/* ==========================================================================
   MEMORA — SHARED STYLESHEET
   Sitewide design system: colors, type, spacing, reset, and reusable
   components. Classes here have no page prefix (e.g. .nav-bar, .btn-primary).
   Page-specific stylesheets (e.g. home.css) layer on top of this file and
   prefix their own classes with the page name (e.g. .home-hero).
   ========================================================================== */


/* --------------------------------------------------------------------------
   1. ROOT VARIABLES
   -------------------------------------------------------------------------- */

:root {
  /* --- Colors --- */
  --primary: #2E5AA8;
  --accent: #D9A441;
  --bg: #F1EFEA;
  --surface: #FFFFFF;
  --text: #22252A;

  /* Derived shades, needed for hover/active/disabled states. Base colors
     above are exact; these are simple darker/lighter steps off them. */
  --primary-hover: #274B8F;   /* primary, one step darker */
  --primary-active: #1F3D73;  /* primary, two steps darker */
  --accent-hover: #C6922F;    /* accent, one step darker */
  --accent-active: #B07F22;   /* accent, two steps darker */
  --text-muted: #65686C;      /* text, lighter gray — helper/instructional text under a field */

  --tint-blue-faint: #E4EBF6;   /* faint blue tint, secondary button hover */
  --tint-blue-deeper: #C9D7EE;  /* deeper blue tint, secondary button active */

  --border-grey: #D8D5CF;       /* thin border, cards / form fields */
  --border-grey-dark: #ABA8A2;  /* form field border on hover */

  --disabled-bg: #CBCBCB;
  --disabled-text: #8A8A8A;
  --disabled-border: #B0B0B0;

  --error: #B3453D;  /* inline validation/error messages, Log In / Sign Up */

  /* --- Type scale --- */
  --font-size-heading: 24px;
  --font-weight-heading: 700;

  --font-size-body: 16px;
  --font-weight-body: 400;

  --font-size-small: 14px;
  --font-weight-small: 400;

  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Helvetica, Arial, sans-serif;

  /* --- Spacing, base unit 8px --- */
  --space-tight: 8px;      /* 1x, between closely related items */
  --space-standard: 24px;  /* 3x, between sections or blocks */

  /* Page edge padding: smaller below 768px, larger at 768px and up. */
  --space-edge-mobile: 20px;
  --space-edge-desktop: 56px;

  /* Content width cap: keeps page content from stretching edge to edge on
     wide screens. .page-container centers within this at 768px and up. */
  --content-max-width: 1200px;

  /* Corner radius */
  --radius-sm: 6px;  /* buttons, tabs, form fields */
  --radius-md: 8px;  /* cards, the flashcard, the card block */

  /* --- Motion --- */
  --transition-fast: 0.15s ease;
}


/* --------------------------------------------------------------------------
   2. BASE / RESET
   -------------------------------------------------------------------------- */

* {
  box-sizing: border-box;
}

html {
  height: 100%;
}

body {
  margin: 0;
  min-height: 100%;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-family);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
}

h1, h2 {
  font-size: var(--font-size-heading);
  font-weight: var(--font-weight-heading);
  color: var(--text);
  margin: 0;
}

img {
  max-width: 100%;
  height: auto;
}

/* Visible focus ring, kept on every element. Never remove this. */
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

/* Respect "reduce motion" OS setting: every transition/animation on the
   site collapses to effectively instant instead of forcing motion on
   people who've asked their device not to. */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}


/* --------------------------------------------------------------------------
   3. PAGE CONTAINER (edge padding)
   -------------------------------------------------------------------------- */

.page-container {
  flex: 1 0 auto;
  padding-left: var(--space-edge-mobile);
  padding-right: var(--space-edge-mobile);
}


/* --------------------------------------------------------------------------
   4. COMPONENTS
   -------------------------------------------------------------------------- */

/* --- Nav bar --- */
/* Logged out: Home, Log In / Sign Up — logo only.
   Logged in: Create Deck, Study Mode — logo only.
   Logged in: My Decks — logo + account link (the only page with Log Out). */
.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--surface);
  border-bottom: 1px solid var(--border-grey);
  padding: var(--space-tight) var(--space-edge-mobile);
}

.nav-bar__logo {
  display: inline-flex;
  align-items: center;
  gap: var(--space-tight);
  font-size: var(--font-size-heading);
  font-weight: var(--font-weight-heading);
  color: var(--text);
  text-decoration: none;
  transition: color var(--transition-fast);
}

/* Logo mark beside the "Memora" text. Decorative: the link text names it. */
.nav-bar__logo-img {
  width: 32px;
  height: 32px;
}

.nav-bar__logo:hover {
  color: var(--primary);
}

.nav-bar__logo:active {
  color: var(--primary-active);
}

.nav-bar__account-link {
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  color: var(--text);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.nav-bar__account-link:hover {
  color: var(--primary);
}

.nav-bar__account-link:active {
  color: var(--primary-active);
}
/* No disabled state: logged-out pages simply omit the account link. */


/* --- Primary button --- */
/* Home (Sign Up), Log In / Sign Up (Log In submit), Create Deck (Save deck) */
.btn-primary {
  display: inline-block;
  background: var(--primary);
  color: #FFFFFF;
  border: none;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  font-family: var(--font-family);
  padding: var(--space-tight) var(--space-standard);
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  transition: background-color var(--transition-fast);
}

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

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

.btn-primary:disabled {
  background: var(--disabled-bg);
  color: var(--disabled-text);
  cursor: not-allowed;
}


/* --- Secondary button, text only --- */
/* Home (Log In), Create Deck (Add another card), Study Mode (Back to My
   Decks), Log In / Sign Up (Back to Home) */
.btn-secondary {
  display: inline-block;
  background: var(--surface);
  color: var(--primary);
  border: 1px solid var(--primary);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  font-family: var(--font-family);
  padding: var(--space-tight) var(--space-standard);
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  transition: background-color var(--transition-fast);
}

.btn-secondary:hover {
  background: var(--tint-blue-faint);
}

.btn-secondary:active {
  background: var(--tint-blue-deeper);
}

.btn-secondary:disabled {
  border-color: var(--disabled-border);
  color: var(--disabled-text);
  cursor: not-allowed;
}

/* --- Secondary button, icon plus text --- */
/* Study Mode: Mark Reviewed, Mark Not Yet Reviewed, Previous card, Next card */
.btn-secondary-icon {
  display: inline-flex;
  align-items: center;
  gap: var(--space-tight);
  background: var(--surface);
  color: var(--primary);
  border: 1px solid var(--primary);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  font-family: var(--font-family);
  padding: var(--space-tight) var(--space-standard);
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.btn-secondary-icon svg {
  width: 16px;
  height: 16px;
}

.btn-secondary-icon:hover {
  background: var(--tint-blue-faint);
}

.btn-secondary-icon:active {
  background: var(--tint-blue-deeper);
}

.btn-secondary-icon:disabled {
  border-color: var(--disabled-border);
  color: var(--disabled-text);
  cursor: not-allowed;
}


/* --- Accent button --- */
/* My Decks (Create new deck) only. One accent button, sitewide. */
.btn-accent {
  display: inline-block;
  background: var(--accent);
  color: var(--text);
  border: none;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  font-family: var(--font-family);
  padding: var(--space-tight) var(--space-standard);
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  transition: background-color var(--transition-fast);
}

.btn-accent:hover {
  background: var(--accent-hover);
}

.btn-accent:active {
  background: var(--accent-active);
}
/* No disabled state: not expected in current wireframes. */


/* --- Tab switcher --- */
/* Log In / Sign Up page. Stays side by side at every screen size. */
.tab-switcher {
  display: flex;
  gap: var(--space-tight);
}

.tab {
  padding: var(--space-tight) var(--space-standard);
  border: 1px solid var(--primary);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--primary);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  font-family: var(--font-family);
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.tab:hover {
  background: var(--tint-blue-faint);
}

/* Selected tab: filled dark, white text (this is the "active" result of
   clicking a tab). */
.tab.is-selected {
  background: var(--text);
  border-color: var(--text);
  color: #FFFFFF;
}
/* Not applicable: no disabled state for tabs. */


/* --- Deck card --- */
/* My Decks page. Whole box is clickable. */
.deck-card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border-grey);
  border-radius: var(--radius-md);
  padding: var(--space-standard);
  cursor: pointer;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.14);
  text-decoration: none;
  color: inherit;
  transition: box-shadow var(--transition-fast);
}

.deck-card:hover,
.deck-card:has(:focus-visible) {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.18);
}

.deck-card:active {
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.14);
}

.deck-card__title {
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  color: var(--text);
}

.deck-card__progress {
  font-size: var(--font-size-small);
  font-weight: var(--font-weight-small);
  color: var(--text);
}
/* Not used: every deck shown is clickable, so no disabled state. */


/* --- Flashcard --- */
/* Study Mode. Tap or click to flip between question and answer. */
.flashcard {
  position: relative;
  display: block;
  background: var(--surface);
  border-radius: var(--radius-md);
  padding: var(--space-standard);
  text-align: center;
  cursor: pointer;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.08);
  transition: box-shadow var(--transition-fast);
}

.flashcard:hover {
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.14);
}

.flashcard:active {
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.08);
}

.flashcard__flip-icon {
  position: absolute;
  top: var(--space-tight);
  right: var(--space-tight);
  width: 20px;
  height: 20px;
}

.flashcard__question,
.flashcard__answer {
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  color: var(--text);
}

/* Flipped state instead of a disabled state. */
.flashcard:not(.is-flipped) .flashcard__answer {
  display: none;
}

.flashcard.is-flipped .flashcard__question {
  display: none;
}


/* --- Form field --- */
/* Log In / Sign Up (Email, Password); Create Deck (Deck title, Question,
   Answer). Each repeating Question/Answer pair gets its own label pair. */
.form-field {
  display: flex;
  flex-direction: column;
  gap: var(--space-tight);
}

.form-field label {
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  color: var(--text);
}

/* Marks a field's label as required, e.g. `<label>Email <span
   class="required-mark">*</span></label>`. */
.required-mark {
  color: var(--error);
}

/* One legend for a form where every field is required (Log In / Sign Up):
   states the asterisk's meaning once, up top, instead of repeating it on
   every label. Place as the form's first child, e.g. `<p class=
   "required-note">Fields with <span class="required-mark">*</span> are
   required.</p>`. Same color as a field label, not muted: this is the
   text that explains the labels' own asterisks, so it reads as part of
   that same group rather than secondary helper text. */
.required-note {
  margin: 0;
  font-size: var(--font-size-small);
  font-weight: var(--font-weight-small);
  color: var(--text);
}

.form-field input,
.form-field textarea {
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-body);
  font-family: var(--font-family);
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border-grey);
  border-radius: var(--radius-sm);
  padding: var(--space-tight);
  transition: border-color var(--transition-fast);
}

.form-field input:hover,
.form-field textarea:hover {
  border-color: var(--border-grey-dark);
}

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

.form-field input:disabled,
.form-field textarea:disabled {
  background: var(--disabled-bg);
  color: var(--disabled-text);
  cursor: not-allowed;
}

/* --- Form error --- */
/* Log In / Sign Up (validation, duplicate account, login failure).
   Always present (never `hidden`) and given a minimum height so the
   space is reserved up front — a message appearing doesn't push the
   buttons below it further down the page. Sized for two lines: the
   username rule's message is long enough to wrap, and everything
   shorter just sits centered inside the same reserved space. */
.form-error {
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 36px;
  text-align: center;
  font-size: var(--font-size-small);
  font-weight: var(--font-weight-small);
  color: var(--error);
}

/* Helper text: Log In / Sign Up's field guidance, Create Deck's field
   helper text, Study Mode's progress line (total cards, reviewed, not
   yet reviewed). Margin reset to 0: as a <p> nested in .form-field's
   flex column, the browser's default paragraph margin would add extra
   space on top of .form-field's own `gap`, doubling up the spacing. */
.helper-text {
  margin: 0;
  font-size: var(--font-size-small);
  font-weight: var(--font-weight-small);
  color: var(--text-muted);
}

/* Card block: one repeating Question/Answer pair on Create Deck. */
.card-block {
  border: 1px solid var(--border-grey);
  border-radius: var(--radius-md);
  padding: var(--space-standard);
  display: flex;
  flex-direction: column;
  gap: var(--space-tight);
  margin-bottom: var(--space-standard);
}


/* --- Footer --- */
/* All 5 pages. Static text, top border only. */
.footer {
  border-top: 1px solid var(--border-grey);
  padding: var(--space-tight) var(--space-edge-mobile);
  font-size: var(--font-size-small);
  font-weight: var(--font-weight-small);
  color: var(--text);
  text-align: center;
}

.footer a {
  color: var(--text);
  text-decoration: underline;
  transition: color var(--transition-fast);
}

.footer a:hover {
  color: var(--primary);
}

.footer a:active {
  color: var(--primary-active);
}
/* Not applicable: footer text is static, no disabled state. */


/* --- Button pair --- */
/* Stacks full width on phone, sits side by side on desktop. Used for:
   Log In / Sign Up (Home), Add another card / Save deck (Create Deck),
   Mark Reviewed / Mark Not Yet Reviewed (Study Mode),
   Previous card / Next card (Study Mode). */
.button-pair {
  display: flex;
  flex-direction: column;
  gap: var(--space-tight);
}

.button-pair > * {
  width: 100%;
}


/* --------------------------------------------------------------------------
   5. BREAKPOINT
   One breakpoint, mobile-first: min-width: 768px
   -------------------------------------------------------------------------- */

@media (min-width: 768px) {
  /* Page content sits in a centered block with empty space on the sides,
     larger edge padding (about 40 to 70px). */
  .page-container {
    /* .page-container is a flex item of body (column direction), so its
       cross-axis (width) size is "auto" by default. Auto margins on a
       flex item suppress the usual stretch-to-fill behavior, so without
       an explicit width this box would shrink-to-fit its content instead
       of filling up to max-width — on pages whose content width can
       change (e.g. a validation message getting longer), that made the
       whole centered column visibly grow and shrink with the content. */
    width: 100%;
    max-width: var(--content-max-width);
    margin: 0 auto;
    padding-left: var(--space-edge-desktop);
    padding-right: var(--space-edge-desktop);
  }

  .nav-bar,
  .footer {
    padding-left: var(--space-edge-desktop);
    padding-right: var(--space-edge-desktop);
  }

  /* Button pairs sit side by side, each button its natural width. */
  .button-pair {
    flex-direction: row;
    justify-content: center;
    gap: var(--space-standard);
  }

  .button-pair > * {
    width: auto;
  }

  /* Nav bar, deck cards, and the flashcard keep the same single-column
     shape at both sizes; only their edge padding changes, handled above
     and through .page-container. */
}