:root {
    --easing-standard: cubic-bezier(0.2, 0.0, 0, 1.0);
    --easing-emphasized: cubic-bezier(0.05, 0.7, 0.1, 1.0);
    --duration: 400ms;
    --primary: #000000;
    --surface: #ffffff;
    --surface-variant: #f4f4f4;
    --outline: #e0e0e0;
    --text-main: #111111;
    --text-sub: #767676;
}

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

body {
    background-color: var(--surface);
    color: var(--text-main);
    font-family: 'Noto Sans SC', system-ui, -apple-system, sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 64px 24px 120px;
}

header {
    width: 100%;
    max-width: 1080px;
    margin-bottom: 48px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

h1 {
    font-size: 40px;
    font-weight: 700;
    letter-spacing: -1px;
}

.icon-btn {
    background: none;
    border: none;
    cursor: pointer;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--duration) var(--easing-standard);
}

.icon-btn:hover {
    background-color: var(--surface-variant);
}

.icon-btn:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 8px;
}

main {
    width: 100%;
    max-width: 1080px;
    display: flex;
    flex-direction: column;
    gap: 40px;
}

/* 大号输入表单布局 */
.config-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
}

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

.input-group.span-2 {
    grid-column: span 2;
}

.input-group[hidden] {
    display: none;
}

label {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-sub);
    letter-spacing: 0.5px;
}

input, select {
    width: 100%;
    font-size: 20px;
    font-weight: 500;
    font-family: inherit;
    padding: 16px 20px;
    background-color: var(--surface);
    border: 2px solid var(--outline);
    border-radius: 20px;
    outline: none;
    color: var(--text-main);
    transition: all var(--duration) var(--easing-standard);
}

input:focus, select:focus {
    border-color: var(--primary);
    background-color: var(--surface);
    transform: translateY(-2px);
}

/* MD3 下拉触发器（替代浏览器默认下拉） */
.md-select {
    position: relative;
    width: 100%;
}

.md-select .native-select {
    display: none;
}

.md-select-trigger {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    font-size: 20px;
    font-weight: 500;
    font-family: inherit;
    text-align: left;
    padding: 16px 20px;
    background-color: var(--surface);
    border: 2px solid var(--outline);
    border-radius: 20px;
    color: var(--text-main);
    cursor: pointer;
    transition: all var(--duration) var(--easing-standard);
}

.md-select-trigger:hover {
    border-color: #bdbdbd;
}

.md-select-trigger:focus-visible,
.md-select.open .md-select-trigger {
    border-color: var(--primary);
    transform: translateY(-2px);
    outline: none;
}

.md-select-trigger .chevron {
    font-size: 24px;
    color: var(--text-sub);
    flex-shrink: 0;
    transition: transform 200ms var(--easing-standard);
}

.md-select.open .md-select-trigger .chevron {
    transform: rotate(180deg);
}

.md-select-value {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* MD3 menu 弹出层 */
.md-menu {
    position: fixed;
    z-index: 1200;
    min-width: 200px;
    padding: 8px 0;
    background-color: var(--surface);
    border-radius: 16px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.14), 0 2px 6px rgba(0, 0, 0, 0.08);
    opacity: 0;
    visibility: hidden;
    transform: scale(0.94);
    transform-origin: top center;
    pointer-events: none;
    transition: opacity 160ms var(--easing-standard), transform 160ms var(--easing-emphasized), visibility 0s linear 160ms;
    max-height: 320px;
    overflow-y: auto;
}

.md-menu.show {
    opacity: 1;
    visibility: visible;
    transform: scale(1);
    pointer-events: auto;
    transition: opacity 160ms var(--easing-standard), transform 160ms var(--easing-emphasized);
}

.md-menu-item {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    padding: 14px 20px;
    font-size: 17px;
    font-weight: 500;
    font-family: inherit;
    color: var(--text-main);
    background: none;
    border: none;
    text-align: left;
    cursor: pointer;
    transition: background 150ms var(--easing-standard);
}

.md-menu-item:hover,
.md-menu-item:focus-visible {
    background-color: var(--surface-variant);
    outline: none;
}

.md-menu-item[aria-selected="true"] {
    font-weight: 700;
}

.md-menu-item[aria-selected="true"]::after {
    content: "check";
    font-family: 'Material Symbols Outlined';
    font-size: 22px;
    margin-left: auto;
}

/* 自动排序开关 */
.switch-group {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 14px 20px;
    align-self: end;
    /* 横跨整行，容纳两组「标签 + 开关」，避免标签被挤到换行 */
    grid-column: 1 / -1;
    min-height: 64px;
}

.switch-label {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-sub);
    letter-spacing: 0.5px;
    white-space: nowrap;
    cursor: pointer;
}

.switch-item {
    display: inline-flex;
    align-items: center;
    gap: 20px;
}

.switch-item[hidden] {
    display: none;
}

.switch {
    position: relative;
    width: 64px;
    height: 36px;
    flex-shrink: 0;
    border-radius: 100px;
    border: 2px solid var(--outline);
    background-color: var(--surface-variant);
    cursor: pointer;
    transition: background var(--duration) var(--easing-standard), border-color var(--duration) var(--easing-standard);
}

.switch::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 6px;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background-color: var(--text-sub);
    transform: translateY(-50%);
    transition: left var(--duration) var(--easing-emphasized), width var(--duration) var(--easing-emphasized), height var(--duration) var(--easing-emphasized), background var(--duration) var(--easing-standard);
}

.switch[aria-checked="true"] {
    background-color: var(--primary);
    border-color: var(--primary);
}

.switch[aria-checked="true"]::after {
    left: 34px;
    width: 24px;
    height: 24px;
    background-color: var(--surface);
}

.switch:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 3px;
}

/* 操作按钮 */
.actions-row {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-top: 16px;
}

.btn-large {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 700;
    padding: 20px 36px;
    border-radius: 100px;
    cursor: pointer;
    border: none;
    transition: all var(--duration) var(--easing-emphasized);
}

.btn-primary {
    background-color: var(--primary);
    color: var(--surface);
}

.btn-primary:hover {
    transform: scale(1.02);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.12);
}

.btn-secondary {
    background-color: var(--surface-variant);
    color: var(--text-main);
}

.btn-secondary:hover {
    background-color: #e8e8e8;
    transform: scale(1.02);
}

.btn-large:active {
    transform: scale(0.98);
}

.btn-large:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* 色板结果容器 */
.palette-display-area {
    margin-top: 48px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    width: 100%;
}

.palette-row {
    display: flex;
    width: 100%;
    height: 80px;
    border-radius: 16px;
    overflow: hidden;
    background-color: var(--surface-variant);
    box-shadow: 0 4px 20px rgba(0,0,0,0.02);
    transition: transform var(--duration) var(--easing-standard);
}

.color-block {
    flex: 1 1 0;
    min-width: 0;
    height: 100%;
    cursor: pointer;
    opacity: 0;
    transform: scaleX(0.4);
    transform-origin: left center;
    /* 1px 同色外扩，覆盖亚像素渲染产生的白缝 */
    box-shadow: 0 0 0 1px currentColor;
    animation: blockPopIn 500ms var(--easing-emphasized) forwards;
    animation-fill-mode: forwards;
}

@keyframes blockPopIn {
    to {
        opacity: 1;
        transform: scaleX(1);
    }
}

@media (max-width: 560px) {
    body {
        padding: 40px 16px 80px;
    }

    h1 {
        font-size: 30px;
    }

    .config-grid {
        grid-template-columns: 1fr;
        gap: 18px;
    }

    .input-group.span-2 {
        grid-column: span 1;
    }

    .btn-large {
        flex: 1 1 100%;
        font-size: 18px;
        padding: 18px 24px;
    }

    .palette-row {
        height: 64px;
    }
}

/* 隐藏Canvas */
#exportCanvas {
    display: none;
}

/* MD3 弹窗 */
.dialog-scrim {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    background-color: rgba(0, 0, 0, 0.32);
    opacity: 0;
    pointer-events: none;
    transition: opacity 220ms var(--easing-standard);
}

.dialog-scrim.show {
    opacity: 1;
    pointer-events: auto;
}

.dialog {
    width: 100%;
    max-width: 480px;
    max-height: min(80vh, 640px);
    display: flex;
    flex-direction: column;
    background-color: var(--surface);
    border-radius: 28px;
    box-shadow: 0 24px 64px rgba(0, 0, 0, 0.2);
    transform: scale(0.92) translateY(12px);
    transition: transform 260ms var(--easing-emphasized);
    overflow: hidden;
}

.dialog-scrim.show .dialog {
    transform: scale(1) translateY(0);
}

.dialog.dialog-compact {
    max-width: 400px;
}

.dialog.dialog-about {
    max-width: 640px;
    max-height: min(86vh, 760px);
}

.about-section {
    padding: 8px;
}

.about-section + .about-section {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--outline);
}

.about-section h3 {
    font-size: 17px;
    font-weight: 700;
    letter-spacing: -0.2px;
}

.about-section p {
    margin-top: 8px;
    font-size: 14px;
    line-height: 1.7;
    color: var(--text-sub);
}

.about-section p.about-sub {
    margin-top: 14px;
    font-size: 13px;
    font-weight: 700;
    color: var(--text-main);
    letter-spacing: 0.4px;
}

.about-section ul {
    margin-top: 8px;
    padding-left: 20px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 14px;
    line-height: 1.7;
    color: var(--text-sub);
}

.about-section strong {
    color: var(--text-main);
}

.about-section code {
    padding: 1px 6px;
    border-radius: 6px;
    background-color: var(--surface-variant);
    font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
    font-size: 0.92em;
    color: var(--text-main);
    word-break: break-word;
}

.about-code {
    margin-top: 8px;
    padding: 14px 16px;
    border-radius: 12px;
    background-color: var(--surface-variant);
    font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
    font-size: 13px;
    line-height: 1.6;
    color: var(--text-main);
    white-space: pre-wrap;
    word-break: break-word;
}

.about-link {
    color: var(--text-main);
    font-weight: 700;
    text-decoration: underline;
    text-underline-offset: 3px;
    word-break: break-all;
}

.about-link:hover {
    color: var(--text-sub);
}

.dialog-head {
    padding: 24px 24px 12px;
}

.dialog-head h2 {
    font-size: 24px;
    font-weight: 700;
    letter-spacing: -0.3px;
    line-height: 1.35;
}

.dialog-head p {
    margin-top: 8px;
    font-size: 14px;
    color: var(--text-sub);
    line-height: 1.5;
}

.dialog-body {
    flex: 1;
    min-height: 0;
    overflow-y: auto;
    padding: 8px 16px 16px;
}

.dialog-body .field {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 8px;
}

.dialog-body .field input {
    font-size: 17px;
    padding: 14px 18px;
    border-radius: 16px;
}

.preset-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.preset-item {
    display: flex;
    align-items: center;
    gap: 4px;
    border-radius: 16px;
    transition: background 150ms var(--easing-standard);
}

.preset-item:hover,
.preset-item:focus-within {
    background-color: var(--surface-variant);
}

.preset-load {
    flex: 1;
    min-width: 0;
    display: block;
    padding: 12px 0 12px 16px;
    border: none;
    border-radius: 16px;
    background: none;
    font-family: inherit;
    text-align: left;
    color: inherit;
    cursor: pointer;
}

.preset-load:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: -2px;
}

.preset-meta {
    flex: 1;
    min-width: 0;
}

.preset-name {
    font-size: 17px;
    font-weight: 700;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.preset-sub {
    margin-top: 2px;
    font-size: 13px;
    color: var(--text-sub);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.preset-actions {
    display: flex;
    gap: 2px;
    flex-shrink: 0;
    padding-right: 8px;
}

.preset-actions .icon-btn {
    width: 40px;
    height: 40px;
}

.preset-actions .material-symbols-outlined {
    font-size: 22px;
    color: var(--text-sub);
}

.preset-empty {
    padding: 32px 16px;
    text-align: center;
    font-size: 15px;
    color: var(--text-sub);
    line-height: 1.6;
}

.dialog-foot {
    display: flex;
    justify-content: flex-end;
    gap: 8px;
    padding: 16px 24px 24px;
}

.btn-text {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-height: 48px;
    padding: 0 24px;
    border: none;
    border-radius: 100px;
    font-size: 16px;
    font-weight: 700;
    font-family: inherit;
    color: var(--text-sub);
    background: none;
    cursor: pointer;
    transition: background 150ms var(--easing-standard), color 150ms var(--easing-standard);
}

.btn-text:hover {
    background-color: var(--surface-variant);
    color: var(--text-main);
}

.btn-text.emphasis {
    color: var(--primary);
}

.btn-text.danger {
    color: #b3261e;
}

.btn-text.danger:hover {
    background-color: #fce8e6;
}

/* MD3 Snackbar */
.snackbar {
    position: fixed;
    left: 50%;
    bottom: 32px;
    z-index: 3000;
    display: flex;
    align-items: center;
    gap: 16px;
    max-width: min(560px, calc(100vw - 48px));
    padding: 16px 24px;
    border-radius: 12px;
    background-color: #1f1f1f;
    color: #ffffff;
    font-size: 15px;
    font-weight: 500;
    line-height: 1.4;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.24);
    opacity: 0;
    transform: translate(-50%, 24px);
    pointer-events: none;
    transition: opacity 220ms var(--easing-standard), transform 220ms var(--easing-emphasized);
}

.snackbar.show {
    opacity: 1;
    transform: translate(-50%, 0);
    pointer-events: auto;
}