:root {
    --editor-bg: #08080f;
    --surface-1: #121218;
    --surface-2: #1c1c26;
    --surface-3: #2a2a38;
    --surface-glass: rgba(18, 18, 26, 0.72);
    --surface-glass-strong: rgba(14, 14, 20, 0.86);
    --border-color: #2f2f3d;
    --border-subtle: rgba(255, 255, 255, 0.07);
    --text-primary: #f7f7fb;
    --text-secondary: #9a9aac;
    --text-tertiary: #5c5c70;

    --brand-primary: #3b82f6;
    --brand-secondary: #2563eb;
    --brand-primary-t: rgba(59, 130, 246, 0.14);
    --brand-gradient: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    --brand-gradient-soft: linear-gradient(135deg, rgba(59,130,246,0.16) 0%, rgba(37,99,235,0.16) 100%);
    --danger: #ef4444;
    --danger-t: rgba(239, 68, 68, 0.14);
    --success: #10b981;
    --success-t: rgba(16, 185, 129, 0.14);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 999px;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.22);
    --shadow-md: 0 6px 18px -6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 20px 48px -12px rgba(0, 0, 0, 0.55);
    --shadow-glow: 0 0 0 1px rgba(59, 130, 246, 0.22), 0 8px 28px -6px rgba(59, 130, 246, 0.32), 0 16px 40px -12px rgba(139, 92, 246, 0.24);

    --fs-2xs: 11px;
    --fs-xs: 12px;
    --fs-sm: 13px;
    --fs-md: 14px;
    --fs-base: 15px;
    --fs-lg: 18px;
    --fs-xl: 20px;
    --fs-2xl: 28px;

    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-spring: 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);

    --header-h: 64px;
    --sidebar-w: 80px;
    --panel-w: 320px;
    --safe-b: env(safe-area-inset-bottom, 0px);
    --safe-t: env(safe-area-inset-top, 0px);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--editor-bg);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: var(--fs-base);
    line-height: 1.5;
    overflow: hidden;
    overscroll-behavior: contain;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

:focus-visible {
    outline: 2px solid var(--brand-primary);
    outline-offset: 2px;
    border-radius: 4px;
}

::selection { background: var(--brand-primary-t); color: var(--text-primary); }

::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--surface-3); border-radius: var(--radius-sm); }
::-webkit-scrollbar-thumb:hover { background: var(--text-tertiary); }

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes rotation {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}
@keyframes modalBg { from { opacity: 0; } to { opacity: 1; } }
@keyframes modalSlideUp {
    from { opacity: 0; transform: translateY(20px) scale(0.96); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}
@keyframes pulseBorder {
    0% { border-color: var(--brand-primary); box-shadow: 0 0 0 0 rgba(59,130,246,0.25); }
    50% { border-color: var(--brand-secondary); box-shadow: 0 0 0 12px rgba(37,99,235,0); }
    100% { border-color: var(--brand-primary); box-shadow: 0 0 0 0 rgba(59,130,246,0); }
}
@keyframes toast-in {
    from { opacity: 0; transform: translateY(20px) scale(0.9); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}
@keyframes toast-out {
    from { opacity: 1; transform: scale(1); }
    to { opacity: 0; transform: scale(0.92); }
}
@keyframes slideUp {
    from { transform: translateY(100%); }
    to { transform: translateY(0); }
}
@keyframes spinGradient {
    to { transform: rotate(360deg); }
}

.upload-prompt-overlay {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background:
        radial-gradient(circle at 50% 15%, rgba(59, 130, 246, 0.10), transparent 55%),
        radial-gradient(circle at 85% 85%, rgba(139, 92, 246, 0.08), transparent 55%),
        var(--editor-bg);
    padding: 24px;
    z-index: 100;
}

body.upload-active,
body.upload-active .editor-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    width: 100%;
}

body.editor-active #main-header,
body.editor-active #main-footer {
    display: none;
}

.main-view {
    display: flex;
    flex-direction: column;
    height: 100vh;
    height: 100dvh;
    background: var(--surface-1);
    overflow: hidden;
}

.editor-layout {
    display: flex;
    flex-grow: 1;
    overflow: hidden;
    position: relative;
    min-height: 0;
}

.top-bar {
    display: flex;
    align-items: center;
    padding: 12px 24px;
    padding-top: calc(12px + var(--safe-t));
    background: var(--surface-glass-strong);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-subtle);
    flex-shrink: 0;
    gap: 16px;
    height: var(--header-h);
    z-index: 10;
}

.upload-card {
    width: 100%;
    max-width: 520px;
    padding: 32px;
    background: var(--surface-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-subtle);
    box-shadow: var(--shadow-lg);
    transform: scale(1);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
    position: relative;
    z-index: 1;
}

.upload-card:hover {
    border-color: rgba(59, 130, 246, 0.35);
    box-shadow: var(--shadow-glow);
    transform: translateY(-2px);
}

.upload-card-header { text-align: center; margin-bottom: 32px; }
.upload-card-title {
    font-size: var(--fs-2xl);
    font-weight: 800;
    color: var(--text-primary);
    margin: 0 0 8px 0;
    letter-spacing: -0.03em;
}
.upload-card-subtitle { font-size: var(--fs-base); color: var(--text-secondary); margin: 0; }

.drop-zone {
    background: rgba(255, 255, 255, 0.015);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    text-align: center;
    cursor: pointer;
    transition: border-color var(--transition-normal), background-color var(--transition-normal), transform var(--transition-fast);
    padding: 48px 24px;
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--brand-primary);
    background: var(--brand-gradient-soft);
}
.drop-zone.dragover { transform: scale(1.01); }
.drop-zone:hover .drop-icon { transform: scale(1.1) translateY(-2px); }

.upload-info { display: flex; flex-direction: column; align-items: center; gap: 16px; }
.drop-icon {
    font-size: 48px;
    line-height: 1;
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    transition: transform var(--transition-spring);
}
.drop-title { font-size: var(--fs-lg); font-weight: 700; color: var(--text-primary); margin: 0; }
.drop-desc { font-size: var(--fs-md); color: var(--text-secondary); margin: 0; }

.features-list { list-style: none; display: flex; justify-content: center; flex-wrap: wrap; gap: 20px; font-size: var(--fs-sm); font-weight: 500; color: var(--text-secondary); margin-top: 28px; }
.features-list li { display: flex; align-items: center; gap: 8px; }
.features-list i { color: var(--brand-primary); font-size: var(--fs-md); }

#filename-display {
    font-size: var(--fs-md);
    font-weight: 600;
    color: var(--text-secondary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    padding: 0 16px;
    flex-grow: 1;
    text-align: center;
}
.top-bar-actions { display: flex; align-items: center; gap: 12px; }

.history-btn, .top-bar-btn {
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    font-family: inherit;
    transition: background-color var(--transition-fast), color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast), border-color var(--transition-fast);
}

.history-btn {
    padding: 8px 12px;
    background-color: var(--surface-2);
    color: var(--text-secondary);
    border: 1px solid transparent;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    min-height: 36px;
}
.history-btn:not(:disabled):hover { color: var(--text-primary); background-color: var(--surface-3); transform: translateY(-1px); }
.history-btn:not(:disabled):active { transform: translateY(0) scale(0.96); }
.history-btn:disabled { opacity: 0.35; cursor: not-allowed; }

.top-bar-btn { padding: 8px 16px; font-size: var(--fs-md); font-weight: 600; display: flex; align-items: center; gap: 8px; min-height: 36px; }
.top-bar-btn:disabled { opacity: 0.45; cursor: not-allowed; }
.top-bar-btn.primary {
    background: var(--brand-gradient);
    color: white;
    box-shadow: 0 1px 0 rgba(255,255,255,0.12) inset;
}
.top-bar-btn.primary:hover:not(:disabled) { filter: brightness(1.08); box-shadow: 0 4px 16px -2px rgba(59, 130, 246, 0.45); transform: translateY(-1px); }
.top-bar-btn.primary:active:not(:disabled) { transform: translateY(0) scale(0.98); filter: brightness(0.96); }
.top-bar-btn.secondary { background-color: var(--surface-2); color: var(--text-primary); border: 1px solid var(--border-subtle); }
.top-bar-btn.secondary:hover:not(:disabled) { background-color: var(--surface-3); transform: translateY(-1px); }
.top-bar-btn.secondary:active:not(:disabled) { transform: translateY(0) scale(0.98); }

.tools-sidebar {
    width: var(--sidebar-w);
    background: var(--surface-1);
    border-right: 1px solid var(--border-subtle);
    padding: 16px 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
    z-index: 5;
    overflow-y: auto;
}
.tool-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    width: 64px;
    height: 64px;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-family: inherit;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    position: relative;
    transition: background-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}
.tool-btn i { font-size: var(--fs-xl); transition: transform var(--transition-fast); }
.tool-btn span { font-size: var(--fs-2xs); font-weight: 600; letter-spacing: 0.01em; }
.tool-btn:hover { color: var(--text-primary); background-color: var(--surface-2); }
.tool-btn:hover i { transform: translateY(-1px); }
.tool-btn:active { transform: scale(0.94); }
.tool-btn.active { color: var(--brand-primary); background-color: var(--brand-primary-t); }
.tool-btn.active::before {
    content: '';
    position: absolute;
    left: -8px;
    top: 50%;
    transform: translateY(-50%);
    height: 28px;
    width: 4px;
    background: var(--brand-gradient);
    border-radius: 0 4px 4px 0;
    box-shadow: 0 0 10px rgba(59, 130, 246, 0.6);
}

.reset-btn { margin-top: auto; color: var(--danger); }
.reset-btn:hover { background: var(--danger-t); color: var(--danger); }

.canvas-wrapper {
    flex-grow: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    background:
        radial-gradient(circle at 50% 0%, rgba(59, 130, 246, 0.05), transparent 60%),
        var(--editor-bg);
    padding: 24px;
    overflow: auto;
    position: relative;
}
.canvas-container {
    position: relative;
    line-height: 0;
    box-shadow: var(--shadow-lg);
    border-radius: 4px;
    background-image:
        linear-gradient(45deg, #1b1b25 25%, transparent 25%),
        linear-gradient(-45deg, #1b1b25 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #1b1b25 75%),
        linear-gradient(-45deg, transparent 75%, #1b1b25 75%);
    background-size: 16px 16px;
    background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
    background-color: #101018;
}
.canvas-container.empty { width: 100%; height: 100%; box-shadow: none; background: none; }
#editor-canvas, #drawing-canvas { max-width: 100%; max-height: 100%; object-fit: contain; border-radius: 4px; display: block; }
#drawing-canvas { position: absolute; top: 0; left: 0; cursor: none; pointer-events: none; touch-action: none; }
#brush-cursor-preview {
    position: fixed;
    border: 1.5px solid #fff;
    border-radius: 50%;
    transform: translate(-50%, -50%);
    pointer-events: none;
    z-index: 9999;
    display: none;
    mix-blend-mode: difference;
}

.options-panel-container {
    width: var(--panel-w);
    background: var(--surface-1);
    border-left: 1px solid var(--border-subtle);
    padding: 24px;
    overflow-y: auto;
    flex-shrink: 0;
    transition: transform var(--transition-normal), width var(--transition-normal);
    z-index: 5;
}
.options-panel { display: none; }
.options-panel.active { display: block; animation: fadeIn var(--transition-fast); }
.panel-title { font-size: var(--fs-lg); font-weight: 700; margin-bottom: 8px; color: var(--text-primary); letter-spacing: -0.01em; }
.panel-desc { font-size: var(--fs-sm); color: var(--text-secondary); margin-bottom: 24px; line-height: 1.55; }

.slider-group { margin-bottom: 24px; }
.slider-group label { display: flex; align-items: center; justify-content: space-between; font-size: var(--fs-sm); color: var(--text-primary); margin-bottom: 12px; font-weight: 600; }
.slider-group label > div:first-child { display: flex; align-items: center; }
.slider-value { background: var(--surface-2); padding: 2px 8px; border-radius: var(--radius-sm); font-variant-numeric: tabular-nums; color: var(--text-primary); border: 1px solid var(--border-subtle); }

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    border-radius: var(--radius-sm);
    outline: none;
    background: linear-gradient(to right, var(--brand-primary) var(--pct, 50%), var(--surface-2) var(--pct, 50%));
    transition: box-shadow var(--transition-fast);
    cursor: pointer;
}
input[type="range"]:hover { box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.08); }
input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: #fff;
    cursor: pointer;
    border: 3px solid var(--brand-primary);
    box-shadow: var(--shadow-sm);
    transition: transform 0.1s, box-shadow var(--transition-fast);
}
input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.15); box-shadow: 0 0 0 6px rgba(59, 130, 246, 0.16); }
input[type="range"]::-webkit-slider-thumb:active { transform: scale(1.05); border-color: var(--brand-purple); }
input[type="range"]::-moz-range-track { background: var(--surface-2); height: 6px; border-radius: var(--radius-sm); }
input[type="range"]::-moz-range-progress { background: var(--brand-primary); height: 6px; border-radius: var(--radius-sm); }
input[type="range"]::-moz-range-thumb {
    width: 18px; height: 18px; border-radius: 50%; background: #fff;
    border: 3px solid var(--brand-primary); cursor: pointer; box-shadow: var(--shadow-sm);
    transition: transform 0.1s;
}
input[type="range"]::-moz-range-thumb:hover { transform: scale(1.15); }

.button-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(100px, 1fr)); gap: 10px; }
.option-btn {
    padding: 12px;
    background: var(--surface-2);
    border: 1px solid var(--border-subtle);
    color: var(--text-primary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-family: inherit;
    font-size: var(--fs-sm);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    font-weight: 600;
    position: relative;
    transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}
.option-btn i { font-size: var(--fs-lg); color: var(--text-secondary); transition: color var(--transition-fast); }
.option-btn:hover { background: var(--surface-3); transform: translateY(-1px); }
.option-btn:hover i { color: var(--text-primary); }
.option-btn:active { transform: translateY(0) scale(0.97); }
.option-btn.active, #text-bold-btn[data-active="true"], #text-italic-btn[data-active="true"] {
    background: var(--brand-gradient-soft);
    border-color: rgba(59, 130, 246, 0.35);
    color: var(--brand-primary);
}
.option-btn.active i, #text-bold-btn[data-active="true"] i, #text-italic-btn[data-active="true"] i { color: var(--brand-primary); }

.font-options { display: flex; flex-direction: column; gap: 16px; }
.font-options input[type="text"], .font-options select {
    width: 100%;
    padding: 12px;
    background: var(--surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: inherit;
    font-size: var(--fs-md);
    outline: none;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.font-options input[type="text"]:focus, .font-options select:focus { border-color: var(--brand-primary); box-shadow: 0 0 0 3px var(--brand-primary-t); }

.color-picker-wrapper { display: flex; align-items: center; gap: 12px; background: var(--surface-2); padding: 8px 12px; border-radius: var(--radius-sm); border: 1px solid var(--border-subtle); }
.color-picker-wrapper input[type="color"] { width: 32px; height: 32px; border: none; padding: 0; background: none; border-radius: 50%; overflow: hidden; cursor: pointer; }
.color-picker-wrapper input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
.color-picker-wrapper input[type="color"]::-webkit-color-swatch { border: none; border-radius: 50%; box-shadow: inset 0 0 0 1px rgba(255,255,255,0.2); }
.color-picker-wrapper .eyedropper-btn { font-size: var(--fs-lg); color: var(--text-secondary); background: none; border: none; cursor: pointer; transition: color var(--transition-fast); }
.color-picker-wrapper .eyedropper-btn:hover { color: var(--text-primary); }
.color-picker-wrapper .eyedropper-btn.active { color: var(--brand-primary); }

.loader-overlay {
    position: absolute;
    inset: 0;
    background: rgba(8, 8, 15, 0.72);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    display: none;
    align-items: center;
    flex-direction: column;
    justify-content: center;
    gap: 16px;
    z-index: 1000;
}
.loader-overlay.visible { display: flex; }
.spinner {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: conic-gradient(from 0deg, var(--brand-primary), var(--brand-secondary), var(--brand-primary));
    -webkit-mask: radial-gradient(farthest-side, transparent calc(100% - 4px), #000 calc(100% - 4px));
    mask: radial-gradient(farthest-side, transparent calc(100% - 4px), #000 calc(100% - 4px));
    animation: spinGradient 0.9s linear infinite;
}
.loader-text { font-size: var(--fs-base); font-weight: 600; color: var(--text-primary); letter-spacing: 0.02em; }

.modal { display: none; position: fixed; z-index: 1001; inset: 0; background-color: rgba(4,4,8,0.65); backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px); align-items: center; justify-content: center; padding: 20px; }
.modal.is-visible { display: flex; animation: modalBg var(--transition-fast); }
.modal-content {
    background-color: var(--surface-1);
    background-image: var(--brand-gradient-soft);
    background-repeat: no-repeat;
    background-size: 100% 120px;
    padding: 32px;
    border: 1px solid var(--border-subtle);
    width: 100%;
    max-width: 420px;
    max-height: calc(100vh - 40px);
    overflow-y: auto;
    border-radius: var(--radius-xl);
    position: relative;
    box-shadow: var(--shadow-lg);
    animation: modalSlideUp var(--transition-normal);
}
.modal-title { margin-top: 0; margin-bottom: 24px; font-size: var(--fs-xl); font-weight: 800; letter-spacing: -0.01em; }
.close-btn { position: absolute; top: 24px; right: 24px; font-size: var(--fs-xl); color: var(--text-secondary); cursor: pointer; line-height: 1; padding: 8px; margin: -8px; border-radius: 50%; transition: color var(--transition-fast), background-color var(--transition-fast); }
.close-btn:hover { color: var(--text-primary); background-color: var(--surface-2); }
.setting-item { margin-bottom: 20px; }
.setting-item label { display: block; margin-bottom: 10px; font-size: var(--fs-md); font-weight: 600; color: var(--text-primary); }
.modal-input { width: 100%; padding: 12px; background: var(--editor-bg); border: 1px solid var(--border-color); border-radius: var(--radius-sm); color: var(--text-primary); font-family: inherit; font-size: var(--fs-md); outline: none; transition: border-color var(--transition-fast); }
.modal-input:focus { border-color: var(--brand-primary); box-shadow: 0 0 0 3px var(--brand-primary-t); }
#quality-setting { display: flex; align-items: center; gap: 16px; }
#quality-value { font-size: var(--fs-md); font-weight: 600; color: var(--text-primary); min-width: 40px; text-align: right; font-variant-numeric: tabular-nums; }
.modal-btn {
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: var(--radius-md);
    background: var(--brand-gradient);
    color: white;
    font-family: inherit;
    font-size: var(--fs-base);
    font-weight: 700;
    cursor: pointer;
    margin-top: 16px;
    transition: filter var(--transition-fast), transform 0.1s, box-shadow var(--transition-fast);
}
.modal-btn:hover { filter: brightness(1.08); box-shadow: 0 6px 20px -4px rgba(59, 130, 246, 0.45); }
.modal-btn:active { transform: scale(0.98); }

.drag-overlay { position: fixed; inset: 0; z-index: 9998; background: rgba(6, 6, 12, 0.86); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); display: flex; align-items: center; justify-content: center; opacity: 0; pointer-events: none; transition: opacity var(--transition-fast); }
.drag-overlay.visible { opacity: 1; }
.drag-overlay-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 24px;
    color: var(--text-primary);
    font-size: var(--fs-xl);
    font-weight: 800;
    text-align: center;
    border: 3px dashed var(--brand-primary);
    padding: 64px 96px;
    border-radius: var(--radius-xl);
    background: var(--brand-gradient-soft);
    animation: pulseBorder 2s infinite;
}
.drag-overlay-content i {
    font-size: 64px;
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

#toast-container {
    position: fixed;
    bottom: calc(24px + var(--safe-b));
    right: 24px;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 12px;
    pointer-events: none;
    max-width: calc(100vw - 48px);
}
.toast {
    display: flex;
    align-items: center;
    background: var(--surface-glass-strong);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    animation: toast-in 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    overflow: hidden;
    color: var(--text-primary);
    min-width: 280px;
    pointer-events: auto;
}
.toast.hiding { animation: toast-out 0.3s ease forwards; }
.toast-icon { padding: 16px; font-size: var(--fs-lg); align-self: stretch; display: flex; align-items: center; }
.toast.success .toast-icon { color: var(--success) !important; background: var(--success-t); }
.toast.error .toast-icon { color: var(--danger) !important; background: var(--danger-t); }
.toast.info .toast-icon { color: var(--brand-primary) !important; background: var(--brand-primary-t); }
.toast-sep { width: 1px; align-self: stretch; background: var(--border-subtle); }
.toast-msg { padding: 14px 16px; font-size: var(--fs-md); font-weight: 500; }

.tooltip-trigger { position: relative; display: inline-flex; align-items: center; margin-left: 8px; color: var(--text-secondary); cursor: help; padding: 4px; border-radius: 50%; transition: background-color var(--transition-fast); }
.tooltip-trigger .fa-question-circle { font-size: var(--fs-md); transition: color var(--transition-fast); }
.tooltip-trigger:hover { background-color: var(--surface-3); }
.tooltip-trigger:hover .fa-question-circle { color: var(--text-primary); }
.tooltip-content {
    position: absolute;
    display: block;
    opacity: 0;
    visibility: hidden;
    bottom: calc(100% + 10px);
    left: 50%;
    transform: translateX(-50%) translateY(5px);
    background-color: var(--surface-3);
    color: var(--text-primary);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: var(--fs-xs);
    font-weight: 500;
    width: max-content;
    max-width: 220px;
    z-index: 10000;
    text-align: center;
    line-height: 1.5;
    box-shadow: var(--shadow-md);
    transition: opacity var(--transition-fast), visibility var(--transition-fast), transform var(--transition-fast);
    pointer-events: none;
}
.tooltip-content::after { content: ''; position: absolute; top: 100%; left: 50%; transform: translateX(-50%); border-width: 5px; border-style: solid; border-color: var(--surface-3) transparent transparent transparent; }
.tooltip-trigger:hover .tooltip-content, .tooltip-trigger:focus-within .tooltip-content { opacity: 1; visibility: visible; transform: translateX(-50%) translateY(0); }
.option-btn .tooltip-trigger { position: absolute; top: 8px; right: 8px; margin: 0; }

@media (max-width: 1200px) {
    :root { --panel-w: 296px; }
}

@media (max-width: 992px) {
    .editor-layout { flex-direction: column; }

    .tools-sidebar {
        order: 3;
        width: 100%;
        height: 72px;
        flex-direction: row;
        justify-content: flex-start;
        border-right: none;
        border-top: 1px solid var(--border-subtle);
        padding: 0 12px;
        padding-bottom: var(--safe-b);
        gap: 6px;
        overflow-x: auto;
        overflow-y: hidden;
        background: var(--surface-glass-strong);
        backdrop-filter: blur(16px);
        -webkit-backdrop-filter: blur(16px);
    }
    .tools-sidebar::-webkit-scrollbar { display: none; }

    .tool-btn { height: 100%; width: 68px; flex-shrink: 0; }
    .tool-btn.active::before { left: 50%; top: 4px; transform: translateX(-50%); width: 28px; height: 3px; border-radius: 4px; }

    .reset-btn { margin-top: 0; margin-left: auto; }

    .options-panel-container {
        order: 2;
        width: 100%;
        max-height: 55vh;
        border-left: none;
        box-shadow: 0 -12px 32px rgba(0,0,0,0.45);
        display: none;
        padding: 28px 20px 24px;
        border-radius: var(--radius-xl) var(--radius-xl) 0 0;
        background: var(--surface-1);
        position: relative;
    }
    .options-panel-container::before {
        content: '';
        position: absolute;
        top: 10px;
        left: 50%;
        transform: translateX(-50%);
        width: 36px;
        height: 4px;
        background: var(--surface-3);
        border-radius: 4px;
    }
    .options-panel-container.visible { display: block; animation: slideUp var(--transition-normal); }

    .canvas-wrapper { order: 1; padding: 16px; }
}

@media (max-width: 768px) {
    .top-bar { padding: 10px 16px; padding-top: calc(10px + var(--safe-t)); height: 60px; gap: 10px; }

    .drop-zone { padding: 32px 16px; }

    #filename-display { display: none; }

    .history-btn, .top-bar-btn { padding: 8px 12px; min-height: 40px; }
    .top-bar-btn i { margin-right: 0; font-size: var(--fs-md); }
    .top-bar-btn > span { display: none; }

    .panel-title { margin-bottom: 12px; font-size: var(--fs-md); }
    .slider-group { margin-bottom: 18px; }
    .slider-group label { margin-bottom: 8px; }

    .features-list { flex-direction: column; align-items: flex-start; gap: 12px; margin-top: 24px; }
    .drag-overlay-content { padding: 40px 32px; text-align: center; font-size: var(--fs-lg); }
    .drag-overlay-content i { font-size: 48px; }

    #toast-container { left: 16px; right: 16px; bottom: calc(84px + var(--safe-b)); max-width: none; }
    .toast { min-width: unset; width: 100%; }

    .modal-content { padding: 24px; border-radius: var(--radius-lg); }
}

@media (max-width: 480px) {
    .upload-card { padding: 24px 20px; }
    .upload-card-title { font-size: var(--fs-xl); }
    .drop-zone { padding: 28px 14px; }
    .button-grid { grid-template-columns: repeat(auto-fit, minmax(84px, 1fr)); }
    .tool-btn { width: 60px; }
    .tool-btn span { display: none; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}