/* --- Color Variables (Light Mode Default) --- */
:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: rgba(37, 99, 235, 0.1);

    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-color: #1f2937;
    --muted-text: #6b7280;
    --border-color: #e5e7eb;
    --border-hover: #d1d5db;

    --input-bg: #ffffff;
    --input-border: #d1d5db;

    --error-color: #dc2626;
    --error-bg: #fef2f2;
    --error-border: #fecaca;
    --success-color: #16a34a;
    --success-bg: #f0fdf4;
    --success-border: #bbf7d0;
    --warning-color: #d97706;
    --warning-bg: #fffbeb;

    --info-bg: #eff6ff;
    --info-border: #3b82f6;
    --info-text: #1e40af;

    --detail-bg: #f8fafc;
    --detail-text: #475569;
    --detail-strong: #334155;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);

    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;

    --transition-fast: 150ms ease;
    --transition-normal: 200ms ease;
    --transition-slow: 300ms ease;
}

/* --- Dark Mode Overrides --- */
@media (prefers-color-scheme: dark) {
    :root {
        --primary-color: #3b82f6;
        --primary-hover: #60a5fa;
        --primary-light: rgba(59, 130, 246, 0.15);

        --bg-color: #0f172a;
        --card-bg: #1e293b;
        --text-color: #f1f5f9;
        --muted-text: #94a3b8;
        --border-color: #334155;
        --border-hover: #475569;

        --input-bg: #0f172a;
        --input-border: #475569;

        --error-color: #f87171;
        --error-bg: rgba(239, 68, 68, 0.1);
        --error-border: rgba(239, 68, 68, 0.3);
        --success-color: #4ade80;
        --success-bg: rgba(74, 222, 128, 0.1);
        --success-border: rgba(74, 222, 128, 0.3);
        --warning-color: #fbbf24;
        --warning-bg: rgba(251, 191, 36, 0.1);

        --info-bg: rgba(59, 130, 246, 0.15);
        --info-border: #3b82f6;
        --info-text: #93c5fd;

        --detail-bg: #0f172a;
        --detail-text: #cbd5e1;
        --detail-strong: #f1f5f9;

        --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
        --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
        --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 2rem 1rem;
    transition: background-color var(--transition-slow), color var(--transition-slow);
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: 1rem;
    right: 1rem;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.toast {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 0.875rem 1rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    min-width: 280px;
    max-width: 400px;
    animation: slideIn 0.3s ease, fadeOut 0.3s ease 2.7s forwards;
    font-size: 0.875rem;
}

.toast.success { border-left: 4px solid var(--success-color); }
.toast.error { border-left: 4px solid var(--error-color); }
.toast.info { border-left: 4px solid var(--primary-color); }

.toast-icon { font-size: 1.25rem; flex-shrink: 0; }

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

@keyframes fadeOut {
    from { opacity: 1; }
    to { opacity: 0; transform: translateX(50%); }
}

/* Container */
.container {
    background-color: var(--card-bg);
    width: 100%;
    max-width: 640px;
    padding: 2.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    transition: background-color var(--transition-slow), border-color var(--transition-slow);
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 2rem;
}

.header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--primary-color), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header p {
    color: var(--muted-text);
    font-size: 0.95rem;
}

/* Progress Indicator */
.progress-bar {
    display: flex;
    justify-content: space-between;
    margin-bottom: 2rem;
    position: relative;
}

.progress-bar::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--border-color);
    transform: translateY(-50%);
    z-index: 0;
}

.progress-bar::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    height: 2px;
    background: var(--primary-color);
    transform: translateY(-50%);
    z-index: 1;
    transition: width var(--transition-slow);
    width: var(--progress, 0%);
}

.progress-step {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--muted-text);
    z-index: 2;
    transition: all var(--transition-normal);
}

.progress-step.active {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.progress-step.completed {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

/* Info Box */
.info-box {
    background-color: var(--info-bg);
    border-left: 4px solid var(--info-border);
    color: var(--info-text);
    padding: 1rem 1.25rem;
    /*margin-bottom: 2rem; */
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    display: flex;
    gap: 0.75rem;
    align-items: flex-start;
}

.info-box-icon {
    font-size: 1.25rem;
    flex-shrink: 0;
}

.info-box p { margin-bottom: 0.25rem; }
.info-box p:last-child { margin-bottom: 0; }

/* Form Sections */
.form-section {
    margin-bottom: 1.5rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.form-section:last-of-type {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.section-title {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--muted-text);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.section-title::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border-color);
}

/* Form Groups */
.form-group {
    margin-bottom: 1.25rem;
    position: relative;
}

.form-group:last-child { margin-bottom: 0; }

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

@media (max-width: 500px) {
    .form-row { grid-template-columns: 1fr; }
}

label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    font-weight: 500;
    font-size: 0.9rem;
}

.required-star {
    color: var(--error-color);
    font-weight: 400;
}

.optional-tag {
    color: var(--muted-text);
    font-weight: 400;
    font-size: 0.8rem;
    margin-left: auto;
}

.help-text {
    font-size: 0.8rem;
    color: var(--muted-text);
    margin-top: 0.35rem;
}

/* Tooltip */
.tooltip-trigger {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--border-color);
    color: var(--muted-text);
    font-size: 0.65rem;
    font-weight: 700;
    cursor: help;
    position: relative;
}

.tooltip-trigger:hover::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%);
    background: var(--text-color);
    color: var(--bg-color);
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 400;
    white-space: nowrap;
    max-width: 250px;
    z-index: 100;
    box-shadow: var(--shadow-md);
}

/* Inputs */
input[type="text"],
input[type="number"],
select,
textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    background-color: var(--input-bg);
    color: var(--text-color);
    border: 1px solid var(--input-border);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-family: inherit;
    transition: all var(--transition-fast);
}

/* Remove number input spinners */
input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}
input[type="number"] {
    -moz-appearance: textfield;
}

input::placeholder,
textarea::placeholder {
    color: var(--muted-text);
    opacity: 0.7;
}

input:-webkit-autofill,
input:-webkit-autofill:hover,
input:-webkit-autofill:focus {
    -webkit-box-shadow: 0 0 0 30px var(--input-bg) inset !important;
    -webkit-text-fill-color: var(--text-color) !important;
}

input:hover:not(:focus):not(.error),
select:hover:not(:focus):not(.error),
textarea:hover:not(:focus):not(.error) {
    border-color: var(--border-hover);
}

input:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-light);
}

select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    padding-right: 2.5rem;
}

textarea {
    resize: vertical;
    min-height: 100px;
    line-height: 1.5;
}

/* Input with button */
.input-with-button {
    display: flex;
    gap: 0.5rem;
}

.input-with-button input {
    flex: 1;
}

.input-with-button button {
    flex-shrink: 0;
    padding: 0.75rem 1rem;
    margin-top: 0;
    width: auto;
    font-size: 0.875rem;
}

/* Validation States */
input.error,
select.error,
textarea.error {
    border-color: var(--error-color);
    background-color: var(--error-bg);
}

input.error:focus,
select.error:focus {
    box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1);
}

input.success,
select.success,
textarea.success {
    border-color: var(--success-color);
}

input.success:focus,
select.success:focus {
    box-shadow: 0 0 0 3px rgba(22, 163, 74, 0.1);
}

.error-msg {
    color: var(--error-color);
    font-size: 0.8rem;
    margin-top: 0.35rem;
    display: flex;
    align-items: center;
    gap: 0.35rem;
    animation: shake 0.3s ease;
}

.error-msg.hidden { display: none; }

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-4px); }
    75% { transform: translateX(4px); }
}

/* Details Box */
.details-box {
    background-color: var(--detail-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    margin-top: 0.75rem;
    font-size: 0.85rem;
    color: var(--detail-text);
    animation: expandIn 0.2s ease;
}

.details-box.hidden { display: none; }

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

.details-row {
    display: flex;
    align-items: flex-start;
    padding: 0.4rem 0;
    border-bottom: 1px dashed var(--border-color);
}

.details-row:last-child { border-bottom: none; }

.details-label {
    font-weight: 600;
    color: var(--detail-strong);
    min-width: 100px;
    flex-shrink: 0;
}

.details-value {
    flex: 1;
    word-break: break-all;
    font-family: 'SF Mono', 'Consolas', monospace;
    font-size: 0.8rem;
}

.copy-btn {
    background: transparent;
    border: none;
    color: var(--muted-text);
    cursor: pointer;
    padding: 0.25rem;
    margin-left: 0.5rem;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    width: auto;
    margin-top: 0;
}

.copy-btn:hover {
    color: var(--primary-color);
    background: var(--primary-light);
}

.details-note {
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border-color);
    font-style: italic;
    color: var(--muted-text);
}

/* Ping Status */
.ping-status {
    font-size: 0.85rem;
    margin-top: 0.75rem;
    padding: 0.75rem;
    border-radius: var(--radius-md);
    background: var(--detail-bg);
    border: 1px solid var(--border-color);
}

.ping-status.hidden { display: none; }

.ping-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--detail-strong);
}

.ping-results {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.ping-result-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.35rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
}

.ping-result-row.best {
    background: var(--success-bg);
    border: 1px solid var(--success-border);
}

.ping-result-row.selected {
    background: var(--primary-light);
    border: 1px solid var(--primary-color);
}

.ping-result-row.selected.best {
    background: var(--success-bg);
    border: 1px solid var(--success-color);
}

.ping-node-name {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.ping-latency {
    font-family: 'SF Mono', 'Consolas', monospace;
    font-weight: 600;
}

.ping-latency.good { color: var(--success-color); }
.ping-latency.medium { color: var(--warning-color); }
.ping-latency.poor { color: var(--error-color); }

.ping-suggestion {
    margin-top: 0.75rem;
    padding: 0.6rem 0.75rem;
    background: var(--warning-bg);
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    color: var(--warning-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.ping-suggestion.hidden { display: none; }

.ping-suggestion button {
    margin: 0;
    margin-left: auto;
    padding: 0.35rem 0.75rem;
    font-size: 0.75rem;
    width: auto;
    background: var(--warning-color);
}

.ping-suggestion button:hover {
    background: #b45309;
}


.loader {
    border: 1px solid #f3f3f3; /* Light grey */
    border-top: 1px solid #3498db; /* Blue */
    border-radius: 50%;
    width: 0.8rem;
    height: 0.8rem;
    animation: spin 0.5s linear infinite;
    margin: 0.2rem 0;
    margin-right: 0.2rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Buttons */
button {
    width: 100%;
    padding: 0.875rem 1.5rem;
    background: linear-gradient(135deg, var(--primary-color), #4f46e5);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    margin-top: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    position: relative;
    overflow: hidden;
}

button::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, transparent, rgba(255,255,255,0.1));
    opacity: 0;
    transition: opacity var(--transition-fast);
}

button:hover:not(:disabled)::before { opacity: 1; }

button:hover:not(:disabled) {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.4);
}

button:active:not(:disabled) {
    transform: translateY(0);
}

button:disabled {
    background: var(--muted-text);
    cursor: not-allowed;
    opacity: 0.6;
}

button.secondary {
    background: transparent;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

button.secondary:hover:not(:disabled) {
    background: var(--primary-light);
    box-shadow: none;
}

/* Global Error */
.global-error {
    text-align: center;
    color: var(--error-color);
    background: var(--error-bg);
    border: 1px solid var(--error-border);
    padding: 0.75rem;
    border-radius: var(--radius-sm);
    font-weight: 500;
    margin-top: 1rem;
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.global-error.hidden { display: none; }

/* Success Screen */
.success-screen {
    text-align: center;
    padding: 2rem 0;
}

.success-screen.hidden { display: none; }

.success-icon {
    width: 80px;
    height: 80px;
    background: var(--success-bg);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 2.5rem;
    color: var(--success-color);
    animation: scaleIn 0.3s ease;
}

@keyframes scaleIn {
    from { transform: scale(0); }
    to { transform: scale(1); }
}

.success-screen h2 {
    color: var(--success-color);
    margin-bottom: 0.5rem;
}

.success-screen p {
    color: var(--muted-text);
    margin-bottom: 1rem;
}

/* Responsive */
@media (max-width: 640px) {
    body { padding: 1rem 0.5rem; }
    .container { padding: 1.5rem; }
    .header h1 { font-size: 1.5rem; }
    .tooltip-trigger:hover::after {
        left: 0;
        transform: none;
        white-space: normal;
    }
    .ping-result-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.25rem;
    }
}