:root {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    color: #1f2937;
    background: #f3f4f6;
    font-synthesis: none;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
}

button,
input {
    font: inherit;
}

button {
    cursor: pointer;
}

.app-shell {
    width: min(900px, calc(100% - 2rem));
    margin: 0 auto;
    padding: 2rem 0 4rem;
}

.topbar,
.section-heading,
.add-row,
.danger-zone,
.todo-item,
.tabs {
    display: flex;
    align-items: center;
}

.topbar,
.section-heading,
.danger-zone {
    justify-content: space-between;
}

.topbar {
    margin-bottom: 1.5rem;
}

h1,
h2,
h3,
p {
    margin-top: 0;
}

h1 {
    margin-bottom: 0.25rem;
    font-size: 2rem;
}

h2 {
    margin-bottom: 0;
}

.muted {
    color: #6b7280;
}

.card {
    background: #fff;
    border: 1px solid #d1d5db;
    border-radius: 14px;
    padding: 1.25rem;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.05);
}

.auth-card {
    width: min(440px, 100%);
    margin: 4rem auto 0;
}

.tabs {
    gap: 0.5rem;
    margin-bottom: 1.25rem;
}

.tab {
    flex: 1;
    background: transparent;
    color: #4b5563;
    border: 1px solid #d1d5db;
}

.tab.active {
    background: #111827;
    color: white;
    border-color: #111827;
}

form {
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
}

label {
    font-weight: 600;
}

input {
    width: 100%;
    padding: 0.8rem 0.9rem;
    border: 1px solid #c7ccd4;
    border-radius: 9px;
    outline: none;
    background: white;
}

input:focus {
    border-color: #111827;
    box-shadow: 0 0 0 3px rgba(17, 24, 39, 0.1);
}

button {
    border: 0;
    border-radius: 9px;
    padding: 0.75rem 1rem;
    background: #111827;
    color: white;
    font-weight: 600;
}

button:hover {
    opacity: 0.9;
}

button:disabled {
    cursor: not-allowed;
    opacity: 0.55;
}

button.secondary {
    background: #e5e7eb;
    color: #111827;
}

button.danger {
    background: #b91c1c;
}

.hidden {
    display: none !important;
}

.add-card {
    margin-bottom: 1.75rem;
}

.add-row {
    gap: 0.75rem;
}

.add-row input {
    flex: 1;
}

.section-heading {
    margin-bottom: 1rem;
}

.todo-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    min-height: 4rem;
}

.todo-item {
    gap: 0.85rem;
    padding: 1rem;
    background: white;
    border: 1px solid #d1d5db;
    border-radius: 12px;
}

.todo-item.done .todo-text {
    color: #6b7280;
    text-decoration: line-through;
}

.todo-check {
    width: 1.2rem;
    height: 1.2rem;
    flex: 0 0 auto;
}

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

.todo-text {
    margin: 0;
    overflow-wrap: anywhere;
}

.todo-date {
    margin-top: 0.25rem;
    margin-bottom: 0;
    font-size: 0.82rem;
    color: #6b7280;
}

.todo-delete {
    background: transparent;
    color: #b91c1c;
    padding: 0.4rem 0.6rem;
}

.empty-state {
    padding: 2rem;
    border: 1px dashed #c7ccd4;
    border-radius: 12px;
    text-align: center;
    color: #6b7280;
}

.status {
    min-height: 1.5rem;
    margin: 0.75rem 0 0;
    color: #4b5563;
}

.status.error {
    color: #b91c1c;
}

.status.success {
    color: #166534;
}

.danger-zone {
    gap: 1rem;
    margin-top: 2rem;
    border-color: #fecaca;
}

.danger-zone h3,
.danger-zone p {
    margin-bottom: 0.3rem;
}

@media (max-width: 640px) {
    .app-shell {
        width: min(100% - 1rem, 900px);
        padding-top: 1rem;
    }

    .topbar,
    .danger-zone {
        align-items: flex-start;
        flex-direction: column;
    }

    .add-row {
        flex-direction: column;
        align-items: stretch;
    }

    .todo-item {
        align-items: flex-start;
    }
}