:root {
    --bg-color: #f9f5f0;
    --text-color: #333;
    --primary-color: #8b5fbf;
    --secondary-color: #f0e6ff;
    --accent-color: #6a3093;
    --container-bg: #ffffff;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    --task-complete: #e0f7fa;
    --border-color: #e0e0e0;
    --focus-color: #8b5fbf;
    --break-color: #4caf50;
    --long-break-color: #2196f3;
}

[data-theme="dark"] {
    --bg-color: #1a1a2e;
    --text-color: #e6e6e6;
    --primary-color: #8b5fbf;
    --secondary-color: #2a2a3c;
    --accent-color: #9c64ff;
    --container-bg: #242440;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    --task-complete: #2d3748;
    --border-color: #3a3a4a;
    --focus-color: #8b5fbf;
    --break-color: #4caf50;
    --long-break-color: #2196f3;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background-color 0.3s, color 0.3s;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 20px;
    min-height: 100vh;
}

.app-container {
    max-width: 800px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
    position: relative;
    flex-wrap: wrap;
}

.date-time {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.date {
    font-size: 0.9rem;
    opacity: 0.8;
    margin-bottom: 2px;
}

.clock {
    font-family: 'Courier New', monospace;
    font-size: 1.1rem;
    font-weight: bold;
}

.header-controls {
    display: flex;
    gap: 10px;
}

h1, h2 {
    color: var(--primary-color);
    font-weight: 600;
}

.theme-toggle, .settings-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 5px;
    border-radius: 50%;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover, .settings-toggle:hover {
    background-color: var(--secondary-color);
}

.timer-container {
    background-color: var(--container-bg);
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: border-color 0.3s;
}

.timer-container.focus-mode {
    border: 2px solid var(--focus-color);
}

.timer-container.break-mode {
    border: 2px solid var(--break-color);
}

.timer-container.long-break-mode {
    border: 2px solid var(--long-break-color);
}

.timer-display {
    font-size: 5rem;
    font-weight: 700;
    font-family: 'Courier New', monospace;
    margin: 10px 0;
}

.focus-mode .timer-display {
    color: var(--focus-color);
}

.break-mode .timer-display {
    color: var(--break-color);
}

.long-break-mode .timer-display {
    color: var(--long-break-color);
}

.session-info {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 20px;
    font-size: 1.1rem;
}

.timer-controls {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.control-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s, background-color 0.2s;
}

.control-btn:hover {
    background-color: var(--accent-color);
    transform: scale(1.05);
}

.control-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.tasks-container, .stats-container {
    background-color: var(--container-bg);
    border-radius: 15px;
    padding: 20px;
    box-shadow: var(--shadow);
}

.task-input {
    display: flex;
    gap: 10px;
    margin: 15px 0;
}

.task-input input {
    flex: 1;
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-color);
    color: var(--text-color);
}

.task-input button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 0 15px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.task-input button:hover {
    background-color: var(--accent-color);
}

.task-list {
    list-style: none;
    margin: 15px 0;
}

.task-item {
    display: flex;
    align-items: center;
    padding: 12px 15px;
    margin-bottom: 8px;
    background-color: var(--bg-color);
    border-radius: 8px;
    transition: all 0.2s;
}

.task-item:hover {
    transform: translateX(5px);
}

.task-item.completed {
    background-color: var(--task-complete);
    text-decoration: line-through;
    opacity: 0.8;
}

.task-checkbox {
    margin-right: 12px;
    cursor: pointer;
    width: 18px;
    height: 18px;
}

.task-text {
    flex: 1;
}

.task-delete {
    color: #ff6b6b;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    opacity: 0.7;
}

.task-delete:hover {
    opacity: 1;
}

.task-stats {
    text-align: right;
    font-size: 0.9rem;
    color: var(--primary-color);
    margin-top: 10px;
}

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 15px;
    margin-top: 15px;
}

.stat-item {
    background-color: var(--secondary-color);
    padding: 15px;
    border-radius: 10px;
    text-align: center;
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
    display: block;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.8;
}

.settings-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.settings-content {
    background-color: var(--container-bg);
    padding: 25px;
    border-radius: 15px;
    width: 90%;
    max-width: 500px;
    box-shadow: var(--shadow);
}

.setting-group {
    margin-bottom: 15px;
}

.setting-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}

.setting-group input[type="number"] {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-color);
    color: var(--text-color);
}

.setting-group input[type="checkbox"] {
    margin-right: 8px;
}

.settings-buttons {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 20px;
}

.settings-buttons button {
    padding: 8px 16px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
}

#saveSettingsBtn {
    background-color: var(--primary-color);
    color: white;
}

#saveSettingsBtn:hover {
    background-color: var(--accent-color);
}

#cancelSettingsBtn {
    background-color: var(--secondary-color);
}

#cancelSettingsBtn:hover {
    background-color: var(--border-color);
}

@media (max-width: 600px) {
    .timer-display {
        font-size: 3.5rem;
    }
    
    .control-btn {
        width: 45px;
        height: 45px;
    }
    
    .stats {
        grid-template-columns: 1fr;
    }
    
    .header {
        flex-wrap: wrap;
        gap: 10px;
    }
    
    .date-time {
        order: 3;
        width: 100%;
        text-align: center;
        margin-top: 10px;
    }
    
    .date, .clock {
        width: 100%;
        text-align: center;
    }
}