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

a {
    text-decoration: none;
}

ul, ol, li {
    list-style: none;
}

html,
body {
    height: 100%;
    line-height: 1.5;
    font-size: 16px;
}

img, picture, video, canvas, svg {
    vertical-align: top;
}

input, button, textarea, select {
    font: inherit;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: inherit;
    font-size: inherit;
}

/* ==================== Font Import ==================== */
@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&family=DM+Sans:wght@400;500&family=JetBrains+Mono:wght@500&display=swap');

/* ==================== Design System Variables ==================== */
:root {
    /* brand colors - teal/cyan focused */
    --color-accent: #14b8a6;
    --color-accent-hover: #0d9488;
    --color-accent-glow: rgba(20, 184, 166, 0.4);
    --color-accent-light: rgba(20, 184, 166, 0.15);
    --color-accent-alpha: rgba(20, 184, 166, 0.2);

    /* semantic colors */
    --color-success: #10b981;
    --color-success-glow: rgba(16, 185, 129, 0.3);
    --color-error: #f43f5e;
    --color-error-glow: rgba(244, 63, 94, 0.3);
    --color-warning: #f59e0b;

    /* dark theme (default) */
    --color-background: #0a0e17;
    --color-background-subtle: #0f1420;
    --color-surface: #1a2538;
    --color-surface-elevated: #212d45;
    --color-surface-hover: #1f2942;
    --color-text-primary: #f1f5f9;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;
    --color-border: #1e293b;
    --color-border-subtle: #334155;
    --color-input-bg: #1e2d42;
    --color-input-border: #334155;
    --color-input-focus: var(--color-accent);

    /* glass effect */
    --glass-bg: rgba(30, 42, 62, 0.85);
    --glass-border: rgba(255, 255, 255, 0.06);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);

    /* spacing - 8px grid */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;
    --spacing-3xl: 64px;
    --spacing-4xl: 80px;
    --spacing-5xl: 96px;

    /* typography */
    --font-display: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-body: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'SF Mono', monospace;

    /* font sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 2rem;
    --text-4xl: 2.5rem;

    /* font weights */
    --font-normal: 400;
    --font-medium: 500;
    --font-semibold: 600;
    --font-bold: 700;
    --font-extrabold: 800;

    /* shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.6);
    --shadow-glow: 0 0 40px var(--color-accent-glow);

    /* transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);

    /* border radius */
    --radius-xs: 4px;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-xl: 20px;
    --radius-2xl: 28px;
}

/* ==================== Base Styles ==================== */
body {
    background: var(--color-background);
    color: var(--color-text-primary);
    font-family: var(--font-body);
    font-size: var(--text-base);
    font-weight: var(--font-normal);
    line-height: 1.6;
    min-width: 320px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    position: relative;
}

/* subtle grid pattern background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        radial-gradient(circle at 25% 25%, rgba(20, 184, 166, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 75% 75%, rgba(99, 102, 241, 0.03) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

/* noise texture overlay */
body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
    opacity: 0.015;
    pointer-events: none;
    z-index: -1;
}

/* ==================== Typography ==================== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: var(--font-bold);
    line-height: 1.2;
    margin: 0;
    letter-spacing: -0.02em;
    color: var(--color-text-primary);
}

h1 {
    font-size: var(--text-4xl);
    font-weight: var(--font-extrabold);
    letter-spacing: -0.03em;
}

h2 {
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
}

h3 {
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
}

p {
    font-size: var(--text-base);
    line-height: 1.7;
    color: var(--color-text-secondary);
    margin: 0 0 var(--spacing-md) 0;
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

label {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-family: var(--font-display);
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.01em;
}

.input-icon {
    color: var(--color-accent);
    flex-shrink: 0;
    opacity: 0.8;
}

/* ==================== Form Controls ==================== */
textarea,
input[type=text],
input[type=number],
input[type=password],
select {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: var(--text-base);
    font-family: var(--font-body);
    font-weight: var(--font-normal);
    background: var(--color-input-bg);
    color: var(--color-text-primary);
    border: 1px solid var(--color-input-border);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    outline: none;
}

textarea {
    min-height: 140px;
    resize: vertical;
    line-height: 1.6;
}

input:focus,
textarea:focus,
select:focus {
    background: var(--color-surface);
    border-color: var(--color-accent);
    outline: none;
    box-shadow: none;
}

input::placeholder,
textarea::placeholder {
    color: var(--color-text-muted);
}

/* error state for inputs */
input.error-input,
textarea.error-input,
select.error-input {
    border-color: var(--color-error);
    box-shadow: 0 0 0 3px var(--color-error-glow);
}

/* pin input - distinctive monospace styling */
input.pin-input {
    font-family: var(--font-mono);
    font-size: var(--text-base);
    font-weight: var(--font-medium);
    letter-spacing: 0.3em;
    text-align: center;
    max-width: 200px;
    padding: var(--spacing-md) var(--spacing-lg);
}

/* number input */
input[type="number"] {
    -webkit-appearance: textfield;
    -moz-appearance: textfield;
    appearance: textfield;
}

input[type=number]::-webkit-inner-spin-button,
input[type=number]::-webkit-outer-spin-button {
    -webkit-appearance: none;
}

/* select dropdown */
select {
    cursor: pointer;
    padding-right: 44px;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='%2394a3b8' d='M6 8L0 0h12z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
}

/* ==================== Buttons ==================== */
.main-btn,
button[type="submit"] {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-family: var(--font-display);
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    color: #ffffff;
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-hover) 100%);
    border: none;
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 56px;
    width: 100%;
    letter-spacing: -0.01em;
    box-shadow: 0 4px 14px var(--color-accent-glow), var(--shadow-md);
    position: relative;
    overflow: hidden;
}

.main-btn::before,
button[type="submit"]::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s ease;
}

.main-btn:hover::before,
button[type="submit"]:hover::before {
    left: 100%;
}

.btn-icon {
    flex-shrink: 0;
}

.button-text {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.main-btn:hover,
button[type="submit"]:hover {
    filter: brightness(1.1);
    box-shadow: 0 6px 20px var(--color-accent-glow);
}

a.main-btn {
    color: #ffffff;
    text-decoration: none;
}

a.main-btn:hover {
    color: #ffffff;
}

.main-btn:active,
button[type="submit"]:active {
    filter: brightness(0.95);
}

.main-btn:disabled,
button[type="submit"]:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.second-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    font-family: var(--font-display);
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    color: var(--color-accent);
    background: transparent;
    border: 2px solid var(--color-accent);
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 52px;
    width: 100%;
    text-decoration: none;
}

.second-btn:hover {
    background: var(--color-accent-light);
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.main-btn-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-family: var(--font-display);
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    color: #ffffff;
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-hover) 100%);
    border-radius: var(--radius-xl);
    text-decoration: none;
    transition: all var(--transition-fast);
    min-height: 56px;
    width: 100%;
    box-shadow: 0 4px 14px var(--color-accent-glow);
}

.main-btn-link:hover {
    color: #ffffff;
    filter: brightness(1.1);
    box-shadow: 0 6px 20px var(--color-accent-glow);
}

/* ==================== App Layout ==================== */
.app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--spacing-2xl) var(--spacing-lg) var(--spacing-xl);
}

.app-container {
    width: 100%;
    max-width: 560px;
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.logo-title {
    text-align: center;
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-md) 0;
}

.logo-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-md);
    text-decoration: none;
    color: var(--color-text-primary);
    transition: all var(--transition-fast);
}

.logo-link:hover {
    transform: scale(1.02);
    color: var(--color-text-primary);
}

.app-name {
    font-family: var(--font-display);
    font-size: var(--text-3xl);
    font-weight: var(--font-extrabold);
    letter-spacing: -0.03em;
    color: var(--color-accent);
    transition: color var(--transition-fast);
}

.logo-link:hover .app-name {
    color: var(--color-accent-hover);
}

.logo-icon {
    color: var(--color-accent);
    transition: color var(--transition-fast);
}

.logo-link:hover .logo-icon {
    color: var(--color-accent-hover);
}

.main-content {
    flex: 1;
    animation: fadeInUp 0.5s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==================== Cards ==================== */
.card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--radius-2xl);
    box-shadow: var(--glass-shadow);
    border: 1px solid var(--glass-border);
    padding: var(--spacing-xl) var(--spacing-2xl) var(--spacing-2xl);
    margin-bottom: var(--spacing-xl);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

/* subtle accent glow on cards */
.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--color-accent-alpha), transparent);
}

.card:hover {
    box-shadow: var(--shadow-xl), 0 0 60px rgba(20, 184, 166, 0.05);
    border-color: rgba(255, 255, 255, 0.08);
}

.card-header {
    margin-bottom: var(--spacing-xl);
}

.card-title-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.card-title-row .card-title {
    margin-bottom: 0;
}

.card-title {
    font-family: var(--font-display);
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.02em;
}

.card-description {
    font-size: var(--text-base);
    color: var(--color-text-secondary);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

/* Mode Toggle (Text/File selector) */
.mode-toggle {
    display: flex;
    background: var(--color-surface);
    border: 1px solid var(--color-border-subtle);
    border-radius: var(--radius-md);
    padding: 3px;
    flex-shrink: 0;
}

.mode-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    font-family: var(--font-display);
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    color: var(--color-text-muted);
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.mode-btn:hover {
    color: var(--color-text-secondary);
}

.mode-btn.active {
    background: var(--color-accent);
    color: var(--color-background);
    box-shadow: 0 2px 8px var(--color-accent-glow);
}

.card-title-with-icon {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.title-icon {
    color: var(--color-success);
    flex-shrink: 0;
}

/* ==================== Form Groups ==================== */
.form-group {
    margin-bottom: var(--spacing-xl);
}

.form-row {
    display: grid;
    gap: var(--spacing-lg);
}

.form-row:not(:last-child) {
    margin-bottom: var(--spacing-xl);
}

@media (min-width: 640px) {
    .form-row.two-cols {
        grid-template-columns: 1fr 1fr;
    }
    .form-row.three-cols {
        grid-template-columns: 1fr 1fr 1fr;
    }
}

.expire-container {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-md);
    align-items: end;
}

/* ==================== Messages & Alerts ==================== */
.error {
    font-family: var(--font-display);
    color: var(--color-error);
    font-size: var(--text-lg);
    font-weight: var(--font-semibold);
    margin-top: var(--spacing-sm);
    animation: shake 0.4s ease;
    text-align: center;
    display: block;
}

.optional-hint {
    color: var(--color-text-muted);
    font-weight: var(--font-normal);
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    20%, 60% { transform: translateX(-6px); }
    40%, 80% { transform: translateX(6px); }
}

.success {
    font-family: var(--font-display);
    color: var(--color-success);
    font-size: var(--text-lg);
    font-weight: var(--font-semibold);
    margin-top: var(--spacing-sm);
    animation: fadeIn 0.3s ease;
    text-align: center;
    display: block;
}

.error-block {
    background: rgba(244, 63, 94, 0.1);
    border: 1px solid rgba(244, 63, 94, 0.3);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    color: var(--color-error);
}

.success-message {
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.3);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    color: var(--color-success);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-4px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ==================== Tooltip ==================== */
.tooltip {
    position: relative;
    display: inline-block;
}

.tooltip-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    color: var(--color-text-muted);
    cursor: help;
    margin-left: var(--spacing-xs);
    transition: color var(--transition-fast);
}

.tooltip:hover .tooltip-icon {
    color: var(--color-accent);
}

.tooltip-text {
    visibility: hidden;
    opacity: 0;
    position: absolute;
    z-index: 1000;
    bottom: 130%;
    left: 50%;
    transform: translateX(-50%) translateY(4px);
    background: var(--color-surface-elevated);
    color: var(--color-text-primary);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    font-family: var(--font-body);
    font-weight: var(--font-medium);
    white-space: nowrap;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    transition: all var(--transition-fast);
}

.tooltip-text::after {
    content: "";
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border-width: 6px;
    border-style: solid;
    border-color: var(--color-surface-elevated) transparent transparent transparent;
}

.tooltip:hover .tooltip-text {
    visibility: visible;
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ==================== Steps (About Page) ==================== */
.how-it-works-container {
    margin: var(--spacing-2xl) 0;
}

.how-it-works-container h1 {
    font-family: var(--font-display);
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    color: var(--color-text-primary);
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.steps-container {
    display: grid;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-2xl);
}

.step-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    border: 1px solid var(--color-border);
    transition: all var(--transition-fast);
}

.step-card:hover {
    background: var(--color-surface-hover);
    border-color: var(--color-border-subtle);
    transform: translateX(8px);
}

.circle {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--color-accent), var(--color-accent-hover));
    color: var(--color-background);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-weight: var(--font-bold);
    font-size: var(--text-lg);
    box-shadow: 0 4px 12px var(--color-accent-glow);
}

.step-text {
    flex: 1;
}

.step-text p {
    margin: 0;
    color: var(--color-text-secondary);
    font-size: var(--text-base);
}

/* ==================== App Footer ==================== */
.app-footer {
    text-align: center;
    padding-top: var(--spacing-xl);
    margin-top: var(--spacing-xl);
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    border-top: 1px solid var(--color-border);
}

.copyright {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

.footer-link {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    text-decoration: none;
    transition: color var(--transition-fast);
    font-weight: var(--font-medium);
}

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

.separator {
    color: var(--color-text-muted);
    opacity: 0.3;
    font-size: var(--text-xs);
}

/* ==================== Popup/Modal ==================== */
.popup {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.popup.active {
    opacity: 1;
    visibility: visible;
}

.popup-content {
    background: var(--color-surface);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-2xl);
    width: 90%;
    max-width: 420px;
    max-height: 80vh;
    overflow: auto;
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--color-border);
    transform: scale(0.9) translateY(20px);
    transition: transform var(--transition-bounce);
    position: relative;
    text-align: center;
}

.popup.active .popup-content {
    transform: scale(1) translateY(0);
}

.popup-header {
    display: flex;
    justify-content: flex-end;
    align-items: flex-start;
    margin-bottom: var(--spacing-md);
    position: absolute;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
}

.popup-text {
    font-size: var(--text-lg);
    line-height: 1.6;
    color: var(--color-text-primary);
    margin-top: var(--spacing-md);
}

.popup-text strong {
    display: block;
    font-size: var(--text-xl);
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-primary);
}

.close-popup {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--color-surface-hover);
    border: 1px solid var(--color-border);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    color: var(--color-text-muted);
}

.close-popup:hover {
    background: var(--color-error);
    border-color: var(--color-error);
    color: white;
    transform: scale(1.1);
}

.close-popup img {
    width: 16px;
    height: 16px;
    filter: invert(0.6);
}

.close-popup:hover img {
    filter: invert(1);
}

/* No-PIN confirmation modal */
.no-pin-modal-content {
    max-width: 480px;
    text-align: center;
}

.no-pin-title {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    font-family: var(--font-display);
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-lg);
}

.no-pin-title svg {
    color: var(--color-primary);
    flex-shrink: 0;
}

.no-pin-description {
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.no-pin-hint {
    font-size: var(--text-sm);
    line-height: 1.5;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-xl);
}

.no-pin-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
}

.no-pin-actions .second-btn,
.no-pin-actions .main-btn {
    flex: 1;
    max-width: 160px;
    white-space: nowrap;
}

/* Form popups (login, email) */
.login-popup,
.email-popup {
    text-align: left;
}

.login-popup .popup-header,
.email-popup .popup-header {
    position: relative;
    top: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.popup-title {
    font-family: var(--font-display);
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
    color: var(--color-text-primary);
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.login-form .form-field {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.login-form .form-field label {
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: var(--color-text-secondary);
}

.login-form .form-field input {
    padding: var(--spacing-md) var(--spacing-lg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    font-size: var(--text-base);
    background: var(--color-input-bg);
    color: var(--color-text-primary);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.login-form .form-field input:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px var(--color-accent-alpha);
}

.login-form .form-error {
    padding: var(--spacing-sm) var(--spacing-md);
    background: rgba(244, 63, 94, 0.1);
    border: 1px solid rgba(244, 63, 94, 0.3);
    border-radius: var(--radius-md);
    color: var(--color-error);
    font-size: var(--text-sm);
}

/* Email popup */
.email-popup {
    max-width: 500px;
    width: 90vw;
}

.email-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.email-form .form-field {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.email-form .form-field label {
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: var(--color-text-secondary);
}

.email-form .form-field label .optional {
    font-weight: var(--font-normal);
    color: var(--color-text-muted);
}

.email-form .form-field input {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--text-base);
    background: var(--color-input-bg);
    color: var(--color-text-primary);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.email-form .form-field input:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px var(--color-accent-alpha);
}

.email-form .form-error {
    padding: var(--spacing-sm) var(--spacing-md);
    background: rgba(244, 63, 94, 0.1);
    border: 1px solid rgba(244, 63, 94, 0.3);
    border-radius: var(--radius-md);
    color: var(--color-error);
    font-size: var(--text-sm);
}

.email-preview-container {
    margin-top: var(--spacing-sm);
}

.email-preview {
    padding: var(--spacing-md);
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    max-height: 150px;
    overflow-y: auto;
    line-height: 1.5;
}

.form-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: flex-end;
    margin-top: var(--spacing-md);
}

.form-actions .btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.form-actions .btn-primary {
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-dark) 100%);
    color: white;
    border: none;
}

.form-actions .btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--color-accent-alpha);
}

.form-actions .btn-secondary {
    background: transparent;
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
}

.form-actions .btn-secondary:hover {
    border-color: var(--color-text-secondary);
    color: var(--color-text-primary);
}

/* Email sent success */
.email-sent-success {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
}

.email-sent-success .success-icon {
    color: var(--color-success);
}

.email-sent-success strong {
    font-size: var(--text-lg);
    color: var(--color-text-primary);
}

.email-sent-success span {
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
}

/* ==================== Specific Pages ==================== */
.show-msg {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 50vh;
}

.load-msg-form {
    width: 100%;
    max-width: 400px;
    margin: 0 auto;
    text-align: center;
}

.load-msg-form .card-header {
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

.load-msg-form .card-title {
    font-size: var(--text-2xl);
    margin-bottom: var(--spacing-sm);
}

.load-msg-form .card-description {
    font-size: var(--text-base);
}

.load-msg-form .form-group {
    margin-bottom: var(--spacing-xl);
}

.load-msg-form .form-group label {
    text-align: center;
    margin-bottom: var(--spacing-md);
    font-size: var(--text-base);
    font-weight: var(--font-medium);
    justify-content: center;
}

.load-msg-form .pin-input {
    margin: 0 auto;
    display: block;
    max-width: 280px;
}

.msg-link-text {
    margin: var(--spacing-lg) 0;
}

.error-page {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 50vh;
    padding: var(--spacing-xl);
}

.error-card {
    width: 100%;
    max-width: 480px;
    margin: 0 auto;
    text-align: center;
    background: var(--color-surface);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-3xl) var(--spacing-xl);
}

.error-message {
    font-family: var(--font-display);
    font-size: var(--text-lg);
    color: var(--color-error);
    margin-bottom: var(--spacing-2xl);
    line-height: 1.6;
    font-weight: var(--font-semibold);
    text-align: center;
}

/* ==================== Content Input Area ==================== */
#content-input .form-group {
    margin-bottom: var(--spacing-lg);
}

.content-input-area {
    height: 140px;
}

textarea.content-input-area {
    resize: none;
    min-height: unset;
    display: block;
}

.drop-zone.content-input-area {
    padding: var(--spacing-lg);
}

/* ==================== File Upload Drop Zone ==================== */
.drop-zone {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl);
    border: 2px dashed var(--color-border-subtle);
    border-radius: var(--radius-xl);
    background: var(--color-surface);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.drop-zone:hover {
    border-color: var(--color-accent);
    background: var(--color-surface-hover);
    box-shadow: 0 0 30px var(--color-accent-alpha);
}

.drop-zone.drag-over {
    border-color: var(--color-accent);
    background: var(--color-accent-light);
    box-shadow: var(--shadow-glow);
}

.drop-zone svg {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
    transition: color var(--transition-fast);
}

.drop-zone:hover svg {
    color: var(--color-accent);
}

.drop-zone p {
    margin: 0;
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
}

.drop-zone .file-info {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-accent-light);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    color: var(--color-accent);
    font-weight: var(--font-semibold);
}

.drop-zone .file-info.error {
    color: var(--color-error);
    background: rgba(244, 63, 94, 0.1);
}

.drop-zone.error-input {
    border-color: var(--color-error);
    background: rgba(244, 63, 94, 0.05);
}

/* ==================== File Info Box (Secure Link) ==================== */
.file-info-box {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-accent-light);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-xl);
    border: 1px solid var(--color-accent-alpha);
}

.file-info-box svg {
    flex-shrink: 0;
    color: var(--color-accent);
}

.file-details {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.file-name {
    font-weight: var(--font-semibold);
    color: var(--color-text-primary);
    word-break: break-all;
}

.file-size {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}

/* ==================== Responsive ==================== */
@media (max-width: 768px) {
    .app {
        padding: var(--spacing-lg) var(--spacing-md) var(--spacing-md);
    }

    .app-container {
        gap: var(--spacing-lg);
    }

    .card {
        padding: var(--spacing-xl);
        border-radius: var(--radius-xl);
    }

    .expire-container {
        grid-template-columns: 1fr;
    }

    .step-card {
        padding: var(--spacing-md);
    }

    .app-name {
        font-size: var(--text-2xl);
    }

    .card-title {
        font-size: var(--text-xl);
    }

    .theme-toggle {
        top: var(--spacing-md);
        right: var(--spacing-md);
        width: 44px;
        height: 44px;
    }

    .app-footer .separator {
        display: none;
    }

    .app-footer {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    .popup-content {
        width: 95%;
        padding: var(--spacing-xl);
    }

    input.pin-input {
        max-width: 200px;
        font-size: var(--text-lg);
        letter-spacing: 0.25em;
    }

    .app-name {
        font-size: var(--text-xl);
    }

    .main-btn,
    button[type="submit"] {
        min-height: 52px;
        padding: var(--spacing-md) var(--spacing-lg);
    }
}

/* ==================== Loading States ==================== */
.loading {
    position: relative;
    pointer-events: none;
    opacity: 0.6;
}

.loading::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 24px;
    height: 24px;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-accent);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

/* htmx loading indicators */
.htmx-indicator {
    display: none;
    align-items: center;
    gap: var(--spacing-sm);
}

.htmx-request .htmx-indicator {
    display: inline-flex;
}

.htmx-request .button-text {
    display: none;
}

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

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

/* smooth transitions for htmx swaps */
.htmx-swapping {
    opacity: 0;
    transition: opacity 150ms ease-out;
}

.htmx-settling {
    opacity: 1;
    transition: opacity 150ms ease-in;
}

/* ==================== Toast Notifications ==================== */
.toast-container {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: 1000;
    pointer-events: none;
}

.toast {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    box-shadow: var(--shadow-xl);
    animation: slideIn 0.3s ease-out;
    pointer-events: auto;
    min-width: 300px;
    max-width: 500px;
    backdrop-filter: blur(20px);
}

.toast.success {
    border-color: var(--color-success);
    background: linear-gradient(135deg, var(--color-surface) 0%, rgba(16, 185, 129, 0.1) 100%);
}

.toast.error {
    border-color: var(--color-error);
    background: linear-gradient(135deg, var(--color-surface) 0%, rgba(244, 63, 94, 0.1) 100%);
}

.toast.warning {
    border-color: var(--color-warning);
    background: linear-gradient(135deg, var(--color-surface) 0%, rgba(245, 158, 11, 0.1) 100%);
}

.toast-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    font-weight: var(--font-semibold);
    color: var(--color-text-primary);
}

.toast-body {
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* ==================== Light Theme ==================== */
[data-theme="light"] {
    --color-background: #f8fafc;
    --color-background-subtle: #f1f5f9;
    --color-surface: #ffffff;
    --color-surface-elevated: #ffffff;
    --color-surface-hover: #f1f5f9;
    --color-text-primary: #0f172a;
    --color-text-secondary: #475569;
    --color-text-muted: #94a3b8;
    --color-border: #e2e8f0;
    --color-border-subtle: #cbd5e1;
    --color-input-bg: #f8fafc;
    --color-input-border: #cbd5e1;

    --glass-bg: rgba(255, 255, 255, 0.9);
    --glass-border: rgba(0, 0, 0, 0.06);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.12);
}

[data-theme="light"] body::before {
    background-image:
        radial-gradient(circle at 25% 25%, rgba(20, 184, 166, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 75% 75%, rgba(99, 102, 241, 0.05) 0%, transparent 50%);
}

[data-theme="light"] body::after {
    opacity: 0.02;
}

[data-theme="light"] .card::before {
    background: linear-gradient(90deg, transparent, rgba(20, 184, 166, 0.15), transparent);
}

/* ==================== Theme Toggle ==================== */
.theme-toggle {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    width: 48px;
    height: 48px;
    border-radius: var(--radius-lg);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-secondary);
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-md);
    z-index: 1000;
    backdrop-filter: blur(10px);
    padding: 0;
}

.theme-toggle svg {
    display: block;
    margin: auto;
    transition: transform var(--transition-fast);
}

.theme-toggle:hover {
    background: var(--color-accent);
    border-color: var(--color-accent);
    color: var(--color-background);
    transform: scale(1.05) rotate(15deg);
    box-shadow: 0 8px 24px var(--color-accent-glow);
}

.theme-toggle:active {
    transform: scale(0.95);
}

/* ==================== Accessibility ==================== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

*:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

/* reduced motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0ms !important;
    }

    .app-name {
        animation: none;
    }
}

/* ==================== Success Card ==================== */
.success-card {
    text-align: center;
}

.success-card .card-title {
    color: var(--color-success);
}

/* ==================== Error Card ==================== */
.error-card {
    text-align: center;
}

.error-card .card-title {
    color: var(--color-error);
}