:root {
    --color-primary: #2d5a27;
    --color-primary-dark: #1e3d1a;
    --color-primary-light: #4a8c42;
    --color-danger: #dc3545;
    --color-danger-dark: #a71d2a;
    --color-secondary: #6c757d;
    --color-secondary-dark: #545b62;
    --color-success: #28a745;
    --color-warning: #ffc107;
    --color-background: #f5f5f5;
    --color-surface: #ffffff;
    --color-text: #212529;
    --color-text-muted: #6c757d;
    --color-border: #dee2e6;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
}

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

/* ── Skip link for keyboard navigation ──────────── */
.skip-link {
    position: absolute;
    top: -100%;
    left: var(--spacing-md);
    z-index: 9999;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-primary);
    color: white;
    border-radius: var(--radius-sm);
    font-weight: 600;
    text-decoration: none;
}

.skip-link:focus {
    top: var(--spacing-sm);
}

html, body {
    height: 100%;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    font-size: 16px;
    line-height: 1.5;
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-tap-highlight-color: transparent;
    -webkit-font-smoothing: antialiased;
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100%;
    max-width: 600px;
    margin: 0 auto;
    background-color: var(--color-surface);
}

.app-header {
    background: var(--color-primary);
    color: white;
    padding: var(--spacing-md);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.app-header h1 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0;
}

.unit-toggle {
    display: flex;
    gap: 1px;
    background: rgba(255,255,255,0.2);
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.unit-btn {
    padding: 4px 10px;
    font-size: 0.75rem;
    font-weight: 600;
    border: none;
    background: rgba(255,255,255,0.15);
    color: rgba(255,255,255,0.9);
    cursor: pointer;
    transition: all 0.15s;
}

.unit-btn:focus-visible {
    outline: 2px solid white;
    outline-offset: 1px;
}

.unit-btn.active {
    background: rgba(255,255,255,0.95);
    color: var(--color-primary);
}

.app-main {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-md);
    padding-bottom: 80px;
}

.view {
    display: none;
}

.view.active {
    display: block;
}

.stats-panel {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.stats-panel.compact {
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-sm);
}

.stat {
    background: var(--color-background);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    text-align: center;
}

.stats-panel.compact .stat {
    padding: var(--spacing-sm);
}

.stat-label {
    display: block;
    font-size: 0.75rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: var(--spacing-xs);
}

.stats-panel.compact .stat-label {
    font-size: 0.65rem;
    margin-bottom: 0;
}

.stat-value {
    display: block;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
}

.stats-panel.compact .stat-value {
    font-size: 1rem;
}

.controls {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.controls.compact {
    margin-bottom: var(--spacing-sm);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
    touch-action: manipulation;
}

.btn:focus-visible {
    outline: 3px solid var(--color-primary-light);
    outline-offset: 2px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-primary {
    background: var(--color-primary);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: var(--color-primary-dark);
}

.btn-primary:active:not(:disabled) {
    transform: scale(0.98);
}

.btn-secondary {
    background: var(--color-secondary);
    color: white;
}

.btn-secondary:hover:not(:disabled) {
    background: var(--color-secondary-dark);
}

.btn-danger {
    background: var(--color-danger);
    color: white;
}

.btn-danger:hover:not(:disabled) {
    background: var(--color-danger-dark);
}

.btn-large {
    padding: var(--spacing-lg) var(--spacing-xl);
    font-size: 1.125rem;
    min-height: 64px;
}

.btn-icon {
    font-size: 1.25em;
}

.hidden {
    display: none !important;
}

.recording-indicator {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: rgba(220, 53, 69, 0.1);
    border-radius: var(--radius-md);
    color: var(--color-danger);
    font-weight: 600;
    font-size: 0.875rem;
    margin-bottom: var(--spacing-sm);
}

.pulse {
    width: 12px;
    height: 12px;
    background: var(--color-danger);
    border-radius: 50%;
    animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.2); }
}

.measurement-summary {
    background: var(--color-background);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
}

.summary-item {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--color-border);
}

.summary-item:last-child {
    border-bottom: none;
}

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

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.form-group input {
    width: 100%;
    padding: var(--spacing-md);
    font-size: 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: border-color 0.2s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--color-primary);
}

.form-actions {
    display: flex;
    gap: var(--spacing-md);
}

.form-actions .btn {
    flex: 1;
}

.measurements-list {
    margin-bottom: var(--spacing-lg);
}

.empty-state {
    text-align: center;
    color: var(--color-text-muted);
    padding: var(--spacing-xl);
}

.measurement-card {
    background: var(--color-background);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.measurement-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.measurement-card-title {
    font-weight: 600;
    font-size: 1.125rem;
}

.measurement-card-date {
    font-size: 0.75rem;
    color: var(--color-text-muted);
}

.measurement-card-stats {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.measurement-card-stat {
    font-size: 0.875rem;
}

.measurement-card-stat strong {
    color: var(--color-primary);
}

.measurement-card-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: flex-end;
}

.measurement-card-actions .btn {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
}

.history-actions {
    display: flex;
    justify-content: center;
}

.app-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    display: flex;
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    max-width: 600px;
    margin: 0 auto;
}

.nav-btn {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    background: none;
    border: none;
    color: var(--color-text-muted);
    cursor: pointer;
    transition: color 0.2s;
}

.nav-btn:focus-visible {
    outline: 3px solid var(--color-primary-light);
    outline-offset: -2px;
}

.nav-btn.active {
    color: var(--color-primary);
}

.nav-icon {
    font-size: 1.5rem;
    margin-bottom: 2px;
}

.nav-label {
    font-size: 0.75rem;
    font-weight: 500;
}

.modal {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
    z-index: 1000;
}

.modal-content {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    width: 100%;
    max-width: 400px;
    box-shadow: var(--shadow-lg);
}

.modal-content h3 {
    margin-bottom: var(--spacing-md);
}

.modal-content p {
    margin-bottom: var(--spacing-lg);
    color: var(--color-text-muted);
}

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

.toast {
    position: fixed;
    bottom: 80px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-text);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}

h2 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-lg);
}

.loop-indicator {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: rgba(40, 167, 69, 0.15);
    border: 2px solid var(--color-success);
    border-radius: var(--radius-md);
    color: var(--color-success);
    font-weight: 600;
    font-size: 0.875rem;
    margin-bottom: var(--spacing-sm);
    animation: loopPulse 2s ease-in-out infinite;
}

.loop-icon {
    font-size: 1rem;
}

@keyframes loopPulse {
    0%, 100% { background: rgba(40, 167, 69, 0.15); }
    50% { background: rgba(40, 167, 69, 0.25); }
}

.map-container {
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    flex: 1;
    min-height: 0;
}

#recording-map {
    height: 100%;
    width: 100%;
    min-height: 180px;
    background: var(--color-background);
}

.history-map {
    height: 150px;
    width: 100%;
    border-radius: var(--radius-sm);
    margin-top: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    background: var(--color-background);
}

.recording-layout {
    display: flex;
    flex-direction: column;
    height: calc(100vh - 140px);
    padding-bottom: 60px;
}

/* Calculator */

.calc-area-source {
    margin-bottom: var(--spacing-md);
}

.calc-toggle-row {
    display: flex;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-sm);
}

.btn-sm {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.8125rem;
}

.calc-src-btn,
.calc-fert-type-btn,
.calc-seed-type-btn {
    flex: 1;
    background: var(--color-background);
    color: var(--color-text-muted);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s;
}

.calc-src-btn.active,
.calc-fert-type-btn.active,
.calc-seed-type-btn.active {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

.calc-field {
    margin-bottom: var(--spacing-md);
}

.calc-field select {
    width: 100%;
    padding: var(--spacing-md);
    font-size: 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-surface);
    color: var(--color-text);
    appearance: auto;
}

.calc-field select:focus {
    outline: none;
    border-color: var(--color-primary);
}

.calc-input-group {
    display: flex;
    align-items: center;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: border-color 0.2s;
}

.calc-input-group:focus-within {
    border-color: var(--color-primary);
}

.calc-input-group input {
    flex: 1;
    padding: var(--spacing-md);
    font-size: 1rem;
    border: none;
    outline: none;
    min-width: 0;
}

.calc-unit {
    padding: var(--spacing-md);
    background: var(--color-background);
    color: var(--color-text-muted);
    font-size: 0.875rem;
    font-weight: 600;
    white-space: nowrap;
}

.calc-hint {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    margin-top: var(--spacing-xs);
}

.calc-area-display {
    background: var(--color-background);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    color: var(--color-primary);
    font-weight: 600;
    text-align: center;
    margin-top: var(--spacing-sm);
}

.form-label {
    display: block;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    font-size: 0.875rem;
}

.calc-tabs {
    display: flex;
    gap: 2px;
    background: var(--color-border);
    border-radius: var(--radius-md);
    padding: 2px;
    margin-bottom: var(--spacing-md);
}

.calc-tab {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
    font-weight: 600;
    background: var(--color-surface);
    border: none;
    cursor: pointer;
    color: var(--color-text-muted);
    transition: all 0.15s;
}

.calc-tab:first-child {
    border-radius: var(--radius-sm) 0 0 var(--radius-sm);
}

.calc-tab:last-child {
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.calc-tab.active {
    background: var(--color-primary);
    color: white;
}

.calc-panel {
    display: none;
}

.calc-panel.active {
    display: block;
}

.calc-btn {
    width: 100%;
    margin-bottom: var(--spacing-md);
}

.calc-result {
    background: var(--color-background);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    border-left: 4px solid var(--color-primary);
}

.calc-result-title {
    font-weight: 700;
    font-size: 1rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.calc-result-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.calc-result-detail {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-xs);
}

/* ── Ads ──────────────────────────────────────────── */

.ad-banner {
    position: fixed;
    bottom: 56px;
    left: 0;
    right: 0;
    max-width: 600px;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    background: var(--color-background);
    border-top: 1px solid var(--color-border);
    z-index: 99;
    padding: var(--spacing-xs) 0;
}

.ad-banner.hidden {
    display: none !important;
}

/* Push content up when banner is visible */
.app-main.has-ad-banner {
    padding-bottom: 130px;
}

.ad-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    background: var(--color-background);
    color: var(--color-text-muted);
    font-size: 0.8125rem;
}

.ad-placeholder-banner {
    width: 320px;
    height: 50px;
    border: 1px dashed var(--color-border);
    border-radius: var(--radius-sm);
}

.ad-placeholder-label {
    background: var(--color-border);
    color: var(--color-text-muted);
    font-size: 0.625rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 1px 6px;
    border-radius: 3px;
}

.ad-placeholder-interstitial {
    width: 300px;
    height: 250px;
    border: 1px dashed var(--color-border);
    border-radius: var(--radius-md);
    flex-direction: column;
    gap: var(--spacing-sm);
}

.ad-placeholder-text {
    font-weight: 600;
    color: var(--color-text-muted);
}

.ad-placeholder-sub {
    font-size: 0.75rem;
}

/* Interstitial full-screen overlay */
.ad-interstitial {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    animation: adFadeIn 0.25s ease;
}

.ad-interstitial.hidden {
    display: none !important;
}

@keyframes adFadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.ad-interstitial-container {
    position: relative;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl) var(--spacing-lg) var(--spacing-lg);
    max-width: 340px;
    width: 90%;
    box-shadow: var(--shadow-lg);
    animation: adSlideUp 0.3s ease;
}

@keyframes adSlideUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

.ad-interstitial-close {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: none;
    background: var(--color-background);
    color: var(--color-text-muted);
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.15s;
    z-index: 1;
}

.ad-interstitial-close:hover {
    background: var(--color-border);
    color: var(--color-text);
}

.ad-interstitial-close.hidden {
    display: none !important;
}

.ad-interstitial-body {
    display: flex;
    justify-content: center;
}

/* ── Ad Disclosure Labels ────────────────────────── */
.ad-disclosure {
    position: absolute;
    top: var(--spacing-xs);
    left: var(--spacing-sm);
    font-size: 0.625rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--color-text-muted);
    background: var(--color-border);
    padding: 1px 5px;
    border-radius: 3px;
    z-index: 1;
    line-height: 1.4;
}

.ad-banner {
    position: relative;
}

.ad-disclosure-interstitial {
    top: var(--spacing-sm);
    left: var(--spacing-md);
}

/* ── Footer ──────────────────────────────────────── */
.app-footer {
    text-align: center;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.75rem;
    color: var(--color-text-muted);
    border-top: 1px solid var(--color-border);
    background: var(--color-surface);
}

.app-footer a {
    color: var(--color-text-muted);
    text-decoration: none;
}

.app-footer a:hover {
    color: var(--color-primary);
    text-decoration: underline;
}

.app-footer a:focus-visible {
    outline: 2px solid var(--color-primary-light);
    outline-offset: 2px;
}

.footer-sep {
    margin: 0 var(--spacing-sm);
}

/* ── Responsive ──────────────────────────────────── */
@media (min-width: 480px) {
    .stats-panel:not(.compact) {
        gap: var(--spacing-md);
    }

    .stats-panel:not(.compact) .stat-value {
        font-size: 1.5rem;
    }
}

/* ── Reduced Motion ──────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
    .pulse,
    .loop-indicator,
    .toast,
    .ad-interstitial,
    .ad-interstitial-container,
    .gps-warming-up {
        animation: none !important;
        transition: none !important;
    }
}

/* ── Print ───────────────────────────────────────── */
@media print {
    .app-nav,
    .app-header,
    .ad-banner,
    .ad-interstitial,
    .app-footer,
    .controls,
    .recording-indicator,
    .loop-indicator {
        display: none !important;
    }
    .app-main {
        padding: 0;
    }
}