:root {
    --color-bg:              #ffffff;
    --color-bg-secondary:    #f5f5f7;
    --color-bg-tertiary:     #fafafa;
    --color-text-primary:    #1d1d1f;
    --color-text-secondary:  #6e6e73;
    --color-text-tertiary:   #86868b;
    --color-accent:          #0066cc;
    --color-accent-hover:    #0055b3;
    --color-accent-light:    #e8f0fe;
    --color-success:         #34c759;
    --color-success-bg:      #e8f8ed;
    --color-error:           #ff3b30;
    --color-error-bg:        #fef0ef;
    --color-border:          #d2d2d7;
    --color-border-light:    #e8e8ed;
    --color-separator:       #c6c6c8;

    --font-system:           -apple-system, BlinkMacSystemFont, 'SF Pro Text', 'SF Pro Display', system-ui, sans-serif;
    --font-mono:             'SF Mono', SFMono-Regular, ui-monospace, monospace;

    --text-xs:               12px;
    --text-sm:               14px;
    --text-base:             17px;
    --text-lg:               20px;
    --text-xl:               24px;
    --text-2xl:              32px;
    --text-3xl:              40px;

    --weight-light:          300;
    --weight-regular:        400;
    --weight-semibold:       600;
    --weight-bold:           700;

    --leading-tight:         1.15;
    --leading-normal:        1.47;
    --leading-relaxed:       1.6;

    --tracking-tight:        -0.022em;
    --tracking-normal:       -0.01em;
    --tracking-label:        0.06em;

    --space-xs:              4px;
    --space-sm:              8px;
    --space-md:              16px;
    --space-lg:              24px;
    --space-xl:              32px;
    --space-2xl:             48px;
    --space-3xl:             64px;

    --content-width:         720px;
    --content-width-wide:    960px;
    --radius-sm:             8px;
    --radius-md:             12px;
    --radius-lg:             18px;
    --radius-pill:           9999px;

    --shadow-sm:             0 1px 3px rgba(0,0,0,0.08);
    --shadow-md:             0 4px 12px rgba(0,0,0,0.08);
    --shadow-focus:          0 0 0 4px rgba(0,102,204,0.3);

    --ease-default:          cubic-bezier(0.25, 0.1, 0.25, 1);
    --duration-fast:         150ms;
    --duration-normal:       250ms;

    --touch-min:             44px;

    /* Motion */
    --ease-out-quart:        cubic-bezier(0.25, 1, 0.5, 1);
    --ease-out-expo:         cubic-bezier(0.16, 1, 0.3, 1);
    --duration-slow:         400ms;
    --duration-entrance:     900ms;
}

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

body {
    font-family: var(--font-system);
    font-size: var(--text-base);
    font-weight: var(--weight-regular);
    line-height: var(--leading-normal);
    letter-spacing: var(--tracking-normal);
    color: var(--color-text-primary);
    background: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100dvh;
}

h1, h2, h3 {
    font-weight: var(--weight-semibold);
    letter-spacing: var(--tracking-tight);
    line-height: var(--leading-tight);
}

h1 { font-size: var(--text-2xl); }
h2 { font-size: var(--text-xl); }
h3 { font-size: var(--text-lg); }

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

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

/* Layout */

.page-container {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: var(--space-lg) var(--space-md);
}

.page-container--wide {
    max-width: var(--content-width-wide);
}

/* Nav */

.nav {
    border-bottom: 1px solid var(--color-border-light);
    padding: var(--space-sm) var(--space-md);
    position: sticky;
    top: 0;
    background: var(--color-bg);
    z-index: 100;
}

.nav-inner {
    max-width: var(--content-width-wide);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: var(--touch-min);
}

.breadcrumb {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    flex: 1;
    min-width: 0;
}

.breadcrumb a {
    color: var(--color-text-secondary);
    white-space: nowrap;
}

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

.breadcrumb-separator {
    color: var(--color-text-tertiary);
}

.breadcrumb-current {
    color: var(--color-text-primary);
    font-weight: var(--weight-semibold);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.nav-back {
    display: none;
    align-items: center;
    gap: var(--space-xs);
    color: var(--color-accent);
    font-size: var(--text-base);
    min-height: var(--touch-min);
    padding: 0 var(--space-sm);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.nav-guide {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 1.5px solid var(--color-border);
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    min-height: var(--touch-min);
    min-width: var(--touch-min);
}

.nav-logout {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    padding: var(--space-xs) var(--space-sm);
    min-height: var(--touch-min);
    display: flex;
    align-items: center;
}

/* Buttons */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    border: none;
    border-radius: var(--radius-pill);
    padding: var(--space-sm) var(--space-lg);
    font-size: var(--text-base);
    font-family: var(--font-system);
    font-weight: var(--weight-semibold);
    min-height: var(--touch-min);
    cursor: pointer;
    transition: transform var(--duration-fast) var(--ease-default);
    text-decoration: none;
    line-height: 1;
}

.btn:active {
    transform: scale(0.97);
}

.btn-primary {
    background: var(--color-accent);
    color: #fff;
}

.btn-ghost {
    background: transparent;
    color: var(--color-accent);
    border: 1.5px solid var(--color-accent);
}

.btn-danger {
    background: transparent;
    color: var(--color-error);
    border: 1.5px solid var(--color-error);
}

.btn-sm {
    font-size: var(--text-sm);
    padding: var(--space-xs) var(--space-md);
    min-height: 36px;
}

.btn-block {
    width: 100%;
}

/* Form elements */

.field-label {
    display: block;
    font-size: var(--text-xs);
    font-weight: var(--weight-semibold);
    letter-spacing: var(--tracking-label);
    text-transform: uppercase;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xs);
}

.input-field {
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    font-size: var(--text-base);
    font-family: var(--font-system);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-bg);
    min-height: var(--touch-min);
    transition: border-color var(--duration-fast),
                box-shadow var(--duration-fast) var(--ease-default);
    color: var(--color-text-primary);
}

.input-field:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: var(--shadow-focus);
}

.input-field::placeholder {
    color: var(--color-text-tertiary);
}

textarea.input-field {
    resize: vertical;
    min-height: 88px;
    line-height: var(--leading-normal);
}

select.input-field {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M6 8L1 3h10z' fill='%236e6e73'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right var(--space-md) center;
    padding-right: var(--space-xl);
}

.form-group {
    margin-bottom: var(--space-lg);
}

.form-row {
    display: grid;
    gap: var(--space-md);
}

.form-error {
    font-size: var(--text-sm);
    color: var(--color-error);
    margin-top: var(--space-xs);
}

/* Cards */

.card {
    background: var(--color-bg);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    transition: box-shadow var(--duration-normal) var(--ease-default),
                transform var(--duration-normal) var(--ease-default);
    display: block;
    color: inherit;
}

a.card:hover {
    box-shadow: var(--shadow-md);
    color: inherit;
}

.card-title {
    font-size: var(--text-lg);
    font-weight: var(--weight-semibold);
    margin-bottom: var(--space-xs);
}

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

.card-grid {
    display: grid;
    gap: var(--space-md);
}

/* Status indicators */

.badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: var(--text-xs);
    font-weight: var(--weight-semibold);
    padding: 2px var(--space-sm);
    border-radius: var(--radius-pill);
}

.badge-success {
    background: var(--color-success-bg);
    color: #1a7f37;
}

.badge-error {
    background: var(--color-error-bg);
    color: var(--color-error);
}

/* Alert / Message */

.alert {
    padding: var(--space-md);
    border-radius: var(--radius-sm);
    font-size: var(--text-sm);
    margin-bottom: var(--space-lg);
}

.alert-error {
    background: var(--color-error-bg);
    color: var(--color-error);
}

.alert-success {
    background: var(--color-success-bg);
    color: #1a7f37;
}

/* Toast */

.toast {
    position: fixed;
    bottom: var(--space-xl);
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--color-text-primary);
    color: #fff;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-pill);
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    opacity: 0;
    transition: transform var(--duration-slow) var(--ease-out-expo),
                opacity var(--duration-normal) var(--ease-default);
    z-index: 1000;
    pointer-events: none;
}

.toast.visible {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

/* Empty state */

.empty-state {
    text-align: center;
    padding: var(--space-3xl) var(--space-lg);
    color: var(--color-text-secondary);
}

.empty-state h3 {
    margin-bottom: var(--space-sm);
    color: var(--color-text-primary);
}

.empty-state p {
    margin-bottom: var(--space-lg);
}

/* Login */

.login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100dvh;
    padding: var(--space-lg);
    background: var(--color-bg);
}

.login-card {
    width: 100%;
    max-width: 360px;
    text-align: center;
}

.login-icon {
    width: 72px;
    height: 72px;
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-md);
}

.login-title {
    font-size: var(--text-2xl);
    font-weight: var(--weight-semibold);
    letter-spacing: var(--tracking-tight);
    margin-bottom: var(--space-2xl);
}

.login-guide-link {
    display: inline-block;
    margin-top: var(--space-xl);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    text-decoration: none;
}

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

.login-card .form-group {
    text-align: left;
}

.login-card .btn {
    margin-top: var(--space-md);
}

/* Photo grid */

.photo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: var(--space-sm);
}

.photo-thumb {
    position: relative;
    aspect-ratio: 1;
    border-radius: var(--radius-sm);
    overflow: hidden;
    background: var(--color-bg-secondary);
}

.photo-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.photo-thumb-label {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 2px var(--space-sm);
    background: rgba(0,0,0,0.5);
    color: #fff;
    font-size: var(--text-xs);
    text-align: center;
}

.photo-confirmed::after {
    content: '\2713';
    position: absolute;
    bottom: var(--space-sm);
    right: var(--space-sm);
    width: 28px;
    height: 28px;
    background: var(--color-success);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--text-sm);
    font-weight: var(--weight-bold);
    box-shadow: var(--shadow-sm);
}

/* Upload states */

.photo-uploading::before {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(255,255,255,0.7);
    z-index: 1;
}

.photo-error {
    border: 2px solid var(--color-error);
}

/* Section collapsible */

.section-toggle {
    width: 100%;
    background: none;
    border: none;
    padding: var(--space-md) 0;
    font-family: var(--font-system);
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    color: var(--color-text-secondary);
    letter-spacing: var(--tracking-label);
    text-transform: uppercase;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    border-top: 1px solid var(--color-border-light);
}

.section-toggle::before {
    content: '\25B6';
    font-size: 10px;
    transition: transform var(--duration-fast);
}

details[open] > .section-toggle::before {
    transform: rotate(90deg);
}

/* Sticky bottom bar */

.bottom-bar {
    position: sticky;
    bottom: 0;
    background: var(--color-bg);
    border-top: 1px solid var(--color-border-light);
    padding: var(--space-md);
    z-index: 50;
    transition: box-shadow var(--duration-normal);
}

.bottom-bar.elevated {
    box-shadow: 0 -1px 3px rgba(0,0,0,0.05);
}

/* Page header */

.page-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-xl);
    gap: var(--space-md);
}

.page-header h1 {
    flex: 1;
    min-width: 0;
}

/* Confirm dialog */

.confirm-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.4);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 200;
    padding: var(--space-lg);
    opacity: 0;
    transition: opacity var(--duration-normal) var(--ease-default);
}

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

.confirm-dialog {
    background: var(--color-bg);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    max-width: 340px;
    width: 100%;
    text-align: center;
    transform: scale(0.95);
    opacity: 0;
    transition: transform var(--duration-normal) var(--ease-out-quart),
                opacity var(--duration-normal) var(--ease-default);
}

.confirm-overlay.visible .confirm-dialog {
    transform: scale(1);
    opacity: 1;
}

.confirm-dialog h3 {
    margin-bottom: var(--space-sm);
}

.confirm-dialog p {
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    margin-bottom: var(--space-lg);
}

.confirm-actions {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
}

/* Spinner */

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

.spinner {
    width: 24px;
    height: 24px;
    border: 3px solid var(--color-border-light);
    border-top-color: var(--color-accent);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

.uploading .spinner-overlay {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255,255,255,0.7);
    z-index: 1;
}

/* Animations */

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(12px); }
    to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}

@keyframes checkmarkPop {
    0%   { transform: scale(0); opacity: 0; }
    60%  { transform: scale(1.15); }
    100% { transform: scale(1); opacity: 1; }
}

@keyframes pulse {
    0%, 100% { opacity: 0.7; }
    50%      { opacity: 0.4; }
}

@keyframes counterFlash {
    0%   { color: var(--color-success); }
    100% { color: var(--color-text-secondary); }
}

/* Page entrance */
.page-container,
.page-container--wide,
.login-card,
.capture-page {
    animation: fadeInUp var(--duration-entrance) var(--ease-out-quart) both;
}

/* Staggered grid entrance */
.card-grid > *,
.comp-cards > *,
.photo-grid > * {
    animation: fadeIn var(--duration-slow) var(--ease-out-quart) both;
}

.card-grid > *:nth-child(1),
.comp-cards > *:nth-child(1),
.photo-grid > *:nth-child(1) { animation-delay: 0ms; }
.card-grid > *:nth-child(2),
.comp-cards > *:nth-child(2),
.photo-grid > *:nth-child(2) { animation-delay: 100ms; }
.card-grid > *:nth-child(3),
.comp-cards > *:nth-child(3),
.photo-grid > *:nth-child(3) { animation-delay: 200ms; }
.card-grid > *:nth-child(4),
.comp-cards > *:nth-child(4),
.photo-grid > *:nth-child(4) { animation-delay: 300ms; }
.card-grid > *:nth-child(5),
.comp-cards > *:nth-child(5),
.photo-grid > *:nth-child(5) { animation-delay: 400ms; }
.card-grid > *:nth-child(6),
.comp-cards > *:nth-child(6),
.photo-grid > *:nth-child(6) { animation-delay: 500ms; }
.card-grid > *:nth-child(n+7),
.comp-cards > *:nth-child(n+7),
.photo-grid > *:nth-child(n+7) { animation-delay: 500ms; }

/* Section toggle content */
details[open] > div {
    animation: fadeIn var(--duration-normal) var(--ease-default) both;
}

/* Empty state entrance */
.empty-state {
    animation: fadeInUp var(--duration-entrance) var(--ease-out-quart) both;
    animation-delay: 200ms;
}

/* Photo upload states */
.photo-uploading::before {
    animation: pulse 1.5s ease-in-out infinite;
}

.photo-confirmed::after {
    animation: checkmarkPop var(--duration-slow) var(--ease-out-quart) both;
}

/* Counter flash */
.counter-flash {
    animation: counterFlash 1.5s var(--ease-default);
}

/* Nav micro-interactions */
.breadcrumb a {
    transition: color var(--duration-fast);
}

.nav-guide {
    transition: border-color var(--duration-fast), color var(--duration-fast);
}

.nav-guide:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.nav-logout {
    transition: color var(--duration-fast);
}

.nav-logout:hover {
    color: var(--color-accent);
}

/* Photo thumb hover */
.photo-thumb img {
    transition: transform var(--duration-normal) var(--ease-out-quart);
}

.photo-thumb:hover img {
    transform: scale(1.05);
}

/* Badge entrance */
.badge {
    animation: fadeIn var(--duration-fast) var(--ease-default) both;
}

/* Responsive */

@media (min-width: 768px) {
    .form-row--2 {
        grid-template-columns: 1fr 1fr;
    }

    .form-group {
        margin-bottom: var(--space-xl);
    }

    .nav-back {
        display: none !important;
    }

    .breadcrumb {
        display: flex !important;
    }

    .photo-grid {
        grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    }

    a.card:hover {
        transform: translateY(-2px);
    }

    .card-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (min-width: 768px) and (max-width: 960px) {
    .page-header {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 767px) {
    .breadcrumb {
        display: none;
    }

    .nav-back {
        display: flex;
    }

    h1 {
        font-size: var(--text-xl);
    }

    .page-container {
        padding: var(--space-md) var(--space-md);
    }
}

/* Reduced motion */

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Utility */

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

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

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

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }