:root {
    --bg: #f5f0eb;
    --accent: #6b5e62;
    --danger: #b8908a;
}

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

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
    background: var(--bg);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    -webkit-tap-highlight-color: transparent;
}

.container {
    background: #fff;
    border-radius: 20px;
    padding: 28px 24px 22px;
    width: 100%;
    max-width: 700px;
    box-shadow: 0 16px 48px rgba(60, 50, 50, 0.12);
    display: flex;
    flex-direction: column;
    gap: 16px;
    border: 1px solid #e0d8cf;
}

.header {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.25rem;
    font-weight: 600;
    color: #3e3640;
}

.header .icon {
    width: 34px;
    height: 34px;
    background: #f0e8e0;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
}

.settings {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    padding: 10px 14px;
    background: #faf8f5;
    border-radius: 14px;
    border: 1px solid #e0d8cf;
    align-items: center;
}

.setting {
    display: flex;
    align-items: center;
    gap: 5px;
    font-size: 0.85rem;
    color: #3e3640;
    white-space: nowrap;
}

.setting input[type="color"] {
    width: 28px;
    height: 26px;
    border: 2px solid #e0d8cf;
    border-radius: 6px;
    cursor: pointer;
    padding: 2px;
    background: transparent;
}

.setting input[type="range"] {
    width: 60px;
    height: 6px;
    border-radius: 3px;
    background: #e0d8cf;
    -webkit-appearance: none;
    cursor: pointer;
}

.setting input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent);
    border: 2px solid #fff;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

.setting input[type="number"] {
    width: 48px;
    padding: 3px 4px;
    border: 2px solid #e0d8cf;
    border-radius: 6px;
    font-size: 0.85rem;
    text-align: center;
    background: #fff;
}

.setting input[type="checkbox"] {
    width: 16px;
    height: 16px;
    accent-color: var(--accent);
}

.hidden-control {
    display: none;
}

.hidden-mobile {
    display: none;
}

.pen-size-val {
    min-width: 18px;
    display: inline-block;
    font-weight: 600;
}

.canvas-wrapper {
    position: relative;
    border-radius: 14px;
    overflow: hidden;
    border: 2px dashed #d9cfc3;
    background: #fff;
    cursor: crosshair;
    aspect-ratio: 3 / 1.4;
    min-height: 190px;
    user-select: none;
    -webkit-user-select: none;
}

canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

#gridCanvas {
    pointer-events: none;
}

#signatureCanvas {
    touch-action: none;
}

.placeholder {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    pointer-events: none;
    color: #c5b9aa;
    font-size: 0.95rem;
    transition: opacity 0.3s;
    text-align: center;
    z-index: 2;
}

.placeholder.hidden {
    opacity: 0;
}

.actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 9px 17px;
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    border: none;
    font-family: inherit;
    outline: none;
}

.btn-undo {
    background: #f3efea;
    color: #3e3640;
}

.btn-undo:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    pointer-events: none;
}

.btn-clear {
    background: #fdf3f1;
    color: var(--danger);
}

.btn-export {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 4px 14px rgba(107, 94, 98, 0.25);
}

.btn-export.success-flash {
    background: #5a8a6a;
}

.toast {
    position: fixed;
    top: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(-120px);
    background: #3e3640;
    color: #fff;
    padding: 9px 20px;
    border-radius: 50px;
    font-size: 0.85rem;
    z-index: 999;
    pointer-events: none;
    opacity: 0;
    transition: all 0.4s ease;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

.footer {
    display: flex;
    justify-content: center;
    gap: 16px;
    font-size: 0.78rem;
    color: #b0a49a;
}

.footer a {
    color: #9a8e86;
    text-decoration: none;
    transition: color 0.2s;
}

.footer a:hover {
    color: var(--accent);
}

@media (max-width: 500px) {
    .container {
        padding: 16px 12px 14px;
        gap: 12px;
    }

    .settings {
        gap: 8px;
    }

    .btn {
        padding: 8px 13px;
        font-size: 0.82rem;
    }

    .hidden-mobile {
        display: flex;
    }

    .landscape-mode {
        position: fixed;
        top: 0;
        left: 100vw;
        width: 100vh;
        height: 100vw;
        max-width: none;
        transform: rotate(90deg);
        transform-origin: top left;
        border-radius: 0;
        padding: 10px 14px;
        gap: 6px;
        z-index: 1000;
    }

    .landscape-mode .header {
        font-size: 1rem;
        gap: 6px;
    }

    .landscape-mode .header .icon {
        width: 28px;
        height: 28px;
    }

    .landscape-mode .settings {
        padding: 6px 10px;
        gap: 6px;
    }

    .landscape-mode .setting {
        font-size: 0.78rem;
    }

    .landscape-mode .canvas-wrapper {
        aspect-ratio: unset;
        flex: 1;
        min-height: 0;
    }

    .landscape-mode .actions {
        gap: 8px;
    }

    .landscape-mode .btn {
        padding: 6px 12px;
        font-size: 0.78rem;
    }

    .landscape-mode .footer {
        font-size: 0.7rem;
        gap: 10px;
    }
}