@import url('https://fonts.googleapis.com/css2?family=Source+Sans+3:wght@400;500;600&family=Source+Serif+4:wght@400;500;600&display=swap');

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

:root {
    /* Colors - using oklch for perceptually uniform color spaces */
    --color-primary: oklch(0.55 0.2 255);
    --color-primary-hover: oklch(0.58 0.2 255);
    --color-primary-active: oklch(0.45 0.2 255);
    --color-danger: oklch(0.55 0.2 40);

    --color-text: oklch(0.15 0 0);
    --color-text-muted: oklch(0.55 0 0);

    --color-bg: oklch(0.98 0 0);
    --color-border: oklch(0.89 0 0);
    --color-surface: oklch(0.96 0 0);

    /* Semantic mappings */
    --color-input-border: var(--color-border);
    --color-input-focus: var(--color-primary);
    --color-hover-bg: oklch(0.92 0 0);
    --color-active-bg: oklch(0.88 0 0);
    --color-focus-ring: oklch(0.55 0.2 255 / 0.3);
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
    :root {
        --color-primary: oklch(0.65 0.2 255);
        --color-primary-hover: oklch(0.70 0.2 255);
        --color-primary-active: oklch(0.55 0.2 255);
        --color-danger: oklch(0.65 0.2 40);

        --color-text: oklch(0.96 0 0);
        --color-text-muted: oklch(0.70 0 0);

        --color-bg: oklch(0.13 0 0);
        --color-border: oklch(0.28 0 0);
        --color-surface: oklch(0.16 0 0);

        --color-input-border: oklch(0.28 0 0);
        --color-input-focus: var(--color-primary);
        --color-hover-bg: oklch(0.20 0 0);
        --color-active-bg: oklch(0.24 0 0);
        --color-focus-ring: oklch(0.65 0.2 255 / 0.3);
    }
}

body {
    font-family: 'Source Sans 3', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 60px 40px;
}

/* Header */
.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 48px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--color-border);
}

.header h1 {
    font-family: 'Source Serif 4', Georgia, 'Times New Roman', serif;
    font-size: 28px;
    font-weight: 600;
    color: var(--color-text);
    letter-spacing: -0.5px;
}

/* Loading & Error */
.loading {
    text-align: center;
    padding: 60px;
    color: var(--color-text-muted);
    font-size: 14px;
}

.error {
    color: var(--color-danger);
    padding: 16px 0;
    margin-bottom: 24px;
    font-size: 14px;
}

/* Note Form */
.note-form {
    background: var(--color-bg);
}

.form-group {
    margin-bottom: 24px;
}

.form-control {
    width: 100%;
    padding: 14px 0;
    border: none;
    border-bottom: 1px solid var(--color-border);
    font-size: 18px;
    font-family: inherit;
    color: var(--color-text);
    background: transparent;
    transition: border-color 0.2s ease;
}

.form-control::placeholder {
    color: var(--color-text-muted);
}

.form-control:focus {
    outline: none;
    border-bottom-color: var(--color-primary);
}

.content-area {
    min-height: 320px;
    padding: 16px 0;
    border-bottom: 1px solid var(--color-border);
    resize: none;
    line-height: 1.7;
}

.content-area:focus {
    border-bottom-color: var(--color-primary);
}

.page-wrapper {
    min-height: 100vh;
}

/* Buttons */
.form-actions {
    display: flex;
    gap: 16px;
    justify-content: flex-end;
    padding-top: 24px;
}

.btn {
    padding: 12px 24px;
    border: none;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    border-radius: 24px;
    transition: all 0.2s ease;
    font-family: inherit;
}

.btn:focus {
    outline: none;
}

.btn:focus-visible {
    box-shadow: 0 0 0 3px var(--color-focus-ring);
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--color-primary-hover);
}

.btn-primary:active:not(:disabled) {
    background-color: var(--color-primary-active);
}

.btn-secondary {
    background-color: var(--color-surface);
    color: var(--color-text);
}

.btn-secondary:hover:not(:disabled) {
    background-color: var(--color-hover-bg);
}

.btn-secondary:active:not(:disabled) {
    background-color: var(--color-active-bg);
}

.btn-danger {
    background-color: var(--color-bg);
    color: var(--color-danger);
    border: 1px solid var(--color-danger);
}

.btn-danger:hover:not(:disabled) {
    background-color: var(--color-danger);
    color: var(--color-bg);
}

.btn-danger:active:not(:disabled) {
    background-color: var(--color-danger);
    filter: brightness(0.85);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Delete Confirmation */
.delete-confirm {
    display: none;
    align-items: center;
    gap: 12px;
    padding: 12px 0;
}

.delete-confirm.active {
    display: flex;
}

.delete-confirm-message {
    font-size: 14px;
    color: var(--color-text);
    flex: 1;
}

.delete-confirm-actions {
    display: flex;
    gap: 8px;
}

.delete-confirm .btn {
    padding: 8px 16px;
    font-size: 14px;
}

.delete-confirm .btn-cancel {
    background-color: var(--color-surface);
    color: var(--color-text);
}

.delete-confirm .btn-cancel:hover:not(:disabled) {
    background-color: var(--color-hover-bg);
}

.delete-confirm .btn-confirm-delete {
    background-color: var(--color-danger);
    color: var(--color-bg);
}

.delete-confirm .btn-confirm-delete:hover:not(:disabled) {
    opacity: 0.85;
}

/* Notes List */
.notes-list {
    display: flex;
    flex-direction: column;
    gap: 1px;
    background: var(--color-border);
    border-radius: 12px;
    overflow: hidden;
}

.note-item {
    background: var(--color-bg);
    padding: 20px 24px;
    cursor: pointer;
    transition: background-color 0.15s ease;
}

.note-item:hover {
    background-color: var(--color-surface);
}

.note-item:active {
    background-color: var(--color-active-bg);
}

.note-item:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: -2px;
}

.note-item h3 {
    font-size: 17px;
    font-weight: 500;
    margin-bottom: 6px;
    color: var(--color-text);
    letter-spacing: -0.2px;
}

.note-item .meta {
    font-size: 13px;
    color: var(--color-text-muted);
}

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

/* Empty State */
.empty-state {
    text-align: center;
    padding: 80px 20px;
}

.empty-state p:first-child {
    font-size: 21px;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 8px;
}

.empty-state p:last-child {
    font-size: 15px;
    color: var(--color-text-muted);
}

/* Responsive */
@media (max-width: 680px) {
    .container {
        padding: 32px 20px;
    }

    .header {
        flex-wrap: wrap;
        gap: 12px;
    }

    .header h1 {
        font-size: 22px;
        flex: 1 1 auto;
    }

    .header .btn-primary {
        flex: 0 0 auto;
    }

    .form-control {
        font-size: 17px;
    }

    .form-actions {
        flex-wrap: wrap;
    }

    .form-actions .btn {
        flex: 1;
    }

    .btn-secondary {
        order: 1;
    }

    .btn-danger {
        order: 2;
    }

    .btn-primary {
        order: 3;
        width: 100%;
        margin-top: 8px;
    }
}