/* ============================================================
   Pro Tuner — Premium Analog Aesthetic
   ============================================================ */

/* --- Custom Properties (Theme) --- */
:root {
    --bg: #1a1c20;
    --bg-noise: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
    --panel: #2a2d33;
    --panel-light: #32363e;
    --panel-dark: #22252a;
    --surface: #1e2025;
    --border: #3a3d44;
    --border-light: #4a4d55;
    --accent: #e8a838;
    --accent-dim: rgba(232, 168, 56, 0.15);
    --accent-glow: rgba(232, 168, 56, 0.4);
    --in-tune: #00c853;
    --in-tune-dim: rgba(0, 200, 83, 0.15);
    --in-tune-glow: rgba(0, 200, 83, 0.5);
    --off-tune: #ff7043;
    --off-tune-dim: rgba(255, 112, 67, 0.15);
    --text: #e8e6e1;
    --text-dim: #8a8d94;
    --text-muted: #5a5d64;
    --shadow: rgba(0, 0, 0, 0.4);
    --shadow-heavy: rgba(0, 0, 0, 0.6);
    --font-display: 'JetBrains Mono', 'Courier New', monospace;
    --font-ui: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    --radius: 12px;
    --radius-sm: 8px;
    --radius-xs: 4px;
    --transition: 0.2s ease;
    --transition-slow: 0.4s ease;
}

/* Light theme */
[data-theme="light"] {
    --bg: #eeecea;
    --panel: #ffffff;
    --panel-light: #f5f4f2;
    --panel-dark: #e8e6e2;
    --surface: #f0eeec;
    --border: #d4d2ce;
    --border-light: #c8c6c2;
    --accent: #c88a20;
    --accent-dim: rgba(200, 138, 32, 0.1);
    --accent-glow: rgba(200, 138, 32, 0.3);
    --in-tune: #00a844;
    --in-tune-dim: rgba(0, 168, 68, 0.1);
    --in-tune-glow: rgba(0, 168, 68, 0.3);
    --off-tune: #e05030;
    --off-tune-dim: rgba(224, 80, 48, 0.1);
    --text: #2a2825;
    --text-dim: #6a6864;
    --text-muted: #9a9894;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-heavy: rgba(0, 0, 0, 0.2);
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    -webkit-tap-highlight-color: transparent;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-ui);
    background: var(--bg);
    background-image: var(--bg-noise);
    color: var(--text);
    min-height: 100vh;
    min-height: 100dvh;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 20px;
    overflow-x: hidden;
}

/* --- App Container --- */
.app {
    width: 100%;
    max-width: 480px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    animation: fadeIn 0.6s ease both;
}

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

/* --- Header --- */
.header {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: 4px;
    padding: 8px 0;
    position: relative;
    animation: fadeIn 0.6s ease 0.05s both;
}

.header__title {
    width: 100%;
    text-align: center;
    font-family: var(--font-display);
    font-size: 1.4em;
    font-weight: 700;
    letter-spacing: 6px;
    color: var(--accent);
    text-shadow: 0 0 20px var(--accent-glow);
}

.header__subtitle {
    width: 100%;
    text-align: center;
    font-family: var(--font-display);
    font-size: 0.7em;
    font-weight: 400;
    letter-spacing: 3px;
    color: var(--text-dim);
    text-transform: uppercase;
}

.header__actions {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    gap: 4px;
}

/* --- Icon Buttons --- */
.btn-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: none;
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--text-dim);
    cursor: pointer;
    transition: all var(--transition);
}

.btn-icon:hover {
    background: var(--accent-dim);
    color: var(--accent);
}

.btn-icon:active {
    transform: scale(0.92);
}

/* --- Instrument & Tuning Selector --- */
.selector {
    display: flex;
    flex-direction: column;
    gap: 0;
    animation: fadeIn 0.6s ease 0.1s both;
}

.selector__toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    width: 100%;
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--text-muted);
    font-family: var(--font-ui);
    font-size: 0.72em;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    letter-spacing: 0.5px;
}

.selector__toggle:hover {
    color: var(--text-dim);
    border-color: var(--border-light);
}

.selector__toggle[aria-expanded="true"] svg {
    transform: rotate(180deg);
}

.selector__toggle svg {
    transition: transform var(--transition);
}

.selector__panel {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 8px;
    overflow: hidden;
    animation: slideDown 0.25s ease;
}

.selector__panel[hidden] {
    display: none;
}

.selector__instruments,
.selector__tunings {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    justify-content: center;
}

.selector__instruments button,
.selector__tunings button {
    padding: 7px 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--panel);
    color: var(--text-dim);
    font-family: var(--font-ui);
    font-size: 0.75em;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    letter-spacing: 0.5px;
    white-space: nowrap;
    min-height: 36px;
}

.selector__instruments button:hover,
.selector__tunings button:hover {
    border-color: var(--accent);
    color: var(--text);
    transform: translateY(-1px);
}

.selector__instruments button:active,
.selector__tunings button:active {
    transform: translateY(0);
}

.selector__instruments button.active,
.selector__tunings button.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #1a1c20;
    font-weight: 600;
    box-shadow: 0 0 12px var(--accent-glow);
}

/* --- Power Button --- */
.power-section {
    display: flex;
    justify-content: center;
    animation: fadeIn 0.6s ease 0.15s both;
}

.power-btn {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 32px;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    background: linear-gradient(180deg, var(--panel-light), var(--panel-dark));
    color: var(--text-dim);
    font-family: var(--font-display);
    font-size: 0.9em;
    font-weight: 600;
    letter-spacing: 3px;
    cursor: pointer;
    transition: all var(--transition);
    box-shadow: 0 4px 12px var(--shadow);
}

.power-btn:hover {
    border-color: var(--accent);
    color: var(--text);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px var(--shadow-heavy);
}

.power-btn:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px var(--shadow);
}

.power-btn.active {
    border-color: var(--in-tune);
    color: var(--in-tune);
    box-shadow: 0 0 20px var(--in-tune-glow), 0 4px 12px var(--shadow);
}

.power-btn.active svg {
    filter: drop-shadow(0 0 6px var(--in-tune-glow));
}

/* --- Note Display --- */
.note-display {
    text-align: center;
    padding: 24px 16px 20px;
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    box-shadow: inset 0 2px 8px var(--shadow);
    position: relative;
    animation: fadeIn 0.6s ease 0.2s both;
}

.note-display__note {
    font-family: var(--font-display);
    font-size: 4em;
    font-weight: 700;
    color: var(--accent);
    line-height: 1;
    letter-spacing: 4px;
    text-shadow: 0 0 20px var(--accent-glow);
    transition: color var(--transition);
    display: inline;
}

.note-display__octave {
    font-family: var(--font-display);
    font-size: 1.5em;
    font-weight: 400;
    color: var(--text-dim);
    display: inline;
    vertical-align: super;
    margin-left: 2px;
}

.note-display__frequency {
    font-family: var(--font-display);
    font-size: 0.9em;
    color: var(--text-dim);
    margin-top: 8px;
    letter-spacing: 1px;
}

.note-display__cents {
    font-family: var(--font-display);
    font-size: 1.1em;
    font-weight: 600;
    color: var(--text-muted);
    margin-top: 6px;
    letter-spacing: 1px;
    transition: color var(--transition);
}

.note-display__cents.in-tune {
    color: var(--in-tune);
    text-shadow: 0 0 10px var(--in-tune-glow);
}

.note-display__cents.off-tune {
    color: var(--off-tune);
}

/* In-tune pulsing glow */
.note-display.in-tune {
    border-color: var(--in-tune);
    box-shadow: inset 0 2px 8px var(--shadow), 0 0 20px var(--in-tune-dim);
}

.note-display.in-tune .note-display__note {
    color: var(--in-tune);
    text-shadow: 0 0 25px var(--in-tune-glow);
    animation: pulseGlow 1.5s ease-in-out infinite;
}

@keyframes pulseGlow {
    0%, 100% { text-shadow: 0 0 20px var(--in-tune-glow); }
    50% { text-shadow: 0 0 35px var(--in-tune-glow), 0 0 60px var(--in-tune-dim); }
}

/* --- Meter Section --- */
.meter-section {
    animation: fadeIn 0.6s ease 0.25s both;
}


.meter-container {
    width: 100%;
    height: 140px;
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    box-shadow: inset 0 2px 8px var(--shadow);
    overflow: hidden;
    position: relative;
}

.meter-container canvas {
    width: 100%;
    height: 100%;
    display: block;
}

/* --- Input Level --- */
.input-level {
    margin-top: 8px;
}

.input-level__bar {
    width: 100%;
    height: 4px;
    background: var(--surface);
    border-radius: 2px;
    overflow: hidden;
}

.input-level__fill {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--in-tune), var(--accent), var(--off-tune));
    border-radius: 2px;
    transition: width 0.08s ease-out;
}

.input-level__labels {
    display: flex;
    justify-content: space-between;
    margin-top: 3px;
    font-family: var(--font-display);
    font-size: 0.55em;
    color: var(--text-muted);
    letter-spacing: 1px;
}

@keyframes slideDown {
    from { opacity: 0; max-height: 0; }
    to { opacity: 1; max-height: 300px; }
}

/* --- String Cards --- */
.strings {
    animation: fadeIn 0.6s ease 0.35s both;
}

.strings__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(72px, 1fr));
    gap: 8px;
}

.string-card {
    padding: 14px 8px;
    background: linear-gradient(180deg, var(--panel-light), var(--panel));
    border-radius: var(--radius-sm);
    text-align: center;
    border: 1px solid var(--border);
    cursor: pointer;
    transition: all var(--transition);
    box-shadow: 0 2px 6px var(--shadow);
    position: relative;
    overflow: hidden;
    min-height: 48px;
}

.string-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: inherit;
    border: 2px solid transparent;
    transition: border-color var(--transition);
    pointer-events: none;
}

.string-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-heavy);
    border-color: var(--border-light);
}

.string-card:active {
    transform: translateY(0) scale(0.97);
}

.string-card.active {
    background: linear-gradient(180deg, var(--accent), #c88a20);
    border-color: var(--accent);
    box-shadow: 0 0 16px var(--accent-glow), 0 4px 12px var(--shadow-heavy);
    transform: scale(1.03);
}

.string-card.active::before {
    border-color: rgba(255, 255, 255, 0.2);
    animation: ringPulse 1.5s ease-in-out infinite;
}

@keyframes ringPulse {
    0%, 100% { border-color: rgba(255, 255, 255, 0.1); }
    50% { border-color: rgba(255, 255, 255, 0.3); }
}

.string-card.locked {
    border-color: var(--accent);
    box-shadow: 0 0 10px var(--accent-dim);
}

.string-card.locked::after {
    content: '';
    position: absolute;
    top: 4px;
    right: 4px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent);
}

.string-card__name {
    font-family: var(--font-ui);
    font-size: 0.6em;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 4px;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.string-card.active .string-card__name {
    color: rgba(26, 28, 32, 0.6);
}

.string-card__note {
    font-family: var(--font-display);
    font-size: 1.6em;
    font-weight: 700;
    color: var(--text);
    line-height: 1.1;
}

.string-card.active .string-card__note {
    color: #1a1c20;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

.string-card__freq {
    font-family: var(--font-display);
    font-size: 0.55em;
    color: var(--text-muted);
    margin-top: 3px;
    letter-spacing: 0.5px;
}

.string-card.active .string-card__freq {
    color: rgba(26, 28, 32, 0.5);
}

.strings__hint {
    text-align: center;
    margin-top: 8px;
    font-family: var(--font-ui);
    font-size: 0.7em;
    color: var(--text-muted);
    letter-spacing: 0.3px;
}

/* --- Status Bar --- */
.status-bar {
    text-align: center;
    padding: 10px 16px;
    background: var(--surface);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    animation: fadeIn 0.6s ease 0.4s both;
}

.status-bar__text {
    font-family: var(--font-display);
    font-size: 0.75em;
    color: var(--text-muted);
    letter-spacing: 1.5px;
    text-transform: uppercase;
}

.status-bar.active .status-bar__text {
    color: var(--in-tune);
    text-shadow: 0 0 8px var(--in-tune-dim);
}

.status-bar.listening .status-bar__text {
    color: var(--accent);
}

.status-bar.error .status-bar__text {
    color: var(--off-tune);
}

/* --- Settings Panel --- */
.settings-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 90;
    opacity: 0;
    transition: opacity var(--transition-slow);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}

.settings-overlay.visible {
    opacity: 1;
}

.settings-panel {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: 320px;
    max-width: 90vw;
    background: var(--panel);
    border-left: 1px solid var(--border);
    z-index: 100;
    transform: translateX(100%);
    transition: transform var(--transition-slow);
    overflow-y: auto;
    box-shadow: -4px 0 20px var(--shadow-heavy);
}

.settings-panel.visible {
    transform: translateX(0);
}

.settings-panel__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px;
    border-bottom: 1px solid var(--border);
}

.settings-panel__header h2 {
    font-family: var(--font-display);
    font-size: 1em;
    font-weight: 600;
    letter-spacing: 2px;
    color: var(--text);
}

.settings-panel__body {
    padding: 16px 20px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

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

.setting-label {
    font-family: var(--font-ui);
    font-size: 0.8em;
    font-weight: 500;
    color: var(--text-dim);
    letter-spacing: 0.3px;
}

/* A4 Reference */
.setting-a4 {
    display: flex;
    align-items: center;
    gap: 8px;
}

.setting-a4__btn {
    width: 36px;
    height: 36px;
    border: 1px solid var(--border);
    border-radius: var(--radius-xs);
    background: var(--surface);
    color: var(--text);
    font-size: 1.1em;
    cursor: pointer;
    transition: all var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.setting-a4__btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.setting-a4__input {
    width: 60px;
    height: 36px;
    border: 1px solid var(--border);
    border-radius: var(--radius-xs);
    background: var(--surface);
    color: var(--text);
    font-family: var(--font-display);
    font-size: 0.9em;
    text-align: center;
    outline: none;
    -moz-appearance: textfield;
}

.setting-a4__input::-webkit-inner-spin-button,
.setting-a4__input::-webkit-outer-spin-button {
    -webkit-appearance: none;
}

.setting-a4__input:focus {
    border-color: var(--accent);
}

.setting-a4__unit {
    font-family: var(--font-display);
    font-size: 0.8em;
    color: var(--text-muted);
}

/* Toggle Buttons */
.setting-toggle {
    display: flex;
    gap: 4px;
}

.setting-toggle__btn {
    flex: 1;
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-xs);
    background: transparent;
    color: var(--text-muted);
    font-family: var(--font-ui);
    font-size: 0.75em;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
}

.setting-toggle__btn:hover {
    border-color: var(--border-light);
    color: var(--text-dim);
}

.setting-toggle__btn.active {
    background: var(--accent-dim);
    border-color: var(--accent);
    color: var(--accent);
    font-weight: 600;
}

/* Select */
.setting-select select {
    width: 100%;
    height: 36px;
    padding: 0 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-xs);
    background: var(--surface);
    color: var(--text);
    font-family: var(--font-ui);
    font-size: 0.8em;
    cursor: pointer;
    outline: none;
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%238a8d94' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
}

.setting-select select:focus {
    border-color: var(--accent);
}

/* --- Responsive --- */
@media (max-width: 600px) {
    body {
        padding: 12px;
        align-items: flex-start;
    }

    .app {
        gap: 12px;
    }

    .header__title {
        font-size: 1.2em;
        letter-spacing: 4px;
    }

    .note-display {
        padding: 18px 12px 16px;
    }

    .note-display__note {
        font-size: 3.2em;
    }

    .meter-container {
        height: 120px;
    }

    .string-card {
        padding: 10px 6px;
    }

    .string-card__note {
        font-size: 1.4em;
    }

    .power-btn {
        padding: 10px 24px;
        font-size: 0.8em;
    }

    /* Settings as bottom sheet on mobile */
    .settings-panel {
        top: auto;
        right: 0;
        bottom: 0;
        left: 0;
        width: 100%;
        max-width: 100%;
        max-height: 85vh;
        border-left: none;
        border-top: 1px solid var(--border);
        border-radius: var(--radius) var(--radius) 0 0;
        transform: translateY(100%);
    }

    .settings-panel.visible {
        transform: translateY(0);
    }

}

/* --- Keyboard Focus Styles --- */
:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

button:focus:not(:focus-visible) {
    outline: none;
}

/* --- High Contrast Mode --- */
@media (prefers-contrast: high) {
    :root {
        --border: #666;
        --text-dim: #ccc;
        --text-muted: #999;
    }
}

/* --- Reduced Motion --- */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}