body {
    margin: 0;
    overflow: hidden;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #1a202c 0%, #2d3748 100%);
    transition: background 0.3s ease;
}

body.dark-mode {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
}

body.light-mode {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

#container {
    width: 100vw;
    height: 100vh;
}

/* View Controls (Right Side) */
#view-controls {
    position: fixed;
    top: 20px;
    right: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 100;
}

.view-control-btn {
    width: 50px;
    height: 50px;
    background: rgba(255, 255, 255, 0.95);
    border: none;
    border-radius: 10px;
    font-size: 24px;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    margin: 0;
}

.view-control-btn:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.3);
}

.view-control-btn:active {
    transform: scale(0.95);
}

body.dark-mode .view-control-btn {
    background: rgba(30, 41, 59, 0.95);
    border: 1px solid rgba(148, 163, 184, 0.2);
}

#controls {
    position: absolute;
    top: 20px;
    left: 20px;
    background: rgba(255, 255, 255, 0.95);
    padding: 25px;
    border-radius: 12px;
    max-width: 420px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    z-index: 100;
    max-height: 90vh;
    overflow-y: auto;
    transition: background 0.3s ease, color 0.3s ease;
}

body.dark-mode #controls {
    background: rgba(30, 41, 59, 0.95);
    color: #f1f5f9;
    border: 1px solid rgba(148, 163, 184, 0.2);
}

h2 {
    margin: 0 0 20px 0;
    color: #2d3748;
    font-size: 24px;
}

body.dark-mode h2 {
    color: #f1f5f9;
}

/* Mode Tabs */
.mode-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}
.tab-button {
    flex: 1;
    padding: 10px;
    background: #e2e8f0;
    color: #4a5568;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    margin-top: 0;
}

body.dark-mode .tab-button {
    background: #334155;
    color: #e2e8f0;
}

.tab-button:hover {
    background: #cbd5e0;
    transform: none;
}

body.dark-mode .tab-button:hover {
    background: #475569;
}

.tab-button.active {
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    color: white;
    box-shadow: 0 2px 8px rgba(59, 130, 246, 0.4);
}

/* Mode Content */
.mode-content {
    display: none;
}
.mode-content.active {
    display: block;
}

.input-group {
    margin: 15px 0;
    padding: 15px;
    background: #f7fafc;
    border-radius: 8px;
    border-left: 4px solid #3b82f6;
}

body.dark-mode .input-group {
    background: rgba(30, 41, 59, 0.3);
    border-left: 4px solid #60a5fa;
}

.slab-mode {
    border-left: 4px solid #805ad5;
}
label {
    display: block;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 8px;
    font-size: 14px;
}

body.dark-mode label {
    color: #cbd5e0;
}

input, select {
    width: 100%;
    padding: 10px;
    border: 2px solid #e2e8f0;
    border-radius: 6px;
    font-size: 14px;
    box-sizing: border-box;
    transition: border-color 0.3s;
    background: white;
    color: #2d3748;
}

body.dark-mode input,
body.dark-mode select {
    background: rgba(15, 23, 42, 0.6);
    border-color: rgba(71, 85, 105, 0.4);
    color: #f1f5f9;
}

input:focus, select:focus {
    outline: none;
    border-color: #3b82f6;
}

body.dark-mode input:focus,
body.dark-mode select:focus {
    background: rgba(15, 23, 42, 0.8);
    border-color: #60a5fa;
}

.inline-inputs {
    display: flex;
    gap: 10px;
    align-items: center;
}
.inline-inputs select {
    width: 80px;
}
.inline-inputs input {
    flex: 1;
}
.slab-container {
    display: none;
}
.slab-container.active {
    display: block;
}
.slab-inputs {
    display: flex;
    gap: 10px;
    align-items: center;
    margin-top: 8px;
}
.slab-inputs input {
    flex: 1;
}
.slab-label {
    font-size: 12px;
    color: #718096;
    margin: 5px 0;
}

body.dark-mode .slab-label {
    color: #a0aec0;
}

.checkbox-container {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 10px;
}
.checkbox-container input[type="checkbox"] {
    width: auto;
    margin: 0;
}
button {
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    margin-top: 15px;
    transition: transform 0.2s;
    position: relative;
}
button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.4);
}
button:active {
    transform: translateY(0);
}
button.processing {
    pointer-events: none;
    opacity: 0.8;
}
button.processing::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    top: 50%;
    right: 15px;
    margin-top: -8px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.6s linear infinite;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}
.clear-btn {
    background: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
    margin-top: 10px;
}
.info-text {
    font-size: 12px;
    color: #718096;
    margin-top: 5px;
    font-style: italic;
}

body.dark-mode .info-text {
    color: #a0aec0;
}

.example {
    background: #e6fffa;
    padding: 12px;
    border-radius: 6px;
    margin-top: 15px;
    font-size: 13px;
    border-left: 3px solid #14b8a6;
}

body.dark-mode .example {
    background: rgba(20, 184, 166, 0.15);
    color: #5eead4;
    border-left: 3px solid #2dd4bf;
}

.example strong {
    color: #0f766e;
}

body.dark-mode .example strong {
    color: #5eead4;
}

.mouse-controls {
    margin-top: 20px;
    padding-top: 15px;
    border-top: 2px solid #e2e8f0;
    font-size: 12px;
    color: #718096;
}

body.dark-mode .mouse-controls {
    border-top-color: #475569;
    color: #cbd5e0;
}

.axis-legend {
    display: flex;
    gap: 15px;
    margin: 15px 0;
    font-size: 13px;
}
.axis-item {
    display: flex;
    align-items: center;
    gap: 5px;
}
.axis-color {
    width: 20px;
    height: 20px;
    border-radius: 4px;
}

/* Equation Mode Styles */
.equation-help {
    background: #fef3c7;
    padding: 12px;
    border-radius: 6px;
    margin-bottom: 15px;
    font-size: 12px;
    border-left: 3px solid #f59e0b;
    line-height: 1.6;
}

body.dark-mode .equation-help {
    background: rgba(245, 158, 11, 0.15);
    color: #fcd34d;
    border-left: 3px solid #fbbf24;
}

.equation-help strong {
    color: #d97706;
}

body.dark-mode .equation-help strong {
    color: #fcd34d;
}

#equations-container {
    margin-bottom: 15px;
}

.equation-item {
    background: #f7fafc;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 12px;
    position: relative;
    border-left: 4px solid #cbd5e0;
}

body.dark-mode .equation-item {
    background: rgba(30, 41, 59, 0.3);
    border-left: 4px solid #60a5fa;
}

.equation-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.equation-label {
    font-weight: 600;
    color: #2d3748;
    display: flex;
    align-items: center;
    gap: 8px;
}

body.dark-mode .equation-label {
    color: #f1f5f9;
}

.color-indicator {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    display: inline-block;
}

.remove-equation-btn {
    background: #ef4444;
    color: white;
    border: none;
    border-radius: 4px;
    padding: 4px 12px;
    font-size: 12px;
    cursor: pointer;
    margin-top: 0;
    width: auto;
}

.remove-equation-btn:hover {
    background: #dc2626;
    transform: none;
}

.equation-input-wrapper {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.equation-input {
    width: 100%;
    padding: 10px;
    border: 2px solid #e2e8f0;
    border-radius: 6px;
    font-size: 14px;
    font-family: 'Courier New', monospace;
}

body.dark-mode .equation-input {
    background: rgba(15, 23, 42, 0.6);
    border-color: rgba(71, 85, 105, 0.4);
    color: #f1f5f9;
}

.equation-input:focus {
    outline: none;
    border-color: #3b82f6;
}

body.dark-mode .equation-input:focus {
    background: rgba(15, 23, 42, 0.8);
    border-color: #60a5fa;
}

.equation-input-help {
    font-size: 11px;
    color: #718096;
    font-style: italic;
}

body.dark-mode .equation-input-help {
    color: #a0aec0;
}

.add-equation-btn {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    margin-bottom: 10px;
}

.add-equation-btn:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    color: #64748b;
}

.add-equation-btn:disabled:hover {
    transform: none;
    box-shadow: none;
}

.equation-buttons {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.intersection-btn {
    background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
    margin-top: 0;
}

/* Footer Styles */
#footer {
    position: fixed;
    bottom: 15px;
    right: 20px;
    background: rgba(255, 255, 255, 0.95);
    padding: 10px 20px;
    border-radius: 8px;
    font-size: 13px;
    color: #334155;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    z-index: 50;
}

body.dark-mode #footer {
    background: rgba(30, 41, 59, 0.95);
    color: #cbd5e0;
    border: 1px solid rgba(148, 163, 184, 0.2);
}

#footer strong {
    color: #3b82f6;
}

body.dark-mode #footer strong {
    color: #60a5fa;
}