/* --- FONT & BASIC SETUP --- */
:root {
    font-family: 'Poppins', sans-serif;
    --font-light: 300;
    --font-normal: 400;
    --font-bold: 600;
    --transition-speed: 0.3s;
}

/* --- COLOR PALETTES --- */
[data-palette="ocean"] {
    --bg-color: #f0f8ff;
    --surface-color: #ffffff;
    --text-color: #0a2a42;
    --primary-color: #0077b6;
    --accent-color: #00b4d8;
    --border-color: #e0eaf0;
    --shadow-color: rgba(10, 42, 66, 0.1);
    --completed-color: #809eb1;
}

[data-palette="forest"] {
    --bg-color: #f5fdf5;
    --surface-color: #ffffff;
    --text-color: #1e4620;
    --primary-color: #2a6f2b;
    --accent-color: #4caf50;
    --border-color: #e4ede4;
    --shadow-color: rgba(30, 70, 32, 0.1);
    --completed-color: #8a9f8a;
}

[data-palette="purple"] {
    --bg-color: #f8f7ff;
    --surface-color: #ffffff;
    --text-color: #2c134d;
    --primary-color: #6a0dad;
    --accent-color: #9370db;
    --border-color: #e9e4f0;
    --shadow-color: rgba(44, 19, 77, 0.1);
    --completed-color: #958aab;
}

/* --- DARK MODE --- */
[data-theme="dark"] {
    --bg-color: #121212;
    --surface-color: #1e1e1e;
    --text-color: #e0e0e0;
    --border-color: #2c2c2c;
    --shadow-color: rgba(0, 0, 0, 0.2);
    --completed-color: #555;
}

[data-theme="dark"][data-palette="ocean"] {
    --primary-color: #48bfe3;
    --accent-color: #0096c7;
}

[data-theme="dark"][data-palette="forest"] {
    --primary-color: #66bb6a;
    --accent-color: #43a047;
}

[data-theme="dark"][data-palette="purple"] {
    --primary-color: #b39ddb;
    --accent-color: #7e57c2;
}


/* --- GENERAL STYLING --- */
body {
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 1rem;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background-color: var(--surface-color);
    border-radius: 12px;
    box-shadow: 0 4px 15px var(--shadow-color);
    margin-bottom: 2rem;
}

.app-header h1 {
    font-size: 1.5rem;
    font-weight: var(--font-bold);
    color: var(--primary-color);
}

.controls {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.theme-selector select {
    background-color: var(--bg-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.5rem;
    font-family: inherit;
    cursor: pointer;
}

/* --- THEME SWITCH --- */
.theme-switch-wrapper {
    display: flex;
    align-items: center;
}
.theme-switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 28px;
}
.theme-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}
.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: var(--transition-speed);
    border-radius: 28px;
}
.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: var(--transition-speed);
    border-radius: 50%;
}
input:checked + .slider {
    background-color: var(--primary-color);
}
input:checked + .slider:before {
    transform: translateX(22px);
}

/* --- TASK BOARD --- */
.task-board {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.day-column h2 {
    font-size: 1.2rem;
    font-weight: var(--font-bold);
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.time-slot {
    background-color: var(--surface-color);
    border-radius: 12px;
    padding: 1rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 15px var(--shadow-color);
    transition: box-shadow var(--transition-speed);
}

.time-slot:hover {
    box-shadow: 0 6px 20px var(--shadow-color);
}

.time-slot h3 {
    font-size: 1rem;
    font-weight: var(--font-bold);
    margin-top: 0;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent-color);
}

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

.task-item {
    display: flex;
    align-items: center;
    padding: 0.75rem 0.5rem;
    border-bottom: 1px solid var(--border-color);
    transition: opacity var(--transition-speed);
}

.task-item:last-child {
    border-bottom: none;
}

.task-item label {
    flex-grow: 1;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: var(--font-normal);
    transition: color var(--transition-speed), text-decoration var(--transition-speed);
}

.task-item input[type="checkbox"] {
    display: none; /* Hide original checkbox */
}

.task-item .custom-checkbox {
    width: 20px;
    height: 20px;
    border: 2px solid var(--accent-color);
    border-radius: 50%;
    display: inline-block;
    position: relative;
    cursor: pointer;
    flex-shrink: 0;
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.task-item input[type="checkbox"]:checked + .custom-checkbox {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}

.task-item input[type="checkbox"]:checked + .custom-checkbox::after {
    content: '✔';
    font-size: 14px;
    color: var(--surface-color);
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.task-item.completed label {
    text-decoration: line-through;
    color: var(--completed-color);
    opacity: 0.7;
}

.task-item.completed .task-emoji {
    filter: grayscale(80%);
    opacity: 0.7;
}

.delete-task-btn {
    background: transparent;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    font-size: 1.2rem;
    padding: 0 0.5rem;
    opacity: 0.5;
    transition: opacity var(--transition-speed), color var(--transition-speed);
}

.delete-task-btn:hover {
    opacity: 1;
    color: #e74c3c; /* A nice red color for delete */
}

/* --- RESPONSIVENESS --- */
@media (max-width: 768px) {
    .app-header {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
    .controls {
        width: 100%;
        justify-content: space-between;
    }
    .task-board {
        grid-template-columns: 1fr;
    }
}

/* --- ADD TASK BUTTON --- */
.add-task-btn {
    background-color: var(--primary-color);
    color: var(--surface-color);
    border: none;
    border-radius: 50%;
    width: 30px;
    height: 30px;
    font-size: 1.5rem;
    line-height: 30px;
    text-align: center;
    cursor: pointer;
    position: absolute;
    bottom: 10px;
    right: 10px;
    opacity: 0.7;
    transition: opacity var(--transition-speed), transform var(--transition-speed);
}

.add-task-btn:hover {
    opacity: 1;
    transform: scale(1.1);
}

.time-slot {
    position: relative; /* Needed for positioning the add button */
}

/* --- MODAL STYLES --- */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal-content {
    background-color: var(--surface-color);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
    width: 90%;
    max-width: 400px;
}

.modal-content h2 {
    margin-top: 0;
    color: var(--primary-color);
    text-align: center;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: var(--font-bold);
    color: var(--text-color);
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: inherit;
}

.form-group select:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    margin-top: 2rem;
}

.btn-save, .btn-cancel {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: var(--font-bold);
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

.btn-save {
    background-color: var(--primary-color);
    color: var(--surface-color);
}

.btn-save:hover {
    opacity: 0.9;
}

.btn-cancel {
    background-color: var(--border-color);
    color: var(--text-color);
}

.btn-cancel:hover {
    background-color: #c9d1d6;
}