/* === Acessibilidade === */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.skip-link {
    position: absolute;
    top: -100%;
    left: 50%;
    transform: translateX(-50%);
    background: #0056b3;
    color: #fff;
    padding: 12px 24px;
    z-index: 1000;
    font-size: 1rem;
    text-decoration: none;
    border-radius: 0 0 8px 8px;
    transition: top 0.2s;
}

.skip-link:focus {
    top: 0;
}

/* === Reset e Base === */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --color-bg: #f5f5f5;
    --color-surface: #ffffff;
    --color-primary: #0056b3;
    --color-primary-hover: #004494;
    --color-danger: #d32f2f;
    --color-danger-hover: #b71c1c;
    --color-success: #2e7d32;
    --color-text: #1a1a1a;
    --color-text-muted: #555555;
    --color-border: #cccccc;
    --color-focus: #ff9800;
    --radius: 8px;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* === Focus Visibility === */
*:focus-visible {
    outline: 3px solid var(--color-focus);
    outline-offset: 2px;
}

/* === Header === */
header {
    background: var(--color-surface);
    padding: 16px 24px;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

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

#user-nav {
    display: flex;
    align-items: center;
    gap: 12px;
}

#welcome-msg {
    font-weight: 600;
}

/* === Main === */
main {
    flex: 1;
    max-width: 720px;
    width: 100%;
    margin: 24px auto;
    padding: 0 16px;
}

section {
    background: var(--color-surface);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--shadow);
}

h2 {
    font-size: 1.25rem;
    margin-bottom: 16px;
    color: var(--color-text);
}

/* === Tabs === */
[role="tablist"] {
    display: flex;
    gap: 4px;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--color-border);
    padding-bottom: 0;
}

.tab-btn {
    background: transparent;
    border: none;
    padding: 10px 20px;
    font-size: 1rem;
    cursor: pointer;
    color: var(--color-text-muted);
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
    transition: color 0.2s, border-color 0.2s;
}

.tab-btn:hover {
    color: var(--color-primary);
}

.tab-btn.active,
.tab-btn[aria-selected="true"] {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
    font-weight: 600;
}

/* === Forms === */
.form-group {
    margin-bottom: 16px;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 6px;
    font-size: 0.95rem;
}

.optional {
    font-weight: 400;
    color: var(--color-text-muted);
    font-size: 0.85rem;
}

input[type="text"],
input[type="password"],
input[type="email"],
textarea {
    width: 100%;
    padding: 12px;
    font-size: 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius);
    background: var(--color-surface);
    color: var(--color-text);
    transition: border-color 0.2s;
    font-family: inherit;
}

input:focus,
textarea:focus {
    border-color: var(--color-primary);
}

input[aria-invalid="true"],
textarea[aria-invalid="true"] {
    border-color: var(--color-danger);
}

.error-msg {
    display: block;
    color: var(--color-danger);
    font-size: 0.85rem;
    margin-top: 4px;
    min-height: 1.2em;
}

button[type="submit"],
#logout-btn {
    background: var(--color-primary);
    color: #fff;
    border: none;
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius);
    cursor: pointer;
    transition: background 0.2s;
    width: 100%;
}

button[type="submit"]:hover,
#logout-btn:hover {
    background: var(--color-primary-hover);
}

#logout-btn {
    width: auto;
    padding: 8px 16px;
    font-size: 0.9rem;
}

/* === Filters === */
.filters {
    display: flex;
    gap: 8px;
    margin: 16px 0;
    flex-wrap: wrap;
}

.filter-btn {
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    padding: 8px 16px;
    font-size: 0.9rem;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.2s;
    color: var(--color-text);
}

.filter-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.filter-btn.active,
.filter-btn[aria-pressed="true"] {
    background: var(--color-primary);
    color: #fff;
    border-color: var(--color-primary);
}

/* === Task List === */
.task-count {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-bottom: 12px;
}

#task-list {
    list-style: none;
    padding: 0;
}

.task-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 16px;
    border: 2px solid var(--color-border);
    border-radius: var(--radius);
    margin-bottom: 12px;
    transition: border-color 0.2s;
}

.task-item:hover {
    border-color: var(--color-primary);
}

.task-item.completed {
    opacity: 0.7;
}

.task-item.completed .task-title {
    text-decoration: line-through;
    color: var(--color-text-muted);
}

.task-checkbox {
    flex-shrink: 0;
    width: 24px;
    height: 24px;
    margin-top: 2px;
    cursor: pointer;
    accent-color: var(--color-success);
}

.task-content {
    flex: 1;
    min-width: 0;
}

.task-title {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 4px;
    word-break: break-word;
}

.task-description {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-bottom: 8px;
    word-break: break-word;
}

.task-meta {
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

.task-actions {
    display: flex;
    gap: 8px;
    flex-shrink: 0;
}

.task-actions button {
    background: transparent;
    border: 2px solid var(--color-border);
    padding: 6px 12px;
    font-size: 0.85rem;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
}

.task-actions .edit-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.task-actions .delete-btn:hover {
    border-color: var(--color-danger);
    color: var(--color-danger);
}

/* === Empty State === */
.empty-state {
    text-align: center;
    color: var(--color-text-muted);
    padding: 32px;
    font-size: 1rem;
}

/* === Modal === */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    padding: 16px;
}

.modal-backdrop[hidden] {
    display: none;
}

.modal-content {
    background: var(--color-surface);
    border-radius: var(--radius);
    padding: 24px;
    max-width: 500px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.modal-content h2 {
    margin-top: 0;
    margin-bottom: 16px;
}

.modal-actions {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    margin-top: 20px;
}

.modal-actions button {
    padding: 10px 20px;
    font-size: 0.95rem;
    border-radius: var(--radius);
    cursor: pointer;
    font-weight: 600;
    border: 2px solid transparent;
}

#edit-cancel-btn {
    background: transparent;
    color: var(--color-text);
    border-color: var(--color-border) !important;
}

#edit-cancel-btn:hover {
    border-color: var(--color-primary) !important;
    color: var(--color-primary);
}

#edit-save-btn {
    background: var(--color-primary);
    color: #fff;
}

#edit-save-btn:hover {
    background: var(--color-primary-hover);
}

/* === Footer === */
footer {
    text-align: center;
    padding: 16px;
    color: var(--color-text-muted);
    font-size: 0.85rem;
}

/* === Responsive === */
@media (max-width: 600px) {
    header {
        flex-direction: column;
        align-items: flex-start;
    }

    .task-item {
        flex-direction: column;
    }

    .task-actions {
        align-self: flex-end;
    }
}