/* =============================================
   CSS VARIABLES — Light & Dark Theme
   ============================================= */
:root {
  --bg: #ffffff;
  --bg-card: #f4f4f4;
  --bg-input: #ffffff;
  --text: #111111;
  --text-muted: #666666;
  --border: #dddddd;
  --btn-bg: #111111;
  --btn-text: #ffffff;
  --btn-secondary-bg: #eeeeee;
  --btn-secondary-text: #111111;
  --btn-secondary-border: #cccccc;
  --badge-bg: #e0e0e0;
  --badge-text: #111111;
  --slider-thumb: #111111;
  --slider-track: #cccccc;
  --tab-active-bg: #111111;
  --tab-active-text: #ffffff;
  --tab-inactive-bg: transparent;
  --tab-inactive-text: #555555;
  --status-bg: #f0f0f0;
  --header-bg: #111111;
  --header-text: #ffffff;
  --upload-btn-bg: #f4f4f4;
  --upload-btn-border: #cccccc;
  --upload-btn-text: #111111;
  --upload-btn-hover: #e8e8e8;
  --empty-text: #999999;
  --toggle-off: #cccccc;
  --toggle-on: #555555;
  --toggle-knob: #ffffff;
  --divider: #e5e5e5;
  --shadow: 0 2px 8px rgba(0,0,0,0.08);
}

[data-theme="dark"] {
  --bg: #0a0a0a;
  --bg-card: #161616;
  --bg-input: #1e1e1e;
  --text: #e0e0e0;
  --text-muted: #888888;
  --border: #2a2a2a;
  --btn-bg: #2a2a2a;
  --btn-text: #e0e0e0;
  --btn-secondary-bg: #1e1e1e;
  --btn-secondary-text: #cccccc;
  --btn-secondary-border: #2a2a2a;
  --badge-bg: #2a2a2a;
  --badge-text: #cccccc;
  --slider-thumb: #cccccc;
  --slider-track: #333333;
  --tab-active-bg: #2a2a2a;
  --tab-active-text: #e0e0e0;
  --tab-inactive-bg: transparent;
  --tab-inactive-text: #666666;
  --status-bg: #111111;
  --header-bg: #0a0a0a;
  --header-text: #e0e0e0;
  --upload-btn-bg: #1e1e1e;
  --upload-btn-border: #2a2a2a;
  --upload-btn-text: #cccccc;
  --upload-btn-hover: #252525;
  --empty-text: #555555;
  --toggle-off: #333333;
  --toggle-on: #aaaaaa;
  --toggle-knob: #0a0a0a;
  --divider: #1f1f1f;
  --shadow: 0 2px 12px rgba(0,0,0,0.4);
}

/* =============================================
   RESET & BASE
   ============================================= */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition: background 0.3s, color 0.3s;
  font-size: 14px;
}

/* =============================================
   HEADER
   ============================================= */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  height: 56px;
  background: var(--header-bg);
  border-bottom: 1px solid var(--border);
}

.header-left { display: flex; align-items: center; gap: 10px; }
.logo-icon { font-size: 18px; color: var(--header-text); }
.logo-title { font-size: 18px; font-weight: 700; color: var(--header-text); letter-spacing: -0.3px; }
.logo-sub { font-size: 12px; color: #777; border-left: 1px solid #333; padding-left: 10px; margin-left: 2px; }

.theme-toggle {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text);
  width: 36px; height: 36px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 16px;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.2s;
}
.theme-toggle:hover { background: var(--btn-secondary-bg); }

/* =============================================
   MAIN LAYOUT
   ============================================= */
.main { display: flex; gap: 0; height: calc(100vh - 56px); overflow: hidden; }

/* =============================================
   PANELS
   ============================================= */
.panel { background: var(--bg-card); border-right: 1px solid var(--border); }
.panel-title {
  font-size: 13px; font-weight: 600; color: var(--text-muted);
  text-transform: uppercase; letter-spacing: 0.8px; margin-bottom: 20px;
}

.controls-panel {
  width: 290px; min-width: 290px;
  padding: 24px 20px;
  overflow-y: auto;
  display: flex; flex-direction: column; gap: 4px;
}

.preview-panel {
  flex: 1; display: flex; flex-direction: column;
  border-right: none; background: var(--bg);
}

/* =============================================
   CONTROL GROUPS
   ============================================= */
.control-group { margin-bottom: 18px; }

.control-label {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 13px; font-weight: 500; color: var(--text); margin-bottom: 8px;
}
.hint { font-size: 11px; color: var(--text-muted); margin-top: 5px; line-height: 1.4; }
.file-hint { font-size: 11px; color: var(--text-muted); margin-top: 6px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

.badge {
  background: var(--badge-bg); color: var(--badge-text);
  border-radius: 4px; padding: 2px 7px; font-size: 12px; font-weight: 600;
  min-width: 34px; text-align: center;
}

/* DIVIDER */
.divider { height: 1px; background: var(--divider); margin: 8px 0 16px; }

/* =============================================
   TOGGLE SWITCH
   ============================================= */
.toggle-group {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 14px;
}
.toggle-info { display: flex; flex-direction: column; gap: 2px; flex: 1; }
.toggle-label { font-size: 13px; font-weight: 500; color: var(--text); }
.toggle-desc  { font-size: 11px; color: var(--text-muted); }

.toggle-switch { position: relative; display: inline-block; width: 40px; height: 22px; flex-shrink: 0; margin-left: 12px; }
.toggle-switch input { opacity: 0; width: 0; height: 0; }

.toggle-track {
  position: absolute; cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background: var(--toggle-off);
  border-radius: 22px;
  transition: background 0.25s;
}
.toggle-track::before {
  content: "";
  position: absolute;
  width: 16px; height: 16px;
  left: 3px; bottom: 3px;
  background: var(--toggle-knob);
  border-radius: 50%;
  transition: transform 0.25s;
}
.toggle-switch input:checked + .toggle-track { background: var(--toggle-on); }
.toggle-switch input:checked + .toggle-track::before { transform: translateX(18px); }

/* =============================================
   UPLOAD BUTTON
   ============================================= */
.upload-btn {
  display: flex; align-items: center; justify-content: center; gap: 6px;
  width: 100%; padding: 10px;
  background: var(--upload-btn-bg);
  border: 1px dashed var(--upload-btn-border);
  border-radius: 8px;
  color: var(--upload-btn-text);
  cursor: pointer; font-size: 13px; font-weight: 500;
  transition: background 0.2s, border-color 0.2s;
}
.upload-btn:hover { background: var(--upload-btn-hover); border-color: var(--text-muted); }

/* =============================================
   COLOR PICKER
   ============================================= */
.color-row { display: flex; align-items: center; gap: 10px; }

.color-picker {
  width: 44px; height: 36px;
  border: 1px solid var(--border); border-radius: 6px;
  background: var(--bg-input); cursor: pointer; padding: 2px;
}

.color-value {
  font-size: 13px; font-family: monospace; color: var(--text-muted);
  background: var(--bg-input); border: 1px solid var(--border);
  padding: 6px 10px; border-radius: 6px; flex: 1; text-align: center;
}

/* =============================================
   SLIDERS
   ============================================= */
.slider {
  -webkit-appearance: none; appearance: none;
  width: 100%; height: 4px; background: var(--slider-track);
  border-radius: 4px; outline: none; cursor: pointer;
}
.slider::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 16px; height: 16px; border-radius: 50%;
  background: var(--slider-thumb); cursor: pointer;
  border: 2px solid var(--bg-card);
  box-shadow: 0 0 0 1px var(--border);
}
.slider::-moz-range-thumb {
  width: 16px; height: 16px; border-radius: 50%;
  background: var(--slider-thumb); cursor: pointer;
  border: 2px solid var(--bg-card);
}

/* =============================================
   BUTTONS
   ============================================= */
.btn {
  width: 100%; padding: 10px 16px; border-radius: 8px;
  font-size: 13px; font-weight: 600; cursor: pointer;
  transition: opacity 0.2s, background 0.2s;
  margin-bottom: 8px; border: 1px solid transparent;
  letter-spacing: 0.2px;
}
.btn:disabled { opacity: 0.35; cursor: not-allowed; }

.btn-primary { background: var(--btn-bg); color: var(--btn-text); border-color: var(--border); }
.btn-primary:hover:not(:disabled) { opacity: 0.85; }
.btn-secondary { background: var(--btn-secondary-bg); color: var(--btn-secondary-text); border-color: var(--btn-secondary-border); }
.btn-secondary:hover:not(:disabled) { background: var(--upload-btn-hover); }
.btn-download { background: var(--bg-input); color: var(--text); border-color: var(--border); margin-top: 4px; }
.btn-download:hover:not(:disabled) { background: var(--btn-secondary-bg); }

/* =============================================
   PREVIEW PANEL
   ============================================= */
.preview-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 24px 14px;
  border-bottom: 1px solid var(--border);
}

.canvas-tabs { display: flex; gap: 4px; }

.tab {
  background: var(--tab-inactive-bg); color: var(--tab-inactive-text);
  border: 1px solid var(--border); border-radius: 6px;
  padding: 5px 14px; font-size: 12px; font-weight: 500;
  cursor: pointer; transition: background 0.2s, color 0.2s;
}
.tab.active { background: var(--tab-active-bg); color: var(--tab-active-text); border-color: var(--tab-active-bg); }
.tab:hover:not(.active) { background: var(--bg-input); }

/* =============================================
   CANVAS WRAPPER
   ============================================= */
.canvas-wrapper {
  flex: 1; display: flex; align-items: center; justify-content: center;
  overflow: auto; padding: 24px;
  background-image:
    linear-gradient(45deg, #ccc 25%, transparent 25%),
    linear-gradient(-45deg, #ccc 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #ccc 75%),
    linear-gradient(-45deg, transparent 75%, #ccc 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
  background-color: #e8e8e8;
}

[data-theme="dark"] .canvas-wrapper {
  background-image:
    linear-gradient(45deg, #1e1e1e 25%, transparent 25%),
    linear-gradient(-45deg, #1e1e1e 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #1e1e1e 75%),
    linear-gradient(-45deg, transparent 75%, #1e1e1e 75%);
  background-color: #141414;
}

.canvas-wrapper canvas {
  max-width: 100%; max-height: 100%;
  object-fit: contain; border-radius: 4px;
  box-shadow: var(--shadow);
}

.empty-state { text-align: center; color: var(--empty-text); }
.empty-icon { font-size: 56px; margin-bottom: 12px; opacity: 0.3; }
.empty-state p { font-size: 14px; }

/* STATUS BAR */
.status-bar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 24px; background: var(--status-bg);
  border-top: 1px solid var(--border); font-size: 12px; color: var(--text-muted);
}

/* SCROLLBAR */
.controls-panel::-webkit-scrollbar { width: 4px; }
.controls-panel::-webkit-scrollbar-track { background: transparent; }
.controls-panel::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

/* RESPONSIVE */
@media (max-width: 700px) {
  .main { flex-direction: column; height: auto; overflow: auto; }
  .controls-panel { width: 100%; min-width: unset; border-right: none; border-bottom: 1px solid var(--border); }
  .preview-panel { min-height: 60vw; }
}