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

body {
    font-family:
        -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
    background-color: #f9fafb;
    color: #1f2937;
    line-height: 1.6;
    transition:
        background-color 0.3s,
        color 0.3s;
}

body.dark {
    background-color: #111827;
    color: #f9fafb;
}

.sidebar {
    width: 64px;
    height: 100vh;
    position: fixed;
    left: 0;
    top: 0;
    background: white;
    border-right: 1px solid #e5e7eb;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1.5rem 0;
    gap: 0.5rem;
    transition:
        background-color 0.3s,
        border-color 0.3s;
    z-index: 10;
}

body.dark .sidebar {
    background: #1f2937;
    border-right-color: #374151;
}

.sidebar-logo {
    width: 40px !important;
    height: 40px !important;
    max-width: 100%;
    margin-bottom: 0.5rem;
    object-fit: contain;
    flex-shrink: 0;
}

.sidebar-btn {
    width: 40px;
    height: 40px;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    background: #f3f4f6;
    color: #4b5563;
}

body.dark .sidebar-btn {
    background: #374151;
    color: #d1d5db;
}

.sidebar-btn:hover {
    background: #e5e7eb;
}
body.dark .sidebar-btn:hover {
    background: #4b5563;
}
.sidebar-btn.active {
    background: #3b82f6;
    color: white;
}

.spacer {
    flex: 1;
}

.main-wrapper {
    margin-left: 64px;
    display: flex;
    justify-content: center;
}

.container {
    width: 100%;
    max-width: 42rem;
    padding: 2rem 1rem;
}

h1 {
    text-align: center;
    font-size: 2.25rem;
    margin-bottom: 2rem;
}

.panel {
    background: white;
    border-radius: 0.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    padding: 1.5rem;
    margin-bottom: 2rem;
    animation: popIn 0.2s ease-out;
}

body.dark .panel {
    background: #1f2937;
}

@keyframes popIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.form-group {
    margin-bottom: 1rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid #d1d5db;
    border-radius: 0.5rem;
    font-size: 1rem;
    font-family: inherit;
}

body.dark .form-group input,
body.dark .form-group textarea {
    background: #374151;
    border-color: #4b5563;
    color: #f9fafb;
}

.datetime-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.input-with-icon {
    position: relative;
}
.input-icon {
    position: absolute;
    left: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    color: #9ca3af;
    pointer-events: none;
}

.input-with-icon input {
    padding-left: 2.5rem;
}

.btn-primary {
    width: 100%;
    padding: 0.75rem 1rem;
    background-color: #3b82f6;
    color: white;
    border: none;
    border-radius: 0.5rem;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
}

.tasks-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.task-card {
    background: white;
    border-radius: 0.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    padding: 1.25rem;
    position: relative;
}

body.dark .task-card {
    background: #1f2937;
}
.task-card.completed {
    opacity: 0.6;
}

.task-content {
    display: flex;
    gap: 1rem;
    align-items: start;
    padding-right: 2.5rem;
}

.checkbox {
    width: 24px;
    min-width: 24px;
    height: 24px;
    border: 2px solid #d1d5db;
    border-radius: 4px;
    cursor: pointer;
}

.checkbox.checked {
    background-color: #10b981;
    border-color: #10b981;
    position: relative;
}

.checkbox.checked::after {
    content: "✓";
    color: white;
    position: absolute;
    left: 4px;
    top: -2px;
}

.task-title {
    font-weight: 600;
}
.task-title.completed {
    text-decoration: line-through;
}
.task-description {
    font-size: 0.875rem;
    color: #6b7280;
}

.task-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.875rem;
    color: #6b7280;
    margin-top: 0.5rem;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.btn-delete {
    position: absolute;
    top: 1.25rem;
    right: 1rem;
    background: none;
    border: none;
    color: #9ca3af;
    cursor: pointer;
    transition: color 0.2s;
}

.btn-delete:hover {
    color: #ef4444;
}

.warning {
    font-weight: 600;
}
.warning.red {
    color: #dc2626;
}
.warning.orange {
    color: #f97316;
}
.warning.yellow {
    color: #ca8a04;
}

.empty-state {
    text-align: center;
    color: #9ca3af;
    padding: 3rem 0;
}

.hidden {
    display: none;
}

.settings-btn {
    width: 100%;
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.settings-btn-danger {
    background: #fef2f2;
    color: #dc2626;
}
body.dark .settings-btn-danger {
    background: rgba(220, 38, 38, 0.2);
    color: #fca5a5;
}

.footer-credit {
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid #e5e7eb;
    text-align: center;
    font-size: 0.875rem;
    color: #9ca3af;
}

@media (max-width: 640px) {
    .datetime-group {
        grid-template-columns: 1fr;
    }
    .main-wrapper {
        margin-left: 0;
        padding-bottom: 80px;
    }
    .sidebar {
        width: 100%;
        height: 60px;
        top: auto;
        bottom: 0;
        flex-direction: row;
        border-right: none;
        border-top: 1px solid #e5e7eb;
        padding: 0 1rem;
    }
    .sidebar-logo {
        margin-bottom: 0;
        margin-right: 0.5rem;
    }
}