:root {
  /* Light Theme Design Tokens (Default) */
  --paper: #FAFAF6;
  --surface: #F3F4F6;
  --surface-container: rgba(255, 255, 255, 0.7);
  --surface-container-low: #FFFFFF;
  --surface-container-lowest: #F8FAFC;
  --surface-variant: #E2E8F0;
  
  --ink: #1E293B;
  --ink-soft: #64748B;
  
  --navy: #2563EB; /* Bright Blue for Light Mode */
  --navy-deep: #1D4ED8;
  --navy-glow: rgba(37, 99, 235, 0.2);
  
  --outline-variant: #E2E8F0;
  --stamp: #E11D48;
  --error: #EF4444;
  --error-container: rgba(239, 68, 68, 0.1);
  
  --card-border: rgba(0, 0, 0, 0.05);
  --shadow-card: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --shadow-card-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.05), 0 10px 10px -5px rgba(0, 0, 0, 0.02), 0 0 15px var(--navy-glow);
  
  --radius: 12px;
  --radius-sm: 8px;
}

[data-theme="dark"] {
  /* Dark Theme Design Tokens */
  --paper: #0B1120;
  --surface: #131B2C;
  --surface-container: rgba(30, 41, 59, 0.7);
  --surface-container-low: #1E293B;
  --surface-container-lowest: #0F172A;
  --surface-variant: #334155;
  
  --ink: #F8FAFC;
  --ink-soft: #94A3B8;
  
  --navy: #3B82F6;
  --navy-deep: #2563EB;
  --navy-glow: rgba(59, 130, 246, 0.4);
  
  --outline-variant: #334155;
  --stamp: #F43F5E;
  --error: #EF4444;
  --error-container: rgba(239, 68, 68, 0.15);
  
  --card-border: rgba(255, 255, 255, 0.08);
  --shadow-card: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-card-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.6), 0 10px 10px -5px rgba(0, 0, 0, 0.4), 0 0 15px var(--navy-glow);
}

* {
  box-sizing: border-box;
  transition: background-color 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
              border-color 0.3s cubic-bezier(0.4, 0, 0.2, 1),
              color 0.3s cubic-bezier(0.4, 0, 0.2, 1),
              box-shadow 0.3s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.material-symbols-outlined {
  font-variation-settings: 'FILL' 0, 'wght' 400, 'GRAD' 0, 'opsz' 24;
  font-size: 20px;
  line-height: 1;
  vertical-align: middle;
}

body {
  margin: 0;
  background: var(--paper);
  background-image: radial-gradient(circle at top right, rgba(59, 130, 246, 0.08), transparent 500px),
                    radial-gradient(circle at bottom left, rgba(139, 92, 246, 0.08), transparent 500px);
  background-attachment: fixed;
  color: var(--ink);
  font-family: 'Inter', sans-serif;
  -webkit-font-smoothing: antialiased;
  display: flex;
  min-height: 100vh;
}

/* Glassmorphism for Topbar */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--outline-variant);
  background: var(--surface-container);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  position: sticky;
  top: 0;
  z-index: 20;
}

@media (min-width:900px) {
  .topbar {
    display: none;
  }
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand .mark {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--navy), #8B5CF6);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-family: 'Space Grotesk', sans-serif;
  font-size: 14px;
  font-weight: 700;
  box-shadow: 0 4px 12px var(--navy-glow);
}

.brand h1 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 18px;
  font-weight: 700;
  margin: 0;
  letter-spacing: -0.01em;
  background: linear-gradient(to right, var(--ink), var(--ink-soft));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand .sub {
  font-size: 10px;
  color: var(--ink-soft);
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: 0.03em;
}

/* Glassmorphism for Sidenav */
.sidenav {
  display: none;
}

@media (min-width:900px) {
  .sidenav {
    display: flex;
    flex-direction: column;
    width: 90px;
    flex-shrink: 0;
    background: var(--surface-container);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border-right: 1px solid var(--outline-variant);
    padding: 24px 0;
    position: sticky;
    top: 0;
    height: 100vh;
    z-index: 50;
  }

  .sidenav .brandmark {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    margin-bottom: 32px;
  }

  .sidenav .brandmark .mark {
    width: 42px;
    height: 42px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--navy), #8B5CF6);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 700;
    font-size: 16px;
    box-shadow: 0 4px 15px var(--navy-glow);
  }

  .sidenav .tab {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    padding: 14px 6px;
    margin: 4px 12px;
    border-radius: var(--radius-sm);
    color: var(--ink-soft);
    cursor: pointer;
    border-left: 3px solid transparent;
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    letter-spacing: 0.05em;
    text-align: center;
    text-transform: uppercase;
  }

  .sidenav .tab .material-symbols-outlined {
    font-size: 24px;
  }

  .sidenav .tab:hover {
    background: rgba(100, 100, 100, 0.05);
    color: var(--ink);
    transform: translateY(-2px);
  }

  .sidenav .tab.active {
    background: rgba(59, 130, 246, 0.15);
    color: var(--navy);
    border-left-color: var(--navy);
    margin-left: 0;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    box-shadow: inset 2px 0 10px rgba(59,130,246,0.1);
  }
}

/* Bottom Nav Mobile */
.bottomnav {
  display: flex;
  justify-content: space-around;
  align-items: center;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 70px;
  background: var(--surface-container);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-top: 1px solid var(--outline-variant);
  z-index: 50;
  padding-bottom: env(safe-area-inset-bottom);
}

@media (min-width:900px) {
  .bottomnav {
    display: none;
  }
}

.bottomnav .tab {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: var(--ink-soft);
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  cursor: pointer;
  padding: 8px;
}

.bottomnav .tab.active {
  color: var(--navy);
}

.bottomnav .tab .material-symbols-outlined {
  font-size: 24px;
}

/* Main Content */
main {
  flex: 1;
  max-width: 1000px;
  margin: 0 auto;
  padding: 32px 24px 100px;
  width: 100%;
}

@media (min-width:900px) {
  main {
    padding: 48px 60px 80px;
  }
}

.panel {
  display: none;
  animation: fadeIn 0.4s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.panel.active {
  display: block;
}

.panel-header {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 24px;
}

.panel-title h2 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 32px;
  font-weight: 700;
  margin: 0 0 8px;
  letter-spacing: -0.02em;
}

.panel-title p {
  font-size: 14px;
  color: var(--ink-soft);
  margin: 0;
  max-width: 560px;
  line-height: 1.5;
}

.privacy-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(100, 100, 100, 0.05);
  border: 1px solid var(--card-border);
  color: var(--ink-soft);
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.03em;
  padding: 4px 10px;
  border-radius: 20px;
  margin-top: 12px;
}

.privacy-chip .material-symbols-outlined {
  font-size: 14px;
  color: #10B981;
}

/* Drop zone */
.drop {
  border: 2px dashed var(--outline-variant);
  border-radius: 16px;
  padding: 48px 24px;
  text-align: center;
  background: var(--surface-container-low);
  cursor: pointer;
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 2px 10px rgba(0,0,0,0.02);
}

.drop::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: linear-gradient(45deg, rgba(59, 130, 246, 0.05), rgba(139, 92, 246, 0.05));
  opacity: 0;
  transition: opacity 0.3s;
  z-index: 0;
}

.drop:hover::before,
.drop.drag::before {
  opacity: 1;
}

.drop.drag {
  border-color: var(--navy);
  animation: pulseBorder 1.5s infinite;
}

@keyframes pulseBorder {
    0% { border-color: rgba(59,130,246,0.5); box-shadow: inset 0 0 0 0 rgba(59,130,246,0.1); }
    50% { border-color: rgba(59,130,246,1); box-shadow: inset 0 0 0 5px rgba(59,130,246,0); }
    100% { border-color: rgba(59,130,246,0.5); box-shadow: inset 0 0 0 0 rgba(59,130,246,0); }
}

.drop * {
  position: relative;
  z-index: 1;
}

.drop .icon-circle {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--surface-container-lowest);
  border: 1px solid var(--card-border);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  color: var(--ink-soft);
  box-shadow: var(--shadow-card);
}

.drop:hover .icon-circle, .drop.drag .icon-circle {
  background: linear-gradient(135deg, var(--navy), #8B5CF6);
  color: #fff;
  transform: scale(1.1) translateY(-4px);
  box-shadow: 0 10px 20px var(--navy-glow);
  border-color: transparent;
}

.drop h3 {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 600;
  font-size: 18px;
  margin: 0 0 6px;
}

.drop p {
  font-size: 14px;
  color: var(--ink-soft);
  margin: 0;
}

input[type=file] {
  display: none;
}

/* Toolbar */
.toolrow {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin: 24px 0 8px;
  align-items: center;
  background: var(--surface-container-lowest);
  padding: 16px;
  border-radius: var(--radius);
  border: 1px solid var(--card-border);
  box-shadow: var(--shadow-card);
}

.btn-group {
  display: flex;
  background: var(--surface-container-low);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.btn-group button {
  border: none;
  border-right: 1px solid var(--card-border);
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  box-shadow: none;
}

.btn-group button:last-child {
  border-right: none;
}

.btn-group button:hover {
  background: rgba(100,100,100,0.05);
  transform: none;
}

button {
  font-family: 'Inter', sans-serif;
  font-weight: 600;
  font-size: 14px;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  background: var(--navy);
  color: #fff;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.2);
}

button:hover {
  background: var(--navy-deep);
  transform: translateY(-2px);
  box-shadow: 0 8px 15px var(--navy-glow);
}

button:active {
  transform: translateY(1px);
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

button.ghost {
  background: rgba(100,100,100,0.05);
  color: var(--ink);
  border: 1px solid var(--card-border);
  box-shadow: none;
}

button.ghost:hover {
  background: rgba(100,100,100,0.1);
  border-color: var(--outline-variant);
}

button.danger {
  background: var(--error-container);
  color: var(--error);
  border: 1px solid transparent;
}

button.danger:hover {
  background: var(--error);
  color: #fff;
  box-shadow: 0 8px 15px rgba(239, 68, 68, 0.3);
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
  filter: grayscale(1);
}

/* Card grid */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 24px;
  margin-top: 24px;
}

.card {
  background: var(--surface-container-lowest);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 10px 10px 12px;
  box-shadow: var(--shadow-card);
  cursor: grab;
  position: relative;
}

.card:hover {
  transform: translateY(-6px) scale(1.02);
  border-color: var(--navy-glow);
  box-shadow: var(--shadow-card-hover);
  z-index: 2;
}

.card:active {
  cursor: grabbing;
  transform: scale(0.98);
}

.card.dragging {
  opacity: 0.4;
  transform: scale(0.95);
}

.card.over {
  outline: 2px solid var(--navy);
}

.card canvas,
.card img {
  width: 100%;
  display: block;
  border-radius: var(--radius-sm);
  border: 1px solid var(--card-border);
  background: var(--surface-container-low);
}

.badge {
  position: absolute;
  top: -9px;
  right: -9px;
  left: auto;
  background: var(--stamp);
  color: #fff;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  font-weight: 500;
  width: 23px;
  height: 23px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
  border: 2px solid var(--surface-container-lowest);
}

.card .fname {
  font-size: 10.5px;
  color: var(--ink-soft);
  margin-top: 7px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  font-family: 'JetBrains Mono', monospace;
}

.card .remove {
  position: absolute;
  top: -9px;
  left: -9px;
  right: auto;
  background: var(--surface-container-lowest);
  color: var(--error);
  border: 1px solid var(--card-border);
  width: 22px;
  height: 22px;
  border-radius: 50%;
  font-size: 13px;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.card .remove:hover {
  background: var(--error-container);
}

.empty-hint {
  font-size: 12px;
  color: var(--ink-soft);
  text-align: center;
  padding: 30px;
  font-family: 'JetBrains Mono', monospace;
}

.status {
  margin-top: 16px;
  font-size: 12px;
  color: var(--ink-soft);
  font-family: 'JetBrains Mono', monospace;
  min-height: 18px;
  letter-spacing: 0.02em;
}

.status.ok {
  color: #10B981;
}

.status.err {
  color: var(--stamp);
}

.field-row {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
  margin: 14px 0;
}

label.small {
  font-size: 12px;
  color: var(--ink-soft);
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: 0.02em;
}

input[type=number],
select {
  font-family: 'Inter', sans-serif;
  font-size: 13px;
  padding: 8px 10px;
  border: 1px solid var(--outline-variant);
  border-radius: var(--radius-sm);
  background: var(--surface-container-lowest);
  color: var(--ink);
  border-bottom: 2px solid var(--navy);
  transition: border-color 0.2s;
}

input[type=number]:focus,
select:focus {
  outline: none;
  border-bottom-color: var(--navy-deep);
  background: var(--surface-container-low);
}

footer {
  text-align: center;
  padding: 24px;
  font-size: 12px;
  color: var(--ink-soft);
  font-family: 'JetBrains Mono', monospace;
  border-top: 1px solid var(--outline-variant);
  max-width: 1200px;
  margin: 0 auto;
}

/* Theme Toggle Button */
.theme-toggle {
  background: transparent;
  border: none;
  color: var(--ink-soft);
  cursor: pointer;
  padding: 8px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  box-shadow: none;
}

.theme-toggle:hover {
  background: rgba(100,100,100,0.1);
  color: var(--ink);
  transform: rotate(15deg);
}

[data-theme="dark"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: none; }
:root:not([data-theme]) .icon-sun { display: none; } /* Default to dark icon if light theme active natively */

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .icon-moon { display: none; }
  :root:not([data-theme="light"]) .icon-sun { display: block; }
}

/* Add Text & E-Sign */
.overlay-text {
  position: absolute;
  cursor: move;
  user-select: none;
  padding: 4px 8px;
  border: 1px dashed transparent;
  white-space: pre;
}
.overlay-text:hover {
  border-color: var(--navy);
  background: var(--navy-glow);
}
.overlay-text .remove-btn, .overlay-img .remove-btn {
  position: absolute;
  top: -10px;
  right: -10px;
  background: var(--stamp);
  color: #fff;
  border: none;
  border-radius: 50%;
  width: 20px;
  height: 20px;
  font-size: 12px;
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 10;
}
.overlay-text:hover .remove-btn, .overlay-img:hover .remove-btn {
  display: flex;
}
.overlay-img {
  position: absolute;
  cursor: move;
  border: 1px dashed transparent;
}
.overlay-img:hover {
  border-color: var(--navy);
}
.overlay-img img {
  width: 100%;
  height: 100%;
  pointer-events: none;
}
.resize-handle {
  position: absolute;
  right: -5px;
  bottom: -5px;
  width: 12px;
  height: 12px;
  background: var(--navy);
  border-radius: 50%;
  cursor: se-resize;
  display: none;
}
.overlay-img:hover .resize-handle {
  display: block;
}
.canvas-wrapper {
  position: relative;
  display: inline-block;
  box-shadow: var(--shadow-card);
  margin: 10px;
  background: #fff;
  border-radius: var(--radius-sm);
}
.canvas-wrapper canvas {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
}
#signature-pad-container {
  background: var(--surface-container-lowest);
  border: 2px dashed var(--outline-variant);
  border-radius: var(--radius);
  margin-bottom: 16px;
  overflow: hidden;
  touch-action: none;
}
#signature-pad {
  width: 100%;
  height: 200px;
  cursor: crosshair;
}