;
    padding: 20px;
}

.technique img {
    max-width: 100%;
    height: auto;
    border-radius: 10px;
}

.popup {
    display: none;
    position: fixed;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.8);
}

#closePopup {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background: none;
    border: none;
    color: #9CA3AF;
    font-size: 1.5rem;
    cursor: pointer;
}

#closePopup:hover {
    color: #FFFFFF;
}

.progress-bar {
    height: 15px;
    background-color: #333333;
    border-radius: 7.5px;
    margin-bottom: 30px;
    overflow: hidden;
}

.progress {
    height: 100%;
    background-color: var(--primary-color);
    width: 0%;
    transition: width 0.3s ease-in-out;
}

.motivation {
    font-style: italic;
    text-align: center;
    margin: 20px 0;
    color: var(--accent-color);
    font-size: 1.1em;
}

.description {
    margin-top: 20px;
    padding: 15px;
    background-color: #333333;
    border-radius: 10px;
}

.fade-transition {
    transition: opacity 0.3s ease-in-out;
}

@media (min-width: 768px) {
    .mobile-only {
        display: none !important;
    }
}

@media (max-width: 600px) {
    .technique-content {
        flex-direction: column;
    }
    .technique-visual, .technique-info {
        width: 100%;
    }
    .popup-content {
        width: 95%;
        margin: 10% auto;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    .container {
        padding: 20px;
    }
    h1 {
        font-size: 2em;
    }
    .timer {
        font-size: 36px;
    }
    button {
        font-size: 1em;
        padding: 12px;
    }
}

html {
    visibility: visible;
    opacity: 1;
}