:root {
    --primary: #007AFF;
    --primary-hover: #0056b3;
    --bg-color: #f5f5f7;
    --card-bg: rgba(255, 255, 255, 0.7);
    --text-color: #1d1d1f;
    --text-secondary: #86868b;
    --border-color: rgba(0, 0, 0, 0.1);
    --glass-blur: 20px;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #000000;
        --card-bg: rgba(28, 28, 30, 0.7);
        --text-color: #f5f5f7;
        --text-secondary: #86868b;
        --border-color: rgba(255, 255, 255, 0.1);
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.5;
    overflow-x: hidden;
    transition: background-color 0.5s ease;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    background: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.app-icon {
    width: 32px;
    height: 32px;
    border-radius: 8px;
}

.app-header h1 {
    font-size: 1.25rem;
    font-weight: 600;
}

/* Main Layout */
.app-container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.glass {
    background: var(--card-bg);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--border-color);
    border-radius: 18px;
    box-shadow: var(--shadow-sm);
}

.card {
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Input Section */
textarea {
    width: 100%;
    min-height: 200px;
    padding: 1rem;
    border: none;
    background: transparent;
    color: var(--text-color);
    font-size: 1.1rem;
    resize: vertical;
    outline: none;
    font-family: inherit;
}

.input-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid var(--border-color);
    padding-top: 1rem;
}

#char-count {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* Buttons */
.primary-button {
    background: var(--primary);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 12px;
    font-weight: 600;
    font-size: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    transition: var(--transition);
}

.primary-button:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.3);
}

.primary-button:active {
    transform: translateY(0);
}

.icon-button {
    background: transparent;
    border: none;
    color: var(--text-color);
    padding: 0.5rem;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.icon-button:hover {
    background: var(--border-color);
}

/* Settings Sidebar */
.settings-sidebar {
    position: fixed;
    top: 0;
    right: -350px;
    width: 320px;
    height: 100vh;
    z-index: 200;
    padding: 2rem;
    transition: right 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    overflow-y: auto;
}

.settings-sidebar:not([inert]) {
    right: 0;
}

.settings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.setting-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.setting-group label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.setting-group input[type="text"],
.setting-group input[type="password"],
.setting-group select {
    padding: 0.75rem;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    background: rgba(0,0,0,0.05);
    color: var(--text-color);
    outline: none;
    font-family: inherit;
}

.setting-group.checkbox-group {
    flex-direction: row;
    align-items: center;
    gap: 0.75rem;
}

/* Results */
.audio-card {
    margin-bottom: 1rem;
    animation: slideIn 0.4s ease-out;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

audio {
    width: 100%;
    height: 40px;
    margin-top: 0.5rem;
}

/* Focus styles for accessibility */
:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Mobile Adjustments */
@media (max-width: 600px) {
    .app-header {
        padding: 0.75rem 1rem;
    }
    .settings-sidebar {
        width: 100%;
        right: -100%;
    }
}