.app {
    display: grid;
    grid-template-columns: 220px 1fr 280px;
    grid-template-rows: 54px 1fr;
    height: 100vh;
}

header {
    grid-column: 1 / 4;
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 0 20px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-primary);
    flex-wrap: wrap;
    transition: background var(--transition-speed), border-color var(--transition-speed);
}

header h1 {
    margin: 0;
    font-size: 18px;
    font-weight: 600;
    letter-spacing: 0.3px;
    background: linear-gradient(135deg, #b7c9ff, #7f9aff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: flex;
    align-items: center;
    gap: 8px;
}

header .brand {
    font-size: 11px;
    background: var(--bg-panel);
    padding: 2px 12px;
    border-radius: 20px;
    border: 1px solid var(--border-secondary);
    color: var(--text-secondary);
    -webkit-text-fill-color: var(--text-secondary);
    transition: background var(--transition-speed), color var(--transition-speed), border-color var(--transition-speed);
}

header .version {
    color: var(--text-secondary);
    font-size: 12px;
    background: var(--bg-panel);
    padding: 2px 12px;
    border-radius: 20px;
    border: 1px solid var(--border-secondary);
    transition: background var(--transition-speed), color var(--transition-speed), border-color var(--transition-speed);
}

.header-actions {
    display: flex;
    gap: 8px;
    margin-left: auto;
    flex-wrap: wrap;
}

button {
    border: 1px solid var(--border-tool);
    background: var(--bg-panel);
    color: var(--text-primary);
    border-radius: 6px;
    padding: 6px 14px;
    font-size: 13px;
    cursor: pointer;
    transition: background 0.15s, border-color 0.15s, box-shadow 0.15s, color 0.15s;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

button:hover {
    background: var(--bg-secondary);
    border-color: var(--border-active);
}

button.active {
    background: #3b445a;
    border-color: var(--border-active);
    box-shadow: 0 0 0 1px #5f72a0;
}
[data-theme="light"] button.active {
    background: #d0d8e8;
    border-color: var(--border-active);
}

button.danger {
    border-color: var(--color-danger);
    color: #f2b9c4;
}
button.danger:hover {
    background: #442a31;
    border-color: #ac5d6c;
}
[data-theme="light"] button.danger:hover {
    background: #e8d0d4;
    border-color: #ac5d6c;
}

button.success {
    border-color: var(--color-success);
    color: #8fdfb0;
}
button.success:hover {
    background: #1e3d2e;
    border-color: #5aaa7a;
}
[data-theme="light"] button.success:hover {
    background: #d0e8d8;
    border-color: #5aaa7a;
}

.theme-toggle {
    font-size: 16px;
    padding: 4px 10px;
    background: var(--bg-panel);
    border-color: var(--border-tool);
    transition: background var(--transition-speed), border-color var(--transition-speed);
}
.theme-toggle:hover {
    background: var(--bg-secondary);
}

.left,
.right {
    background: var(--bg-panel);
    padding: 16px 14px;
    overflow-y: auto;
    transition: background var(--transition-speed);
}

.left {
    border-right: 1px solid var(--border-secondary);
}

.right {
    border-left: 1px solid var(--border-secondary);
    background: var(--bg-secondary);
}

.panel-title {
    color: var(--text-secondary);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 1.2px;
    margin: 6px 0 12px;
    font-weight: 500;
    transition: color var(--transition-speed);
}

.tool {
    width: 100%;
    margin-bottom: 8px;
    text-align: left;
    background: var(--bg-secondary);
    border-color: var(--border-secondary);
}
.tool.active {
    border-color: var(--border-active);
    background: var(--bg-panel);
}
[data-theme="light"] .tool.active {
    background: #d0d8e8;
}

.help {
    margin-top: 28px;
    color: var(--text-muted);
    font-size: 12px;
    line-height: 1.7;
    border-top: 1px solid var(--border-secondary);
    padding-top: 16px;
    transition: color var(--transition-speed), border-color var(--transition-speed);
}
.help b {
    color: var(--text-secondary);
    transition: color var(--transition-speed);
}
.help kbd {
    background: var(--bg-secondary);
    padding: 1px 8px;
    border-radius: 4px;
    font-size: 11px;
    color: var(--text-secondary);
    border: 1px solid var(--border-tool);
    transition: background var(--transition-speed), color var(--transition-speed), border-color var(--transition-speed);
}

.brand-footer {
    margin-top: 16px;
    padding-top: 12px;
    border-top: 1px solid var(--border-secondary);
    text-align: center;
    font-size: 11px;
    color: var(--text-muted);
    transition: color var(--transition-speed), border-color var(--transition-speed);
}
.brand-footer .clover {
    color: var(--pixel-clover);
    font-weight: 600;
    transition: color var(--transition-speed);
}

#workspace {
    position: relative;
    overflow: hidden;
    background-color: var(--bg-workspace);
    cursor: grab;
    touch-action: none;
    transition: background var(--transition-speed);
}

#workspace:active {
    cursor: grabbing;
}

#workspace .grid-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        linear-gradient(var(--grid-line) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
    background-size: 28px 28px;
    pointer-events: none;
    transition: background-image var(--transition-speed);
}

#workspace .content-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    transform-origin: 0 0;
    pointer-events: auto;
}