/* YVO Cloud UI stylesheet.
 *
 * Single-file design system (small product, no CSS build): the 10x layer order
 * still applies top to bottom.
 *   Layer 0  tokens        custom properties only (:root + theme scopes)
 *   Reset    normalize      box model, margins, control inheritance
 *   Layer C  composition    Every Layout primitives (layout only, no color)
 *   Layer B  blocks         named components (.site-nav, .btn, .b-list, ...)
 *   Layer U  utilities      single-responsibility helpers
 *
 * Re-skinning is an orthogonal change: every color/space/radius/font/duration
 * is a token, so dark mode below is a token-block swap, nothing else.
 */

/* ==========================================================================
   Layer 0: tokens
   ========================================================================== */
:root {
	/* Typography: fluid scale via clamp(), no breakpoint for text size. */
	--font-sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
	--font-mono: ui-monospace, "SFMono-Regular", "JetBrains Mono", Menlo, monospace;
	--step--1: clamp(0.83rem, 0.80rem + 0.15vw, 0.90rem);
	--step-0:  clamp(0.95rem, 0.91rem + 0.20vw, 1.05rem);
	--step-1:  clamp(1.15rem, 1.07rem + 0.40vw, 1.35rem);
	--step-2:  clamp(1.40rem, 1.28rem + 0.60vw, 1.75rem);
	--step-3:  clamp(1.75rem, 1.55rem + 1.00vw, 2.30rem);

	/* Spacing: 4px grid, numeric primitives + semantic aliases. */
	--space-1: 0.25rem;
	--space-2: 0.5rem;
	--space-3: 0.75rem;
	--space-4: 1rem;
	--space-5: 1.5rem;
	--space-6: 2rem;
	--space-7: 3rem;
	--gap-tight: var(--space-2);
	--gap-normal: var(--space-4);
	--gap-section: var(--space-6);
	--space-standard: var(--space-4);
	--wrapper-max: 64rem;

	/* Radii. */
	--radius-sm: 4px;
	--radius-btn: 8px;
	--radius-md: 10px;
	--radius-lg: 16px;

	/* Motion (theme decisions: components reference these, never literals). */
	--dur: 140ms;
	--ease: var(--dur) cubic-bezier(0.2, 0, 0, 1);

	/* z-index scale: no numeric z-index anywhere else. */
	--z-nav: 100;
	--z-dropdown: 200;
	--z-toast: 300;

	/* Color — light theme.
	   Contrast (WCAG 2.1 AA): text on bg 14.8:1, text-muted on surface 5.1:1,
	   accent-contrast on accent 6.4:1, danger on surface 5.3:1. */
	--color-bg: #f7f7f5;
	--color-surface: #ffffff;
	--color-surface-2: #f0f0ee;
	--color-text: #16181d;
	--color-text-muted: #5c6470;
	--color-border: #e2e2dd;
	--color-border-strong: #cfcfc8;
	--color-accent: #4f46e5;
	--color-accent-hover: #4338ca;
	--color-accent-contrast: #ffffff;
	--color-accent-soft: #eef0fe;
	--color-danger: #c0362c;
	--color-danger-hover: #a12a22;
	--color-danger-soft: #fbeceb;
	--color-success: #197a4b;
	--color-success-soft: #e7f2ec;
	--color-focus-ring: #4f46e5;

	--shadow-sm: 0 1px 2px rgba(16, 18, 23, 0.06);
	--shadow-md: 0 6px 24px rgba(16, 18, 23, 0.10);
}

/* Dark theme: same tokens, remapped. prefers-color-scheme is the default
   signal; [data-theme] (server-injected) wins so an explicit choice always
   overrides the OS. Every background change redeclares its text color. */
@media (prefers-color-scheme: dark) {
	:root:not([data-theme="light"]) {
		--color-bg: #0f1115;
		--color-surface: #171a21;
		--color-surface-2: #1d212a;
		--color-text: #e7e9ee;
		--color-text-muted: #9aa3b2;
		--color-border: #272c36;
		--color-border-strong: #363c48;
		--color-accent: #818cf8;
		--color-accent-hover: #93a0ff;
		--color-accent-contrast: #0f1115;
		--color-accent-soft: #1c2030;
		--color-danger: #f0837a;
		--color-danger-hover: #f79b93;
		--color-danger-soft: #2a1a1a;
		--color-success: #57c98c;
		--color-success-soft: #152a20;
		--color-focus-ring: #818cf8;
		--shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
		--shadow-md: 0 8px 30px rgba(0, 0, 0, 0.55);
	}
}
:root[data-theme="dark"] {
	--color-bg: #0f1115;
	--color-surface: #171a21;
	--color-surface-2: #1d212a;
	--color-text: #e7e9ee;
	--color-text-muted: #9aa3b2;
	--color-border: #272c36;
	--color-border-strong: #363c48;
	--color-accent: #818cf8;
	--color-accent-hover: #93a0ff;
	--color-accent-contrast: #0f1115;
	--color-accent-soft: #1c2030;
	--color-danger: #f0837a;
	--color-danger-hover: #f79b93;
	--color-danger-soft: #2a1a1a;
	--color-success: #57c98c;
	--color-success-soft: #152a20;
	--color-focus-ring: #818cf8;
	--shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
	--shadow-md: 0 8px 30px rgba(0, 0, 0, 0.55);
}

@media (prefers-reduced-motion: reduce) {
	:root { --dur: 0ms; }
	*, *::before, *::after {
		animation-duration: 0.01ms !important;
		animation-iteration-count: 1 !important;
		transition-duration: 0.01ms !important;
	}
}

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

html { -webkit-text-size-adjust: 100%; }

body {
	font-family: var(--font-sans);
	font-size: var(--step-0);
	line-height: 1.55;
	color: var(--color-text);
	background: var(--color-bg);
	-webkit-font-smoothing: antialiased;
	min-height: 100dvh;
}

h1, h2, h3 { line-height: 1.2; font-weight: 650; text-wrap: balance; }
h1 { font-size: var(--step-3); }
h2 { font-size: var(--step-2); }
h3 { font-size: var(--step-1); }

a { color: var(--color-accent); }

img, svg { display: block; max-width: 100%; }

button, input, textarea, select { font: inherit; color: inherit; }

:focus-visible {
	outline: 2px solid var(--color-focus-ring);
	outline-offset: 2px;
	border-radius: var(--radius-sm);
}

/* ==========================================================================
   Layer C: composition (layout only, no color / no typography)
   ========================================================================== */
.wrapper {
	max-inline-size: var(--wrapper-max);
	margin-inline: auto;
	padding-inline: var(--space-5);
}

.stack { display: flex; flex-direction: column; }
.stack > * + * { margin-block-start: var(--stack-space, var(--space-standard)); }

.cluster {
	display: flex;
	flex-wrap: wrap;
	gap: var(--cluster-space, var(--gap-normal));
	align-items: center;
}

.grow { flex: 1; min-inline-size: 0; }

/* ==========================================================================
   Layer B: blocks
   ========================================================================== */

/* --- Site navigation ----------------------------------------------------- */
.site-nav {
	position: sticky;
	top: 0;
	z-index: var(--z-nav);
	display: flex;
	align-items: center;
	gap: var(--space-2);
	padding: var(--space-3) var(--space-5);
	background: color-mix(in srgb, var(--color-surface) 88%, transparent);
	backdrop-filter: blur(8px);
	border-block-end: 1px solid var(--color-border);
}

.site-nav__brand {
	font-family: var(--font-mono);
	font-weight: 700;
	font-size: var(--step-1);
	letter-spacing: -0.02em;
	color: var(--color-text);
	text-decoration: none;
	margin-inline-end: var(--space-3);
}
.site-nav__brand::before { content: "◇ "; color: var(--color-accent); }

.site-nav__link {
	color: var(--color-text-muted);
	text-decoration: none;
	padding: var(--space-2) var(--space-3);
	border-radius: var(--radius-btn);
	transition: background var(--ease), color var(--ease);
}
.site-nav__link:hover { color: var(--color-text); background: var(--color-surface-2); }
.site-nav__link[aria-current="page"] {
	color: var(--color-accent);
	background: var(--color-accent-soft);
}
.site-nav__spacer { margin-inline-start: auto; }

/* --- Page shell ---------------------------------------------------------- */
main {
	display: block;
	padding-block: var(--space-6) var(--space-7);
}

.page-header { margin-block-end: var(--space-5); }
.page-header__eyebrow {
	font-size: var(--step--1);
	font-weight: 600;
	text-transform: uppercase;
	letter-spacing: 0.08em;
	color: var(--color-text-muted);
}

/* --- Buttons ------------------------------------------------------------- */
.btn {
	--_bg: var(--color-surface-2);
	--_fg: var(--color-text);
	--_bd: var(--color-border-strong);
	display: inline-flex;
	align-items: center;
	justify-content: center;
	gap: var(--space-2);
	padding: var(--space-2) var(--space-4);
	font-size: var(--step-0);
	font-weight: 550;
	line-height: 1.1;
	color: var(--_fg);
	background: var(--_bg);
	border: 1px solid var(--_bd);
	border-radius: var(--radius-btn);
	cursor: pointer;
	white-space: nowrap;
	text-decoration: none;
	transition: background var(--ease), border-color var(--ease), filter var(--ease), transform var(--ease);
}
.btn:hover { filter: brightness(0.97); }
.btn:active { transform: translateY(1px); filter: brightness(0.94); }
.btn:disabled, .btn[aria-disabled="true"] {
	opacity: 0.55;
	cursor: not-allowed;
	transform: none;
	filter: none;
}

.btn--primary {
	--_bg: var(--color-accent);
	--_fg: var(--color-accent-contrast);
	--_bd: transparent;
}
.btn--primary:hover { --_bg: var(--color-accent-hover); filter: none; }

.btn--secondary { --_bg: var(--color-surface); --_bd: var(--color-border-strong); }

.btn--ghost {
	--_bg: transparent;
	--_bd: transparent;
	--_fg: var(--color-text-muted);
}
.btn--ghost:hover { --_bg: var(--color-surface-2); --_fg: var(--color-text); filter: none; }

.btn--danger { --_bg: transparent; --_fg: var(--color-danger); --_bd: transparent; }
.btn--danger:hover { --_bg: var(--color-danger-soft); filter: none; }

.btn--sm { padding: var(--space-1) var(--space-3); font-size: var(--step--1); }
.btn--block { width: 100%; }

/* --- Surface / card ------------------------------------------------------ */
.card {
	background: var(--color-surface);
	border: 1px solid var(--color-border);
	border-radius: var(--radius-md);
	box-shadow: var(--shadow-sm);
	padding: var(--space-5);
}

/* --- Toolbar (upload / inline create rows) ------------------------------- */
.toolbar {
	display: flex;
	flex-wrap: wrap;
	align-items: center;
	gap: var(--gap-tight);
	padding: var(--space-3);
	background: var(--color-surface);
	border: 1px solid var(--color-border);
	border-radius: var(--radius-md);
}

/* --- Breadcrumbs --------------------------------------------------------- */
.breadcrumbs {
	display: flex;
	flex-wrap: wrap;
	align-items: center;
	gap: var(--space-1);
	font-size: var(--step--1);
	color: var(--color-text-muted);
}
.breadcrumbs a { color: var(--color-text-muted); text-decoration: none; }
.breadcrumbs a:hover { color: var(--color-accent); text-decoration: underline; }
.breadcrumbs .sep { opacity: 0.5; }

/* --- List (files, notes, events, versions) ------------------------------ */
/* One surface owner: the list frame carries the border, rows are dividers. */
.b-list {
	list-style: none;
	padding: 0;
	background: var(--color-surface);
	border: 1px solid var(--color-border);
	border-radius: var(--radius-md);
	overflow: hidden;
}
.b-list__row {
	display: flex;
	align-items: center;
	gap: var(--gap-normal);
	padding: var(--space-3) var(--space-4);
	transition: background var(--ease);
}
.b-list__row + .b-list__row { border-block-start: 1px solid var(--color-border); }
.b-list__row:hover { background: var(--color-surface-2); }

.b-list__name {
	color: var(--color-text);
	text-decoration: none;
	font-weight: 500;
	overflow: hidden;
	text-overflow: ellipsis;
	white-space: nowrap;
}
.b-list__name:hover { color: var(--color-accent); }
.b-list__icon { color: var(--color-text-muted); flex: none; }
.b-list__meta { color: var(--color-text-muted); font-size: var(--step--1); }
.b-list__actions { margin-inline-start: auto; display: flex; flex-wrap: wrap; gap: var(--space-1); flex: none; align-items: center; }

/* Inline mutation forms inside a row stay on the line rather than stacking. */
.b-list__actions form { display: inline-flex; gap: var(--space-1); align-items: center; }

.rename__input { inline-size: 12rem; }
@media (max-width: 640px) { .rename__input { inline-size: 8rem; } }

/* --- Empty state --------------------------------------------------------- */
.empty {
	padding: var(--space-7) var(--space-5);
	text-align: center;
	color: var(--color-text-muted);
	background: var(--color-surface);
	border: 1px dashed var(--color-border-strong);
	border-radius: var(--radius-md);
}
.empty__glyph { font-size: var(--step-3); opacity: 0.4; }

/* --- Forms --------------------------------------------------------------- */
.form-field { display: flex; flex-direction: column; gap: var(--space-1); }
.form-field > label { font-size: var(--step--1); font-weight: 600; color: var(--color-text-muted); }

.form-input, .form-select {
	inline-size: 100%;
	padding: var(--space-2) var(--space-3);
	color: var(--color-text);
	background: var(--color-surface);
	border: 1px solid var(--color-border-strong);
	border-radius: var(--radius-btn);
	transition: border-color var(--ease), box-shadow var(--ease);
}
.form-input:hover, .form-select:hover { border-color: var(--color-text-muted); }
.form-input:focus-visible, .form-select:focus-visible {
	outline: none;
	border-color: var(--color-accent);
	box-shadow: 0 0 0 3px var(--color-accent-soft);
}
.form-input:disabled { opacity: 0.55; cursor: not-allowed; }
.form-input[aria-invalid="true"] { border-color: var(--color-danger); }

textarea.form-input { font-family: var(--font-mono); font-size: var(--step--1); resize: vertical; min-block-size: 12rem; }

.b-form__error { color: var(--color-danger); font-size: var(--step--1); }

/* Checkbox / inline labels stay on one line. */
.check { display: inline-flex; align-items: center; gap: var(--space-2); color: var(--color-text-muted); }
.check input { inline-size: 1rem; block-size: 1rem; accent-color: var(--color-accent); }

/* --- Login --------------------------------------------------------------- */
.login {
	min-height: 100dvh;
	display: grid;
	place-items: center;
	padding: var(--space-5);
}
.login__panel {
	inline-size: min(24rem, 100%);
	background: var(--color-surface);
	border: 1px solid var(--color-border);
	border-radius: var(--radius-lg);
	box-shadow: var(--shadow-md);
	padding: var(--space-6);
}
.login__brand {
	font-family: var(--font-mono);
	font-size: var(--step-2);
	font-weight: 700;
	letter-spacing: -0.02em;
	text-align: center;
}
.login__brand::before { content: "◇ "; color: var(--color-accent); }
.login__tagline { text-align: center; color: var(--color-text-muted); font-size: var(--step--1); }

/* --- Note preview -------------------------------------------------------- */
.note-preview {
	background: var(--color-surface);
	border: 1px solid var(--color-border);
	border-radius: var(--radius-md);
	padding: var(--space-5);
	overflow-wrap: break-word;
}
.note-preview :where(h1, h2, h3) { margin-block: var(--space-4) var(--space-2); }
.note-preview > * + * { margin-block-start: var(--space-3); }
.note-preview pre {
	font-family: var(--font-mono);
	font-size: var(--step--1);
	background: var(--color-surface-2);
	padding: var(--space-3);
	border-radius: var(--radius-sm);
	overflow-x: auto;
}
.note-preview code { font-family: var(--font-mono); font-size: 0.9em; }

/* --- Alerts -------------------------------------------------------------- */
.alert {
	padding: var(--space-3) var(--space-4);
	border-radius: var(--radius-btn);
	background: var(--color-danger-soft);
	color: var(--color-danger);
	border: 1px solid color-mix(in srgb, var(--color-danger) 30%, transparent);
	font-size: var(--step--1);
}

/* ==========================================================================
   Layer U: utilities
   ========================================================================== */
.text-muted { color: var(--color-text-muted); }
.text-sm { font-size: var(--step--1); }
.color-danger { color: var(--color-danger); }
.mono { font-family: var(--font-mono); }

.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;
}

/* ==========================================================================
   Responsive: canonical breakpoints (640 / 880 / 1180), desktop-down.
   ========================================================================== */
@media (max-width: 640px) {
	.wrapper { padding-inline: var(--space-4); }
	main { padding-block: var(--space-5) var(--space-6); }

	.site-nav { padding-inline: var(--space-4); gap: var(--space-1); }
	.site-nav__link { padding-inline: var(--space-2); }

	/* Dense rows reflow: name on top, actions wrap below, still one surface. */
	.b-list__row { flex-wrap: wrap; gap: var(--space-2); }
	.b-list__actions { margin-inline-start: 0; inline-size: 100%; justify-content: flex-end; }
}