/* ==========================================================================
   Flowboard styles
   Mobile-first: base rules target small screens, media queries add the
   desktop layout. Class names follow BEM (block__element--modifier).
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Design tokens
   -------------------------------------------------------------------------- */
:root {
  /* Colours */
  --color-bg: #f4f6fb;
  --color-surface: #ffffff;
  --color-column: #eceff7;
  --color-border: #dfe3ee;
  --color-text: #1f2937;
  --color-text-muted: #64748b;
  --color-primary: #4f46e5;
  --color-primary-hover: #4338ca;
  --color-danger: #dc2626;
  --color-danger-hover: #b91c1c;
  --color-danger-text: #dc2626;
  --color-focus: #6366f1;
  --color-drop-target: #e0e7ff;

  /* Priority labels: soft background + dark text keeps contrast above 4.5:1 */
  --color-low-bg: #dcfce7;
  --color-low-text: #166534;
  --color-medium-bg: #fef3c7;
  --color-medium-text: #92400e;
  --color-high-bg: #fee2e2;
  --color-high-text: #991b1b;

  /* Column accent dots */
  --color-todo: #94a3b8;
  --color-in-progress: #3b82f6;
  --color-done: #22c55e;

  /* Typography */
  --font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-size-sm: 0.8125rem;
  --font-size-base: 0.9375rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;

  /* Spacing scale */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;

  /* Shape & depth */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-pill: 999px;
  --shadow-sm: 0 1px 2px rgb(15 23 42 / 0.06), 0 1px 3px rgb(15 23 42 / 0.08);
  --shadow-md: 0 4px 12px rgb(15 23 42 / 0.1);
  --shadow-lg: 0 20px 40px rgb(15 23 42 / 0.2);

  --transition: 150ms ease;

  /* Tells the browser to draw native controls (date picker, scrollbars) to match */
  color-scheme: light;
}

/* Night mode only swaps colour tokens: every component already reads its
   colours from variables, so no component styles need dark overrides.
   data-theme is set by js/themeInit.js before the page first paints. */
:root[data-theme="dark"] {
  --color-bg: #0b1120;
  --color-surface: #1e293b;
  --color-column: #131c2e;
  --color-border: #334155;
  --color-text: #e2e8f0;
  --color-text-muted: #94a3b8;
  --color-danger-text: #f87171;
  --color-focus: #818cf8;
  --color-drop-target: #1e1b4b;

  /* Translucent tints read as soft colour on a dark surface; light text keeps contrast */
  --color-low-bg: rgb(34 197 94 / 0.16);
  --color-low-text: #86efac;
  --color-medium-bg: rgb(245 158 11 / 0.16);
  --color-medium-text: #fcd34d;
  --color-high-bg: rgb(239 68 68 / 0.16);
  --color-high-text: #fca5a5;

  --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.3), 0 1px 3px rgb(0 0 0 / 0.4);
  --shadow-md: 0 4px 12px rgb(0 0 0 / 0.5);
  --shadow-lg: 0 20px 40px rgb(0 0 0 / 0.6);

  color-scheme: dark;
}

/* --------------------------------------------------------------------------
   2. Base & reset
   -------------------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg);
}

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

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

button {
  cursor: pointer;
}

/* One consistent, highly visible focus ring for keyboard users only */
:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

/* --------------------------------------------------------------------------
   3. Utilities
   -------------------------------------------------------------------------- */
/* Hides content visually while keeping it available to screen readers */
.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;
}

.sprite {
  display: none;
}

.icon {
  width: 1rem;
  height: 1rem;
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   4. Buttons & form controls
   -------------------------------------------------------------------------- */
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  font-weight: 600;
  white-space: nowrap;
  transition: background-color var(--transition), border-color var(--transition);
}

.button--primary {
  background: var(--color-primary);
  color: #fff;
}

.button--primary:hover {
  background: var(--color-primary-hover);
}

.button--ghost {
  background: var(--color-surface);
  border-color: var(--color-border);
}

.button--ghost:hover {
  border-color: var(--color-text-muted);
}

.button--danger {
  background: var(--color-danger);
  color: #fff;
}

.button--danger:hover {
  background: var(--color-danger-hover);
}

.input {
  width: 100%;
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: border-color var(--transition);
}

.input:hover {
  border-color: var(--color-text-muted);
}

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

.input--textarea {
  resize: vertical;
}

.input--search {
  padding-left: 2.25rem;
  /* Magnifier drawn as a background so the input needs no extra wrapper markup */
  background: var(--color-surface) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round'%3E%3Ccircle cx='11' cy='11' r='7'/%3E%3Cpath d='M20 20l-4-4'/%3E%3C/svg%3E") no-repeat 0.75rem center / 1rem;
}

/* --------------------------------------------------------------------------
   5. Header
   -------------------------------------------------------------------------- */
.header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.header__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
  max-width: 1280px;
  margin: 0 auto;
  padding: var(--space-4);
}

.header__title {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-right: auto;
  font-size: var(--font-size-xl);
  letter-spacing: -0.02em;
}

/* Three bars of decreasing height: a tiny Kanban board as the logo */
.header__logo {
  width: 1.75rem;
  height: 1.75rem;
  border-radius: var(--radius-sm);
  background:
    linear-gradient(#fff, #fff) left 22% top 0.375rem / 16% 50% no-repeat,
    linear-gradient(#fff, #fff) left 50% top 0.375rem / 16% 35% no-repeat,
    linear-gradient(#fff, #fff) left 78% top 0.375rem / 16% 22% no-repeat,
    var(--color-primary);
}

.header__search {
  order: 3;
  flex-basis: 100%;
}

.header__actions {
  display: flex;
  gap: var(--space-2);
}

/* Square icon button: shows a moon in day mode and a sun in night mode */
.theme-toggle {
  width: 2.625rem;
  padding: 0;
}

.theme-toggle .icon {
  width: 1.25rem;
  height: 1.25rem;
}

.theme-toggle[aria-pressed="false"] .theme-toggle__sun,
.theme-toggle[aria-pressed="true"] .theme-toggle__moon {
  display: none;
}

/* --------------------------------------------------------------------------
   6. Board & columns
   -------------------------------------------------------------------------- */
.board {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  max-width: 1280px;
  margin: 0 auto;
  padding: var(--space-4);
}

.column {
  display: flex;
  flex-direction: column;
  padding: var(--space-3);
  background: var(--color-column);
  border: 2px dashed transparent;
  border-radius: var(--radius-lg);
  transition: background-color var(--transition), border-color var(--transition);
}

.column--drop-target {
  background: var(--color-drop-target);
  border-color: var(--color-primary);
}

.column__header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-2) var(--space-3);
}

.column__title {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-base);
  font-weight: 700;
}

/* Coloured status dot before each column title */
.column__title::before {
  content: "";
  width: 0.625rem;
  height: 0.625rem;
  border-radius: 50%;
  background: var(--column-accent, var(--color-todo));
}

.column[data-status="in-progress"] {
  --column-accent: var(--color-in-progress);
}

.column[data-status="done"] {
  --column-accent: var(--color-done);
}

.column__count {
  min-width: 1.5rem;
  padding: 0 var(--space-2);
  border-radius: var(--radius-pill);
  background: var(--color-surface);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  font-weight: 600;
  text-align: center;
}

.column__list {
  display: flex;
  flex-direction: column;
  flex-grow: 1;
  gap: var(--space-3);
  min-height: 6rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.column__empty {
  display: grid;
  place-items: center;
  flex-grow: 1;
  padding: var(--space-5) var(--space-4);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  text-align: center;
}

/* --------------------------------------------------------------------------
   7. Task card
   -------------------------------------------------------------------------- */
.card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-4);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  cursor: grab;
  transition: box-shadow var(--transition), opacity var(--transition), transform var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.card--dragging {
  opacity: 0.4;
  transform: scale(0.98);
}

.card__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
}

.card__title {
  font-size: var(--font-size-base);
  font-weight: 600;
  overflow-wrap: anywhere;
}

.card__description {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  overflow-wrap: anywhere;
  white-space: pre-line;
}

.card__due {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.card__due--overdue {
  color: var(--color-high-text);
  font-weight: 600;
}

.card__actions {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin-top: var(--space-1);
  padding-top: var(--space-2);
  border-top: 1px solid var(--color-border);
}

/* Push the move-right button to the far edge so arrows sit at each end */
.card__action--move-right {
  margin-left: auto;
}

.card__action {
  display: inline-grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  padding: 0;
  background: transparent;
  border: 0;
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  transition: background-color var(--transition), color var(--transition);
}

.card__action:hover:not(:disabled) {
  background: var(--color-column);
  color: var(--color-text);
}

.card__action--delete:hover:not(:disabled) {
  background: var(--color-high-bg);
  color: var(--color-danger-text);
}

.card__action:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

/* --------------------------------------------------------------------------
   8. Priority label
   -------------------------------------------------------------------------- */
.priority {
  padding: 0.125rem var(--space-2);
  border-radius: var(--radius-pill);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.priority--low {
  background: var(--color-low-bg);
  color: var(--color-low-text);
}

.priority--medium {
  background: var(--color-medium-bg);
  color: var(--color-medium-text);
}

.priority--high {
  background: var(--color-high-bg);
  color: var(--color-high-text);
}

/* --------------------------------------------------------------------------
   9. Dialogs & form fields
   -------------------------------------------------------------------------- */
.dialog {
  width: min(32rem, calc(100% - 2 * var(--space-4)));
  padding: 0;
  border: 0;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  /* Set explicitly: the browser default (Canvas) ignores our theme tokens */
  background: var(--color-surface);
  color: var(--color-text);
}

.dialog--small {
  width: min(24rem, calc(100% - 2 * var(--space-4)));
}

.dialog::backdrop {
  background: rgb(15 23 42 / 0.45);
  backdrop-filter: blur(2px);
}

.dialog__form {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-5);
}

.dialog__title {
  font-size: var(--font-size-lg);
}

.dialog__message {
  color: var(--color-text-muted);
  overflow-wrap: anywhere;
}

.dialog__actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.field {
  display: flex;
  flex-direction: column;
  flex: 1;
  gap: var(--space-1);
}

.field-row {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.field__label {
  font-size: var(--font-size-sm);
  font-weight: 600;
}

.field__required {
  color: var(--color-danger-text);
}

.field__hint {
  color: var(--color-text-muted);
  font-weight: 400;
}

.field__error {
  color: var(--color-danger-text);
  font-size: var(--font-size-sm);
}

/* --------------------------------------------------------------------------
   10. Larger screens
   -------------------------------------------------------------------------- */
@media (min-width: 640px) {
  .field-row {
    flex-direction: row;
  }
}

@media (min-width: 768px) {
  .header__inner {
    flex-wrap: nowrap;
    padding: var(--space-4) var(--space-5);
  }

  .header__title {
    margin-right: 0;
  }

  /* On wide screens the search sits between the title and the buttons */
  .header__search {
    order: 0;
    flex: 1;
    max-width: 24rem;
    margin-left: auto;
  }

  .board {
    grid-template-columns: repeat(3, 1fr);
    align-items: start;
    padding: var(--space-5);
    gap: var(--space-5);
  }

  .column {
    min-height: 24rem;
  }
}

/* --------------------------------------------------------------------------
   11. Motion preferences
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition: none !important;
  }
}