/* =====================================================
   PaperCalc - main.css
   Layout strategy:
   - Mobile portrait (portrait & ≤600px): 3 vertical rows
     Control panel → Chalkboard → Step log
   - All other cases (landscape / tablet / desktop):
     Top row: Control panel (full width, horizontal)
     Bottom row: Chalkboard (left) | Step log (right) — 2 columns
   ===================================================== */

/* --- CSS variables --- */
:root {
  --color-bg:           #e0f7fa;
  --color-bg-dot:       #b2ebf2;
  --color-primary:      #00796b;
  --color-primary-dark: #004d40;
  --color-accent:       #0288d1;
  --color-panel-bg:     #ffffff;
  --color-panel-border: #4fc3f7;
  --color-panel-shadow: #b3e5fc;
  --color-input-bg:     #f0f4f8;
  --color-input-border: #90caf9;
  --color-btn-start-bg: #81c784;
  --color-btn-start-sh: #388e3c;
  --color-btn-stop-bg:  #ef5350;
  --color-btn-stop-sh:  #c62828;
  --color-btn-bg:       #ffb74d;
  --color-btn-shadow:   #e65100;
  --color-btn-dis-bg:   #e0e0e0;
  --color-btn-dis-fg:   #a0a0a0;
  --color-log-active-bg:#e3f2fd;
  --color-log-active-fg:#0d47a1;
  --color-log-active-bd:#1976d2;
  --color-text:         #333;
  --color-footer:       #666;
  --color-error:        #f44336;

  --gap-sm:    6px;
  --gap-md:    10px;
  --gap-lg:    16px;

  --radius-sm: 4px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-pill: 50px;

  --font-ui: "Nunito", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --font-ui-2: Tahoma, Arial, monospace;
  --font-log: Helvetica, Calibri, "Palatino Linotype", "Book Antiqua", Palatino, serif;

  --touch-min: 44px;
}

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

/* =====================================================
   Body: fills the screen using a vertical flex layout
   ===================================================== */
body {
  margin: 0;
  padding: 6px 8px;
  font-size: 1.05rem;
  font-family: var(--font-ui);
  color: var(--color-text);
  background-color: var(--color-bg);
  background-image: radial-gradient(var(--color-bg-dot) 10%, transparent 10%);
  background-size: 20px 20px;
  display: flex;
  flex-direction: column;
  height: 100dvh;
  overflow: hidden;
}

/* =====================================================
   Header
   ===================================================== */
header {
  flex: 0 0 auto;
  font-size: 1.1rem;
  font-weight: bold;
  color: var(--color-primary);
  text-shadow: 1px 1px 0 #fff;
  text-align: center;
  padding-bottom: 4px;
  margin-bottom: 4px;
  border-bottom: 4px dotted var(--color-primary);
}

/* =====================================================
   Footer
   ===================================================== */
footer {
  flex: 0 0 auto;
  font-size: 0.78rem;
  text-align: center;
  color: var(--color-footer);
  margin-top: 4px;
}

/* =====================================================
   Main container
   [Default = landscape / tablet / desktop]
   Top row: Control panel (full width)
   Bottom row: Chalkboard (left) | Step log (right)
   ===================================================== */
#my-container {
  flex: 1 1 0;
  min-height: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: auto 1fr;
  gap: var(--gap-md);
}

/* --- Control panel: full-width top row, horizontal layout --- */
#my-control-panel {
  grid-column: 1 / 3;
  grid-row: 1 / 2;
  background-color: var(--color-panel-bg);
  border: 3px solid var(--color-panel-border);
  border-radius: var(--radius-lg);
  box-shadow: 0 3px 0 var(--color-panel-shadow);
  padding: 8px 12px;
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

/* --- Chalkboard: bottom-left --- */
#my-canvas-space {
  grid-column: 1 / 2;
  grid-row: 2 / 3;
  background-color: var(--color-primary-dark);
  border-radius: var(--radius-md);
  box-shadow: 0 5px 15px rgba(0,0,0,0.3);
  padding: 4% 3% 6%;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: auto;
  min-height: 0;
}

/* --- Step log wrapper: bottom-right --- */
#my-container > div:last-child {
  grid-column: 2 / 3;
  grid-row: 2 / 3;
  position: relative;
  min-height: 0;
}

/* =====================================================
   Canvas element
   ===================================================== */
#my-canvas {
  max-width: 100%;
  max-height: 100%;
  filter: invert(100%);
  mix-blend-mode: screen;
  opacity: 0.95;
  touch-action: none;
  -ms-touch-action: none;
}

/* =====================================================
   Step log panel
   ===================================================== */
#my-textarea {
  position: absolute;
  inset: 0;
  border-radius: var(--radius-sm);
  background-color: var(--color-panel-bg);
  border: 1px solid #ccc;
  border-top: 6px solid var(--color-panel-border);
  overflow-y: auto;
  padding: 8px 12px;
  font-size: 0.95rem;
  font-family: var(--font-log);
  box-shadow: 0 4px 8px rgba(0,0,0,0.08);
  display: flex;
  flex-direction: column-reverse;
  line-height: 1.5;
  scroll-behavior: smooth;
}

.log-item {
  border-bottom: 1px solid #e0e0e0;
  padding: 6px 0;
  color: #444;
  transition: all 0.3s ease;
}

.log-item.active {
  background-color: var(--color-log-active-bg);
  color: var(--color-log-active-fg);
  font-weight: bold;
  border-left: 6px solid var(--color-log-active-bd);
  padding-left: 10px;
  border-radius: 2px;
  transform: scale(1.01);
}

/* =====================================================
   Form controls
   ===================================================== */
select,
input[type="text"],
input[type="number"] {
  color: var(--color-text);
  background-color: var(--color-input-bg);
  border-radius: 10px;
  padding: 6px 10px;
  border: 2px solid var(--color-input-border);
  font-size: 0.95rem;
  font-family: var(--font-ui-2);
  outline: none;
  transition: border-color 0.2s, background-color 0.2s;
  min-height: var(--touch-min);
}

input[type="text"],
input[type="number"] { text-align: right; }

input[type="range"] {
  vertical-align: middle;
  margin: 0 4px;
}

select:focus, input:focus {
  border-color: var(--color-accent);
  background-color: #fff;
  color: #000;
}

select:focus-visible, input:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 2px;
}

select:disabled,
input[type="text"]:disabled,
input[type="number"]:disabled {
  background-color: #ccc;
  cursor: not-allowed;
}

/* =====================================================
   Buttons — shared styles
   ===================================================== */
button {
  cursor: pointer;
  font-weight: bold;
  font-size: 0.95rem;
  font-family: var(--font-ui);
  border-radius: var(--radius-pill);
  padding: 8px 14px;
  border: none;
  background-color: var(--color-btn-bg);
  color: #fff;
  box-shadow: 0 4px 0 var(--color-btn-shadow);
  transition: background-color 0.1s, transform 0.1s, box-shadow 0.1s;
  min-height: var(--touch-min);
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  white-space: nowrap;
}

button:hover:not(:disabled) {
  background-color: #ff9800;
  transform: translateY(2px);
  box-shadow: 0 2px 0 var(--color-btn-shadow);
}

button:active:not(:disabled) {
  transform: translateY(4px);
  box-shadow: none;
}

button:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 2px;
}

button:disabled {
  background-color: var(--color-btn-dis-bg) !important;
  color: var(--color-btn-dis-fg) !important;
  box-shadow: none !important;
  transform: translateY(4px) !important;
  cursor: not-allowed !important;
  opacity: 1 !important;
}

#my-start-button {
  background-color: var(--color-btn-start-bg);
  box-shadow: 0 4px 0 var(--color-btn-start-sh);
}
#my-start-button:hover:not(:disabled) { background-color: #66bb6a; }

#my-stop-button {
  background-color: var(--color-btn-stop-bg);
  box-shadow: 0 4px 0 var(--color-btn-stop-sh);
}
#my-stop-button:hover:not(:disabled) { background-color: #e53935; }

/* =====================================================
   Button group
   ===================================================== */
.button-group {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 6px;
}

/* =====================================================
   Utilities
   ===================================================== */
.no-wrap { white-space: nowrap; }
.hidden  { display: none !important; }
.center  { text-align: center; }

#speed-label {
  display: inline-block;
  width: 5rem;
  text-align: left;
  margin-left: 4px;
  vertical-align: middle;
}

/* =====================================================
   Error display
   ===================================================== */
.input-error {
  background-color: #ffcdd2 !important;
  border: 2px solid var(--color-error) !important;
}

#input-error-message {
  color: var(--color-error);
  font-size: 0.88em;
  font-weight: bold;
  min-height: 1.2em;
}

/* =====================================================
   Mobile portrait (portrait & max-width 600px)
   3 vertical rows: Control panel → Chalkboard → Step log
   ===================================================== */
@media (max-width: 600px) and (orientation: portrait) {
  body {
    padding: 4px 5px;
    font-size: 0.97rem;
  }

  /* Container: switch to vertical flex column */
  #my-container {
    display: flex;
    flex-direction: column;
    flex: 1 1 0;
    gap: 5px;
    min-height: 0;
    overflow: hidden;
  }

  /* Control panel: shrinks to fit its content height */
  #my-control-panel {
    flex: 0 0 auto;
    grid-column: unset;
    grid-row: unset;
    padding: 6px 8px;
    gap: 5px;
  }

  /* Chalkboard: takes up the larger share of remaining height */
  #my-canvas-space {
    flex: 3 1 0;
    grid-column: unset;
    grid-row: unset;
    width: 100%;
    aspect-ratio: unset;
    min-height: 0;
    padding: 3% 3% 5%;
  }

  /* Step log wrapper: takes up the smaller share of remaining height */
  #my-container > div:last-child {
    flex: 2 1 0;
    grid-column: unset;
    grid-row: unset;
    min-height: 0;
    position: relative;
  }

  select,
  input[type="text"],
  input[type="number"] {
    font-size: 0.92rem;
  }
}

/* =====================================================
   Extra-small phones (≤360px, portrait)
   ===================================================== */
@media (max-width: 360px) and (orientation: portrait) {
  body {
    font-size: 0.88rem;
    padding: 3px 4px;
  }

  header { font-size: 0.9rem; }

  #my-control-panel {
    padding: 5px 6px;
    gap: 4px;
  }

  select,
  input[type="text"],
  input[type="number"] {
    font-size: 0.82rem;
  }

  button {
    font-size: 0.82rem;
    padding: 6px 10px;
  }

  #my-canvas-space {
    padding: 2% 2% 4%;
  }
}

/* =====================================================
   Dark mode
   ===================================================== */
/*
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg:           #102027;
    --color-bg-dot:       #1c3a47;
    --color-primary:      #4db6ac;
    --color-panel-bg:     #1e2d38;
    --color-panel-border: #0288d1;
    --color-panel-shadow: #01579b;
    --color-input-bg:     #263545;
    --color-input-border: #0277bd;
    --color-text:         #eceff1;
    --color-footer:       #90a4ae;
    --color-log-active-bg:#0d2137;
  }

  #my-textarea {
    background-color: var(--color-panel-bg);
    border-color: #455a64;
    border-top-color: var(--color-panel-border);
    color: var(--color-text);
  }

  .log-item {
    color: #b0bec5;
    border-bottom-color: #37474f;
  }

  select:disabled,
  input[type="text"]:disabled,
  input[type="number"]:disabled {
    background-color: #37474f;
    color: #607d8b;
  }
}*/

/* =====================================================
   Reduced motion
   ===================================================== */
@media (prefers-reduced-motion: reduce) {
  * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
  }
}