:root {
    --color-bg: #f7f8fb;
    --color-surface: #ffffff;
    --color-border: #e4e7ee;
    --color-text: #1c1f2a;
    --color-text-muted: #6b7280;
    --color-primary: #4f46e5;
    --color-primary-hover: #4338ca;
    --color-info-bg: #eef2ff;
    --color-info-border: #c7d2fe;
    --color-info-text: #3730a3;
    --color-error-bg: #fef2f2;
    --color-error-border: #fecaca;
    --color-error-text: #991b1b;
    --radius: 14px;
    --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 8px 24px rgba(16, 24, 40, 0.06);
}

* {
    box-sizing: border-box;
}

html,
body {
    height: 100%;
}

body {
    margin: 0;
    font-family: 'Instrument Sans', 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.page {
    max-width: 860px;
    margin: 0 auto;
    padding: 56px 24px 80px;
}

.site-header {
    text-align: center;
    margin-bottom: 40px;
}

.brand {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin: 0 0 8px;
}

.tagline {
    margin: 0;
    color: var(--color-text-muted);
    font-size: 1.05rem;
}

.notice {
    border-radius: var(--radius);
    padding: 16px 20px;
    margin-bottom: 24px;
    border: 1px solid transparent;
    font-size: 0.95rem;
}

.notice p {
    margin: 0;
}

.notice p + p {
    margin-top: 6px;
}

.notice ul {
    margin: 8px 0 0;
    padding-left: 20px;
}

.notice--info {
    background: var(--color-info-bg);
    border-color: var(--color-info-border);
    color: var(--color-info-text);
}

.notice--success {
    background: #ecfdf5;
    border-color: #a7f3d0;
    color: #065f46;
}

.notice--error {
    background: var(--color-error-bg);
    border-color: var(--color-error-border);
    color: var(--color-error-text);
}

.notice__meta {
    opacity: 0.85;
    font-size: 0.88rem;
}

.workspace {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 32px;
}

.tts-form {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.field-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 10px;
}

.text-panel {
    display: flex;
    flex-direction: column;
}

.text-area {
    width: 100%;
    min-height: 320px;
    resize: vertical;
    padding: 18px 20px;
    font-size: 1.05rem;
    font-family: inherit;
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    outline: none;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.text-area:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.12);
}

.text-stats {
    display: flex;
    gap: 10px;
    margin-top: 10px;
    color: var(--color-text-muted);
    font-size: 0.88rem;
}

.settings-panel {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px;
    padding-top: 8px;
    border-top: 1px solid var(--color-border);
}

.field {
    display: flex;
    flex-direction: column;
}

.field-hint {
    margin: 8px 0 0;
    font-size: 0.82rem;
    color: var(--color-text-muted);
}

.select {
    appearance: none;
    padding: 12px 16px;
    font-size: 1rem;
    font-family: inherit;
    color: var(--color-text);
    background: var(--color-bg) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%236b7280' stroke-width='1.5' fill='none' fill-rule='evenodd'/%3E%3C/svg%3E") no-repeat right 16px center;
    border: 1px solid var(--color-border);
    border-radius: 10px;
    outline: none;
    cursor: pointer;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.12);
}

.speed-value {
    font-variant-numeric: tabular-nums;
    color: var(--color-primary);
    font-weight: 700;
}

.slider {
    width: 100%;
    accent-color: var(--color-primary);
    cursor: pointer;
}

.slider-scale {
    display: flex;
    justify-content: space-between;
    margin-top: 6px;
    color: var(--color-text-muted);
    font-size: 0.8rem;
}

.generate-button {
    grid-column: 1 / -1;
    justify-self: stretch;
    padding: 16px 24px;
    font-size: 1.05rem;
    font-weight: 700;
    font-family: inherit;
    color: #fff;
    background: var(--color-primary);
    border: none;
    border-radius: 12px;
    cursor: pointer;
    transition: background 0.15s ease, transform 0.05s ease;
}

.generate-button:hover {
    background: var(--color-primary-hover);
}

.generate-button:active {
    transform: translateY(1px);
}

@media (max-width: 640px) {
    .page {
        padding: 32px 16px 56px;
    }

    .brand {
        font-size: 2rem;
    }

    .workspace {
        padding: 20px;
    }

    .settings-panel {
        grid-template-columns: 1fr;
    }

    .text-area {
        min-height: 240px;
    }
}

.audio-result { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; margin-top: 14px; }
.audio-result audio { max-width: 100%; }
.download-button { padding: 9px 14px; color: #fff; background: var(--color-primary); border-radius: 8px; font-weight: 600; text-decoration: none; }
.generate-button:disabled { cursor: wait; opacity: .7; }