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

* {
    -webkit-tap-highlight-color: transparent !important;
    -webkit-touch-callout: none;
    user-select: none;
}

textarea, input[type="text"], input[type="number"], .pin {
    user-select: text;
    -webkit-user-select: text;
    -webkit-touch-callout: default;
}

html, body {
    -webkit-tap-highlight-color: transparent !important;
}

::selection {
    background: rgba(29, 155, 240, 0.3); /* A nice semi-transparent blue */
    color: var(--md-sys-color-on-surface);
}

:root {
    --md-sys-color-primary: #1D9BF0;
    --md-sys-color-on-primary: #FFFFFF;
    --md-sys-color-primary-container: #0F1419;
    --md-sys-color-on-primary-container: #E7E9EA;
    --md-sys-color-secondary: #0F1419;
    --md-sys-color-on-secondary: #E7E9EA;
    --md-sys-color-surface: #16181C;
    --md-sys-color-surface-variant: #202327;
    --md-sys-color-on-surface: #E7E9EA;
    --md-sys-color-on-surface-variant: #8E959B;
    --md-sys-color-outline: #2F3336;
    --md-sys-color-background: #000000;
    --md-sys-color-error: #F4212E;
    --md-sys-color-success: #00BA7C;
}

.dark {
    --md-sys-color-primary: #1D9BF0;
    --md-sys-color-on-primary: #FFFFFF;
    --md-sys-color-primary-container: #0F1419;
    --md-sys-color-on-primary-container: #E7E9EA;
    --md-sys-color-secondary: #0F1419;
    --md-sys-color-on-secondary: #E7E9EA;
    --md-sys-color-surface: #16181C;
    --md-sys-color-surface-variant: #202327;
    --md-sys-color-on-surface: #E7E9EA;
    --md-sys-color-on-surface-variant: #8E959B;
    --md-sys-color-outline: #2F3336;
    --md-sys-color-background: #000000;
    --md-sys-color-error: #F4212E;
    --md-sys-color-success: #00BA7C;
}

html {
    font-size: clamp(14px, 0.9vw, 18px);
}

body {
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background: var(--md-sys-color-background);
    color: var(--md-sys-color-on-surface);
    min-height: 100vh;
    transition: background 0.12s;
    line-height: 1.5;
}

.app-bar {
    background: var(--md-sys-color-background);
    padding: clamp(8px, 1.5vw, 12px) clamp(12px, 3vw, 48px);
    display: flex;
    align-items: center;
    gap: clamp(8px, 2vw, 16px);
    border-bottom: 1px solid var(--md-sys-color-outline);
    position: sticky;
    top: 0;
    z-index: 10;
}

.mode-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 200;
    padding: 24px;
}

.mode-modal {
    width: min(480px, 92vw);
    background: var(--md-sys-color-surface);
    border: 1px solid var(--md-sys-color-outline);
    border-radius: 20px;
    padding: 24px;
    text-align: center;
}

.mode-modal h2 {
    font-size: 20px;
    margin-bottom: 8px;
}

.mode-subtitle {
    color: var(--md-sys-color-on-surface-variant);
    margin-bottom: 20px;
}

.mode-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.lightbox {
    position: fixed;
    inset: 0;
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 300;
}

.lightbox.active {
    display: flex;
}

.lightbox-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.8);
}

.lightbox-content {
    position: relative;
    z-index: 1;
    width: min(920px, 92vw);
    max-height: 88vh;
    overflow: auto;
    background: var(--md-sys-color-surface);
    border: 1px solid var(--md-sys-color-outline);
    border-radius: 16px;
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.lightbox-close {
    align-self: flex-end;
    flex: none;
    width: 36px;
    height: 36px;
    min-width: 36px;
    min-height: 36px;
    padding: 0;
    border-radius: 8px;
    border: 1px solid var(--md-sys-color-outline);
    background: var(--md-sys-color-surface-variant);
    color: var(--md-sys-color-on-surface);
}

.lightbox-content img,
.lightbox-content video,
.lightbox-content iframe {
    width: 100%;
    max-height: 70vh;
    border-radius: 12px;
    border: 1px solid var(--md-sys-color-outline);
    background: #0B0F14;
}

.lightbox-content audio {
    width: 100%;
}

.lightbox-caption {
    color: var(--md-sys-color-on-surface-variant);
    font-size: 13px;
}

.mode-choice {
    border: 1px solid var(--md-sys-color-outline);
    background: transparent;
    color: var(--md-sys-color-on-surface);
    border-radius: 9999px;
    min-height: 44px;
    font-weight: 700;
}

.mode-choice:hover {
    background: var(--md-sys-color-surface-variant);
}

.app-bar h1 {
    font-size: clamp(16px, 1.2vw, 22px);
    font-weight: 700;
    flex: 1;
    color: var(--md-sys-color-on-surface);
}

.app-bar img {
    width: clamp(24px, 4vw, 32px) !important;
    height: clamp(24px, 4vw, 32px) !important;
}

.app-bar .material-icons {
    font-size: clamp(24px, 2vw, 28px);
    color: var(--md-sys-color-primary);
}

.container {
    max-width: clamp(320px, 90vw, 1440px);
    margin: clamp(16px, 2vw, 32px) auto;
    padding: 0 clamp(12px, 3vw, 48px) 88px;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 400px), 1fr));
    gap: clamp(16px, 2.5vw, 32px);
    justify-items: center;
}

.container.single {
    grid-template-columns: 1fr;
    justify-items: center;
}

.mode-toggle {
    position: fixed;
    bottom: clamp(16px, 2.5vw, 24px);
    left: 50%;
    transform: translateX(-50%);
    display: inline-flex;
    align-items: center;
    background: var(--md-sys-color-surface-variant);
    border: 1px solid var(--md-sys-color-outline);
    border-radius: 9999px;
    padding: 4px;
    gap: 4px;
    z-index: 100;
}

.mode-btn {
    flex: none;
    border-radius: 9999px;
    padding: 8px 16px;
    min-height: 36px;
    min-width: 96px;
    font-weight: 700;
    background: transparent;
    color: var(--md-sys-color-on-surface);
}

.mode-btn.active {
    background: var(--md-sys-color-primary);
    color: var(--md-sys-color-on-primary);
}

.card {
    background: var(--md-sys-color-surface);
    border-radius: clamp(12px, 1.5vw, 20px);
    padding: clamp(16px, 2vw, 32px);
    border: 1px solid var(--md-sys-color-outline);
    transition: border-color 0.12s;
    width: min(100%, 640px);
    justify-self: center;
}

.card:hover {
    border-color: #3A3F44;
}

.card h2 {
    font-size: clamp(18px, 1.3vw, 20px);
    font-weight: 500;
    margin-bottom: clamp(16px, 2vw, 24px);
    color: var(--md-sys-color-on-surface);
}

.input-container {
    margin-bottom: clamp(16px, 2vw, 24px);
}

.drop-zone {
    position: relative;
}

.drop-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(29, 155, 240, 0.1);
    border: 2px dashed var(--md-sys-color-primary);
    border-radius: clamp(8px, 1.5vw, 12px);
    display: none;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: clamp(8px, 1.5vw, 12px);
    pointer-events: none;
    z-index: 1;
}

.drop-overlay .material-icons {
    font-size: clamp(36px, 4vw, 48px);
    color: var(--md-sys-color-primary);
}

.drop-overlay p {
    font-size: clamp(14px, 1vw, 16px);
    font-weight: 500;
    color: var(--md-sys-color-on-primary-container);
}

.drop-zone.drag-over .drop-overlay {
    display: flex;
}

.size-indicator {
    font-size: clamp(11px, 0.8vw, 12px);
    color: var(--md-sys-color-on-surface-variant);
    margin-top: clamp(6px, 1vw, 8px);
    text-align: right;
}

.p2p-toggle {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 12px;
    font-size: clamp(12px, 0.85vw, 13px);
    color: var(--md-sys-color-on-surface-variant);
    cursor: pointer;
    user-select: none;
}

.p2p-toggle input[type="checkbox"] {
    width: 16px;
    height: 16px;
    padding: 0;
    margin: 0;
    flex: none;
    accent-color: var(--md-sys-color-primary);
    cursor: pointer;
}

textarea, input {
    width: 100%;
    padding: clamp(12px, 1.5vw, 16px);
    border: 1px solid var(--md-sys-color-outline);
    border-radius: clamp(8px, 1.2vw, 12px);
    font-family: inherit;
    font-size: clamp(13px, 0.9vw, 14px);
    background: var(--md-sys-color-background);
    color: var(--md-sys-color-on-surface);
    transition: border-color 0.12s, box-shadow 0.12s;
    line-height: 1.4;
}

textarea {
    min-height: clamp(100px, 12vw, 140px);
    resize: vertical;
}

textarea:focus, input:focus {
    outline: none;
    border-color: var(--md-sys-color-primary);
    box-shadow: 0 0 0 2px rgba(29, 155, 240, 0.3);
}

textarea::placeholder, input::placeholder {
    color: var(--md-sys-color-on-surface-variant);
}

.button-group {
    display: flex;
    gap: clamp(8px, 1.5vw, 12px);
    margin-bottom: clamp(16px, 2vw, 24px);
    flex-wrap: wrap;
}

button {
    flex: 1;
    min-width: clamp(100px, 18vw, 120px);
    min-height: clamp(40px, 4vw, 48px);
    padding: clamp(10px, 1.2vw, 12px) clamp(16px, 2vw, 24px);
    border: none;
    border-radius: 9999px;
    font-size: clamp(12px, 0.9vw, 13px);
    font-weight: 700;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: clamp(6px, 1vw, 8px);
    transition: all 0.12s;
    text-transform: none;
    letter-spacing: 0;
}

.btn-primary {
    background: var(--md-sys-color-primary);
    color: var(--md-sys-color-on-primary);
}

.btn-primary:hover:not(:disabled) {
    filter: brightness(1.05);
}

.btn-primary:active {
    filter: brightness(0.95);
}

.btn-secondary {
    background: transparent;
    color: var(--md-sys-color-on-surface);
    border: 1px solid var(--md-sys-color-outline);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--md-sys-color-surface-variant);
}

button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.qr-container {
    display: flex;
    justify-content: center;
    margin-bottom: 16px;
}

.qr-box {
    background: #ffffff;
    padding: 10px;
    border-radius: 10px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.qr-box svg {
    width: 150px;
    height: 150px;
    display: block;
}

.pin {
    font-size: clamp(36px, 3vw, 56px);
    font-weight: 800;
    text-align: center;
    margin: clamp(16px, 2vw, 24px) 0;
    color: var(--md-sys-color-primary);
    letter-spacing: clamp(8px, 1.5vw, 16px);
    font-family: 'Courier New', monospace;
    user-select: all;
}

.msg {
    text-align: center;
    padding: clamp(10px, 1.2vw, 12px) clamp(12px, 1.8vw, 16px);
    margin-top: clamp(8px, 1.2vw, 12px);
    border-radius: clamp(8px, 1.2vw, 12px);
    font-size: clamp(13px, 0.9vw, 14px);
    border: 1px solid transparent;
}


.success {
    background: rgba(0, 186, 124, 0.15);
    color: var(--md-sys-color-success);
    border-color: rgba(0, 186, 124, 0.35);
}

.error {
    background: rgba(244, 33, 46, 0.12);
    color: var(--md-sys-color-error);
    border-color: rgba(244, 33, 46, 0.35);
}

.file-list-item {
    display: flex;
    align-items: center;
    gap: clamp(8px, 1.5vw, 12px);
    padding: clamp(8px, 1.2vw, 12px);
    margin-top: clamp(6px, 1vw, 8px);
    background: var(--md-sys-color-surface-variant);
    border-radius: 12px;
    position: relative;
    border: 1px solid var(--md-sys-color-outline);
}

.file-list-item--preview {
    align-items: flex-start;
}

.file-preview-media {
    width: 96px;
    height: 96px;
    border-radius: 10px;
    object-fit: cover;
    background: #0B0F14;
    border: 1px solid var(--md-sys-color-outline);
    flex-shrink: 0;
}

.preview-wrapper {
    position: relative;
    width: 96px;
    height: 96px;
    flex-shrink: 0;
}

.preview-wrapper--audio {
    width: min(200px, 55vw);
    height: 44px;
}

.file-preview-audio {
    width: 100%;
    height: 44px;
    border-radius: 10px;
}

.preview-trigger,
.preview-expand {
    cursor: pointer;
}

.preview-expand {
    position: absolute;
    top: 6px;
    right: 6px;
    flex: none;
    width: 28px;
    height: 28px;
    min-width: 28px;
    min-height: 28px;
    border-radius: 6px;
    padding: 0;
    background: rgba(15, 20, 25, 0.8);
    color: #E7E9EA;
    border: 1px solid var(--md-sys-color-outline);
}

.preview-expand .material-icons {
    font-size: 16px;
}

.file-preview-pdf {
    width: 96px;
    height: 96px;
    border-radius: 10px;
}

.file-list-item:focus-within {
    outline: 2px solid var(--md-sys-color-primary);
    outline-offset: 2px;
}

.file-icon {
    font-size: clamp(40px, 4vw, 48px);
    color: var(--md-sys-color-primary);
    flex-shrink: 0;
}

.file-name {
    flex: 1;
    min-width: 0;
    font-size: clamp(13px, 0.9vw, 14px);
    color: var(--md-sys-color-on-surface-variant);
    word-break: break-word;
    overflow: hidden;
    text-overflow: ellipsis;
}

.remove-btn, .download-single-btn {
    width: clamp(32px, 4vw, 36px);
    height: clamp(32px, 4vw, 36px);
    min-width: clamp(32px, 4vw, 36px);
    min-height: clamp(32px, 4vw, 36px);
    padding: clamp(5px, 0.8vw, 6px);
    border-radius: 8px;
    background: var(--md-sys-color-error);
    color: white;
    flex: none;
    position: static;
}

.download-single-btn {
    background: var(--md-sys-color-primary);
}

.remove-btn:hover:not(:disabled), .download-single-btn:hover:not(:disabled) {
    opacity: 0.9;
    transform: scale(1.05);
}

.remove-btn:focus, .download-single-btn:focus {
    outline: 2px solid var(--md-sys-color-primary);
    outline-offset: 2px;
}

.remove-btn .material-icons, .download-single-btn .material-icons {
    font-size: clamp(18px, 2vw, 20px);
}

.file-size {
    font-size: clamp(10px, 0.75vw, 11px);
    color: var(--md-sys-color-on-surface-variant);
    opacity: 0.7;
}

.loading-spinner {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.retry-msg {
    display: flex;
    align-items: center;
    gap: clamp(6px, 1vw, 8px);
    justify-content: center;
}

.retry-msg .material-icons {
    font-size: clamp(16px, 1.5vw, 18px);
    animation: spin 1s linear infinite;
}

@media (max-width: 768px) {
    .container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    .app-bar {
        padding: 8px 12px;
        gap: 8px;
    }

    .app-bar h1 {
        font-size: 16px;
    }

    .container {
        margin: 10px auto;
        padding: 0 10px 76px;
        gap: 12px;
    }

    .card {
        padding: 14px;
        border-radius: 14px;
    }

    .card h2 {
        font-size: 16px;
        margin-bottom: 12px;
    }

    .input-container {
        margin-bottom: 12px;
    }

    textarea, input {
        padding: 10px 12px;
        border-radius: 10px;
    }

    textarea {
        min-height: 96px;
    }

    .button-group {
        gap: 8px;
        margin-bottom: 12px;
    }

    .button-group button {
        min-width: 0;
        min-height: 40px;
        padding: 8px 12px;
        flex: 1 1 auto;
    }

    .file-list-item {
        padding: 8px;
        gap: 10px;
        border-radius: 10px;
    }

    .file-list-item--preview {
        align-items: center;
    }

    .file-preview-media,
    .preview-wrapper,
    .file-preview-pdf {
        width: 56px;
        height: 56px;
        border-radius: 8px;
    }

    .preview-wrapper--audio {
        width: min(170px, 50vw);
        height: 40px;
    }

    .file-preview-audio {
        height: 40px;
    }

    .preview-expand {
        top: 4px;
        right: 4px;
        width: 24px;
        height: 24px;
        min-width: 24px;
        min-height: 24px;
    }

    .preview-expand .material-icons {
        font-size: 14px;
    }

    .pin {
        font-size: 32px;
        letter-spacing: 8px;
        margin: 10px 0;
    }

    .qr-container {
        margin-bottom: 10px;
    }

    .qr-box {
        padding: 8px;
    }

    .qr-box svg {
        width: 128px;
        height: 128px;
    }

    .msg {
        padding: 8px 10px;
        font-size: 12.5px;
    }

    .mode-toggle {
        bottom: 12px;
    }

    .mode-btn {
        min-width: 84px;
        min-height: 34px;
        padding: 6px 14px;
        font-size: 13px;
    }

    .mode-modal {
        padding: 18px;
        border-radius: 16px;
    }
}

@media (min-width: 1400px) {
    .container {
        max-width: clamp(1200px, 85vw, 1600px);
    }
}