:root {
    --bg-color: #f4f7f9;
    --text-color: #333;
    --card-bg: #fff;
    --border-color: #ddd;
    --primary: #007bff;
    --primary-hover: #0056b3;
    --low: #28a745;
    --medium: #ffc107;
    --high: #dc3545;
    --shadow: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --bg-color: #1c1f26;
    --text-color: #e2e6eb;
    --card-bg: #2a2f38;
    --border-color: #444;
    --primary: #0d6efd;
    --primary-hover: #0a58ca;
    --low: #20c997;
    --medium: #ffc107;
    --high: #ff4d4f;
    --shadow: rgba(255, 255, 255, 0.05);
}


/* GENERAL STYLING */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    margin: 0;
    padding: 20px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 30px;
    position: relative;
}

header h1 {
    color: var(--text-color);
    font-size: 1.8rem;
}

/* Dark Mode Toggle Button */
.theme-toggle {
    position: absolute;
    top: 10px;
    right: 15px;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: 5px;
    padding: 6px 12px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background 0.3s;
}
.theme-toggle:hover {
    background: var(--primary-hover);
}

/* Main Content */
main {
    max-width: 800px;
    margin: 0 auto;
    background: var(--card-bg);
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 4px 10px var(--shadow);
    transition: background-color 0.3s ease;
}

/* Reminder Section */
.reminders {
    margin-bottom: 20px;
}
.reminder-item {
    background-color: #fff3cd;
    color: #856404;
    padding: 10px 15px;
    border-radius: 5px;
    border: 1px solid #ffeeba;
}

/* Task Form */
#task-form {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 10px;
    margin-bottom: 30px;
}

#task-form input,
#task-form select,
#task-form button {
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 16px;
    background: var(--card-bg);
    color: var(--text-color);
}

#task-form button {
    background-color: var(--primary);
    color: white;
    border: none;
    cursor: pointer;
    transition: background-color 0.2s;
}
#task-form button:hover {
    background-color: var(--primary-hover);
}

/* Editing Inputs */
.task-item input,
.task-item select {
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 14px;
    background: var(--card-bg);
    color: var(--text-color);
}
.task-item .save-btn {
    background-color: var(--primary);
    color: white;
    padding: 8px 12px;
}

/* Task Controls */
.task-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    gap: 20px;
    flex-wrap: wrap;
}

/* Progress Bar */
.progress-container {
    flex-grow: 1;
    min-width: 200px;
}
.progress-bar-background {
    width: 100%;
    background-color: var(--border-color);
    border-radius: 5px;
    height: 20px;
}
.progress-bar-foreground {
    height: 100%;
    width: 0%;
    background-color: var(--low);
    border-radius: 5px;
    transition: width 0.4s ease-in-out;
}
#progress-text {
    font-weight: bold;
    color: var(--text-color);
}

/* Filters */
.filters {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}
.filters .filter-btn {
    padding: 8px 16px;
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    cursor: pointer;
    border-radius: 5px;
    margin: 5px;
    color: var(--text-color);
}
.filters .filter-btn.active {
    background-color: var(--primary);
    color: white;
    border-color: var(--primary);
}

/* Task Items */
.task-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    border-left: 5px solid #ccc;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.2s;
    flex-wrap: wrap;
    gap: 10px;
}

.task-item.priority-low { border-left-color: var(--low); }
.task-item.priority-medium { border-left-color: var(--medium); }
.task-item.priority-high { border-left-color: var(--high); }

.task-item.completed {
    background-color: rgba(200, 200, 200, 0.1);
}
.task-item.completed .task-details {
    text-decoration: line-through;
    color: #999;
}

.task-details {
    flex-grow: 1;
    margin-right: 15px;
    min-width: 200px;
}
.task-details .priority-text {
    font-size: 0.8em;
    font-weight: bold;
    text-transform: uppercase;
    padding: 2px 6px;
    border-radius: 4px;
    color: white;
}
.priority-low .priority-text { background-color: var(--low); }
.priority-medium .priority-text { background-color: var(--medium); }
.priority-high .priority-text { background-color: var(--high); }

.task-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}
.task-actions button {
    border: none;
    border-radius: 5px;
    cursor: pointer;
    padding: 8px 12px;
    color: white;
}
.complete-btn { background-color: var(--low); }
.edit-btn { background-color: #17a2b8; }
.delete-btn { background-color: var(--high); }

/* Accessibility and touch optimization */
input, select, button {
    touch-action: manipulation;
}
button {
    min-height: 44px;
}

/* =============================== */
/* 📱 Responsive Design Section */
/* =============================== */

@media (max-width: 768px) {
    main {
        padding: 15px;
    }
    #task-form {
        grid-template-columns: 1fr 1fr;
    }
    #task-form input,
    #task-form select,
    #task-form button {
        font-size: 14px;
        padding: 10px;
    }
    header h1 {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    main {
        padding: 10px;
        box-shadow: none;
    }
    #task-form {
        grid-template-columns: 1fr;
    }
    #task-form button {
        width: 100%;
    }
    .task-item {
        flex-direction: column;
        align-items: flex-start;
    }
    .task-actions {
        width: 100%;
        justify-content: space-between;
    }
    .filters {
        flex-direction: column;
        align-items: center;
    }
    header h1 {
        font-size: 1.3rem;
    }
}