* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-primary: #09090b;
    --bg-secondary: #0c0c0e;
    --bg-tertiary: #18181b;
    --text-primary: #b8b8bd;
    --text-secondary: #8a8a92;
    --accent: #b8b8bd;
    --accent-hover: #c8c8cd;
    --border: #27272a;
}

body {
    font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    overflow: hidden;
}

.app-container {
    display: flex;
    height: 100vh;
}

.sidebar {
    width: 400px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border);
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    overflow-y: auto;
    transition: transform 0.3s ease, width 0.3s ease;
    flex-shrink: 0;
}

.sidebar.collapsed {
    transform: translateX(-100%);
    width: 0;
    padding: 0;
    overflow: hidden;
}

.sidebar-toggle {
    position: absolute;
    left: 400px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 100;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-left: none;
    border-radius: 0 8px 8px 0;
    padding: 12px 8px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.sidebar-toggle:hover {
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.sidebar-toggle.collapsed {
    left: 0;
}

.sidebar-toggle svg {
    width: 16px;
    height: 16px;
    transition: transform 0.3s ease;
}

.sidebar-toggle.collapsed svg {
    transform: rotate(180deg);
}

.logo {
    font-size: 20px;
    font-weight: 600;
    letter-spacing: -0.5px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    width: 32px;
    height: 32px;
    background: #d0d0d5;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    color: #000000;
    font-weight: 600;
}

.section {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.section-title {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-secondary);
    font-weight: 500;
}

.formula-input-container {
    position: relative;
}

.formula-input {
    width: 100%;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 16px 18px;
    color: var(--text-primary);
    font-family: 'SF Mono', 'Fira Code', monospace;
    font-size: 16px;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
    min-height: 80px;
    resize: vertical;
    line-height: 1.5;
}

.formula-input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(250, 250, 250, 0.1);
}

.formula-input::placeholder {
    color: var(--text-secondary);
}

.formula-preview {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px 16px;
    margin-top: 8px;
    min-height: 40px;
    overflow-x: auto;
    text-align: center;
}

.formula-preview::-webkit-scrollbar {
    height: 6px;
}

.formula-preview::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
    border-radius: 3px;
}

.formula-preview::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 3px;
}

.formula-preview::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

.formula-preview .katex {
    font-size: 1.3em;
    color: var(--text-primary);
}

.formula-preview .katex-error {
    color: var(--text-secondary);
    font-size: 12px;
}

.presets-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    max-height: 200px;
    overflow-y: auto;
    padding-right: 4px;
}

.presets-grid::-webkit-scrollbar {
    width: 6px;
}

.presets-grid::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
    border-radius: 3px;
}

.presets-grid::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 3px;
}

.presets-grid::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

.preset-btn {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
    min-width: 0;
    overflow: hidden;
}

.preset-btn:hover {
    background: var(--bg-primary);
    border-color: var(--accent);
}

.preset-btn.active {
    border-color: var(--accent);
    background: rgba(250, 250, 250, 0.1);
}

.preset-name {
    font-size: 13px;
    font-weight: 500;
    margin-bottom: 4px;
}

.preset-formula {
    font-size: 10px;
    color: var(--text-secondary);
    font-family: 'SF Mono', 'Fira Code', monospace;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.params-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.param-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.param-label {
    font-size: 12px;
    color: var(--text-secondary);
}

.param-input {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px 12px;
    color: var(--text-primary);
    font-size: 13px;
    outline: none;
    width: 100%;
    transition: border-color 0.2s;
}

.param-input:focus {
    border-color: var(--accent);
}

.color-picker-container {
    display: flex;
    gap: 8px;
}

.color-option {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    cursor: pointer;
    border: 2px solid transparent;
    transition: all 0.2s;
}

.color-option:hover {
    transform: scale(1.1);
}

.color-option.active {
    border-color: var(--text-primary);
}

.generate-btn {
    background: #d0d0d5;
    border: none;
    border-radius: 10px;
    padding: 14px 24px;
    color: #000000;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    margin-top: auto;
}

.generate-btn:hover {
    background: #e0e0e5;
}

.generate-btn:active {
    background: #c0c0c5;
}

.canvas-container {
    flex: 1;
    position: relative;
    background: var(--bg-primary);
}

#chart-canvas {
    width: 100%;
    height: 100%;
    display: block;
}

.controls-hint {
    position: absolute;
    bottom: 20px;
    left: 20px;
    font-size: 12px;
    color: var(--text-secondary);
    background: var(--bg-secondary);
    padding: 10px 14px;
    border-radius: 8px;
    border: 1px solid var(--border);
    z-index: 10;
}

.formula-overlay {
    position: absolute;
    top: 20px;
    left: 20px;
    font-size: 12px;
    color: var(--text-secondary);
    background: var(--bg-secondary);
    padding: 10px 14px;
    border-radius: 8px;
    border: 1px solid var(--border);
    z-index: 10;
}

.formula-overlay .katex {
    font-size: 1.1em;
    color: var(--text-primary);
}

.error-toast {
    position: fixed;
    top: 20px;
    right: 20px;
    background: #ef4444;
    color: white;
    padding: 14px 20px;
    border-radius: 10px;
    font-size: 13px;
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.3s;
    pointer-events: none;
}

.error-toast.visible {
    opacity: 1;
    transform: translateY(0);
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 10px;
}

.checkbox-input {
    width: 18px;
    height: 18px;
    accent-color: var(--accent);
    cursor: pointer;
    border-radius: 6px;
}

.checkbox-label {
    font-size: 13px;
    color: var(--text-secondary);
    cursor: pointer;
}

/* Tablet breakpoint */
@media (max-width: 1024px) {
    .sidebar {
        width: 320px;
        padding: 20px;
        gap: 20px;
    }
    .sidebar-toggle {
        left: 320px;
    }
    .sidebar-toggle.collapsed {
        left: 0;
    }
    .formula-input {
        min-height: 60px;
        font-size: 14px;
    }
    .presets-grid {
        max-height: 150px;
    }
}

/* Small tablet / large phone breakpoint */
@media (max-width: 768px) {
    .app-container {
        flex-direction: column;
    }
    .sidebar {
        width: 100%;
        height: auto;
        max-height: 45vh;
        border-right: none;
        border-bottom: 1px solid var(--border);
        padding: 16px;
        gap: 16px;
    }
    .sidebar.collapsed {
        transform: translateY(-100%);
        max-height: 0;
    }
    .sidebar-toggle {
        left: auto;
        right: 16px;
        top: auto;
        bottom: 0;
        transform: translateY(100%);
        border-radius: 0 0 8px 8px;
        border: 1px solid var(--border);
        border-top: none;
        padding: 8px 16px;
    }
    .sidebar-toggle.collapsed {
        left: auto;
        position: fixed;
        top: 16px;
        right: 16px;
        bottom: auto;
        transform: none;
        border-radius: 8px;
        border: 1px solid var(--border);
    }
    .sidebar-toggle svg {
        transform: rotate(-90deg);
    }
    .sidebar-toggle.collapsed svg {
        transform: rotate(90deg);
    }
    .canvas-container {
        flex: 1;
        min-height: 55vh;
    }
    .logo {
        font-size: 18px;
    }
    .logo-icon {
        width: 28px;
        height: 28px;
        font-size: 14px;
    }
    .presets-grid {
        max-height: 120px;
    }
    .controls-hint {
        bottom: 12px;
        left: 12px;
        font-size: 11px;
        padding: 8px 12px;
    }
    .formula-overlay {
        top: 12px;
        left: 12px;
        font-size: 11px;
        padding: 8px 12px;
    }
}

/* Phone breakpoint */
@media (max-width: 480px) {
    .sidebar {
        padding: 12px;
        gap: 12px;
        max-height: 40vh;
    }
    .logo {
        font-size: 16px;
    }
    .logo-icon {
        width: 24px;
        height: 24px;
        font-size: 12px;
    }
    .section-title {
        font-size: 10px;
    }
    .formula-input {
        padding: 12px 14px;
        font-size: 13px;
        min-height: 50px;
    }
    .presets-grid {
        grid-template-columns: 1fr;
        max-height: 100px;
        gap: 6px;
    }
    .preset-btn {
        padding: 10px;
    }
    .preset-name {
        font-size: 12px;
    }
    .preset-formula {
        font-size: 9px;
    }
    .params-grid {
        grid-template-columns: 1fr 1fr;
        gap: 8px;
    }
    .param-label {
        font-size: 11px;
    }
    .param-input {
        padding: 8px 10px;
        font-size: 12px;
    }
    .color-picker-container {
        flex-wrap: wrap;
        gap: 6px;
    }
    .color-option {
        width: 24px;
        height: 24px;
    }
    .checkbox-group {
        gap: 8px;
    }
    .checkbox-input {
        width: 16px;
        height: 16px;
    }
    .checkbox-label {
        font-size: 12px;
    }
    .generate-btn {
        padding: 12px 20px;
        font-size: 13px;
    }
    .canvas-container {
        min-height: 60vh;
    }
    .controls-hint {
        bottom: 8px;
        left: 8px;
        right: auto;
        text-align: center;
        font-size: 10px;
        padding: 6px 10px;
    }
    .formula-overlay {
        top: 8px;
        left: 8px;
        font-size: 10px;
        padding: 6px 10px;
    }
}