/*
 * SPDX-License-Identifier: Apache-2.0
 * Copyright 2026 CLSOFTLAB (씨엘소프트랩), Dr. Lee Il-guk (이일국)
 *
 * style.css — the canvas is always night; the UI panel respects light/dark and
 * stays high-contrast over the sky. Responsive down to 360px.
 */

:root {
  --panel-bg: rgba(10, 14, 26, 0.82);
  --panel-border: rgba(150, 180, 255, 0.16);
  --text: #eef2ff;
  --text-dim: #a9b4d0;
  --accent: #ffcf7a;      /* amber */
  --accent-cool: #9fc7ff; /* spark blue */
  --focus: #ffe08a;
  --btn-bg: rgba(40, 52, 84, 0.7);
  --btn-bg-hover: rgba(64, 82, 128, 0.9);
  --track: rgba(255, 255, 255, 0.14);
  --radius: 12px;
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.45);
}

:root[data-theme="light"] {
  /* The sky stays dark; only the surrounding chrome lightens for readability. */
  --panel-bg: rgba(244, 247, 255, 0.9);
  --panel-border: rgba(30, 50, 110, 0.18);
  --text: #10182e;
  --text-dim: #465274;
  --focus: #b25e00;
  --btn-bg: rgba(210, 222, 250, 0.9);
  --btn-bg-hover: rgba(190, 206, 245, 1);
  --track: rgba(20, 30, 60, 0.16);
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --panel-bg: rgba(244, 247, 255, 0.9);
    --panel-border: rgba(30, 50, 110, 0.18);
    --text: #10182e;
    --text-dim: #465274;
    --focus: #b25e00;
    --btn-bg: rgba(210, 222, 250, 0.9);
    --btn-bg-hover: rgba(190, 206, 245, 1);
    --track: rgba(20, 30, 60, 0.16);
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Malgun Gothic", sans-serif;
  color: var(--text);
  background: #04060f;
}

#sky {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
}

/* --- Title bar --- */
.titlebar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 10px 14px;
  padding-block: 10px;
  pointer-events: none;
  z-index: 5;
}
.titlebar h1 {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: 0.3px;
  color: #f4f7ff;
  text-shadow: 0 1px 8px rgba(0, 0, 0, 0.85);
  pointer-events: none;
}
.titlebar .glyph { color: var(--accent); }
.titlebar .ko { color: var(--text-dim); font-weight: 400; font-size: 0.85em; }
.titlebar .ghost { pointer-events: auto; }

/* --- HUD (fps / count / sync) --- */
.hud {
  position: fixed;
  top: 46px;
  left: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  z-index: 5;
  pointer-events: none;
}
.hud-item {
  font-variant-numeric: tabular-nums;
  font-size: 0.72rem;
  padding: 3px 8px;
  border-radius: 999px;
  background: rgba(8, 12, 24, 0.6);
  border: 1px solid rgba(160, 190, 255, 0.18);
  color: #dbe4ff;
  text-shadow: 0 1px 4px rgba(0, 0, 0, 0.8);
}

/* --- Control panel --- */
.panel {
  position: fixed;
  top: 82px;
  right: 14px;
  width: 300px;
  max-width: calc(100vw - 28px);
  max-height: calc(100vh - 150px);
  overflow-y: auto;
  padding: 14px 16px;
  padding-block: 14px;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 6;
}
.panel[hidden] { display: none !important; }

.panel .row.primary {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 8px;
}

.panel fieldset {
  border: 1px solid var(--panel-border);
  border-radius: 10px;
  margin: 10px 0 0;
  padding: 8px 12px 12px;
}
.panel legend {
  font-size: 0.74rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  padding: 0 6px;
}

.panel label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 8px;
  margin-top: 10px;
  font-size: 0.82rem;
  color: var(--text);
}
.panel fieldset > label:first-of-type { margin-top: 2px; }
.panel output {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  font-size: 0.8rem;
}

input[type="range"] {
  width: 100%;
  margin: 6px 0 2px;
  accent-color: var(--accent);
  height: 22px;
  background: transparent;
}
select {
  width: 100%;
  margin-top: 6px;
  padding: 6px 8px;
  border-radius: 8px;
  background: var(--btn-bg);
  color: var(--text);
  border: 1px solid var(--panel-border);
  font-size: 0.85rem;
}

button {
  font: inherit;
  cursor: pointer;
  border-radius: 9px;
  border: 1px solid var(--panel-border);
  background: var(--btn-bg);
  color: var(--text);
  padding: 8px 12px;
  font-size: 0.83rem;
  transition: background 0.15s ease, transform 0.05s ease;
}
button:hover { background: var(--btn-bg-hover); }
button:active { transform: translateY(1px); }
.primary-btn {
  background: linear-gradient(180deg, rgba(255, 207, 122, 0.95), rgba(255, 176, 74, 0.95));
  color: #241300;
  border-color: rgba(255, 220, 150, 0.5);
  font-weight: 650;
  flex: 1 1 auto;
}
.primary-btn[aria-pressed="false"] {
  background: var(--btn-bg);
  color: var(--text);
  font-weight: 600;
}
.ghost { background: var(--btn-bg); }

.hint {
  margin: 8px 0 0;
  font-size: 0.76rem;
  color: var(--text-dim);
  min-height: 1em;
}
.about { margin-top: 12px; }
.about summary {
  cursor: pointer;
  font-size: 0.8rem;
  color: var(--text-dim);
}
.about p {
  margin: 8px 0 0;
  font-size: 0.78rem;
  line-height: 1.5;
  color: var(--text-dim);
}

/* --- Footer --- */
.footer {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 14px;
  justify-content: center;
  align-items: center;
  padding: 7px 12px;
  padding-block: 7px;
  font-size: 0.72rem;
  color: #b9c4e4;
  background: linear-gradient(0deg, rgba(4, 6, 15, 0.85), rgba(4, 6, 15, 0));
  text-shadow: 0 1px 4px rgba(0, 0, 0, 0.9);
  z-index: 4;
  pointer-events: none;
}
.footer a { color: var(--accent-cool); pointer-events: auto; }

/* --- Accessibility helpers --- */
.skip-link {
  position: fixed;
  left: 8px;
  top: -60px;
  z-index: 20;
  background: var(--panel-bg);
  color: var(--text);
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid var(--panel-border);
  transition: top 0.15s ease;
}
.skip-link:focus { top: 8px; }

.sr-note {
  margin: 4px 0 0;
  font-size: 0.72rem;
  color: var(--text-dim);
  line-height: 1.4;
}

a, button, input, select, summary { }
:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 6px;
}

/* --- Responsive: phones down to 360px --- */
@media (max-width: 640px) {
  .panel {
    top: auto;
    bottom: 34px;
    left: 8px;
    right: 8px;
    width: auto;
    max-height: 54vh;
  }
  .hud { top: 44px; }
  .titlebar h1 { font-size: 0.95rem; }
}
@media (max-width: 380px) {
  .panel { padding: 10px 12px; }
  .titlebar .ko { display: none; }
}

/* Respect reduced-motion for UI transitions (the sim has its own motion control) */
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}