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

:root {
    --bg-primary: #0f1419;
    --bg-secondary: #1a1f2e;
    --bg-tertiary: #252b3b;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --accent: #58a6ff;
    --accent-hover: #79b8ff;
    --success: #3fb950;
    --error: #f85149;
    --warning: #d29922;
    --border: #30363d;
    --font-mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}

main {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.input-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
}

.input-section label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

#calldata-input {
    width: 100%;
    min-height: 120px;
    padding: 1rem;
    font-family: var(--font-mono);
    font-size: 0.875rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    resize: vertical;
    transition: border-color 0.2s;
}

#calldata-input:focus {
    outline: none;
    border-color: var(--accent);
}

#calldata-input::placeholder {
    color: var(--text-secondary);
}

.button-group {
    display: flex;
    gap: 0.75rem;
    margin-top: 1rem;
}

button {
    padding: 0.75rem 1.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

#decode-btn {
    background: var(--accent);
    color: var(--bg-primary);
}

#decode-btn:hover {
    background: var(--accent-hover);
}

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

button.secondary:hover {
    background: var(--border);
}

.output-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    min-height: 200px;
}

.placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 150px;
    color: var(--text-secondary);
}

.result-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.25rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.result-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
}

.selector-badge {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    background: var(--bg-tertiary);
    padding: 0.35rem 0.75rem;
    border-radius: 6px;
    color: var(--accent);
}

.result-card {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1rem;
    margin-bottom: 1rem;
}

.result-card:last-child {
    margin-bottom: 0;
}

.result-card h3 {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.signatures-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.signature-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.5rem 0.75rem;
    background: var(--bg-secondary);
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.2s;
}

.signature-item:hover {
    background: var(--border);
}

.signature-item.selected {
    border: 1px solid var(--accent);
    background: rgba(88, 166, 255, 0.1);
}

.signature-item input[type="radio"] {
    accent-color: var(--accent);
}

.signature-text {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    word-break: break-all;
}

.function-name {
    color: var(--warning);
}

.param-type {
    color: var(--accent);
}

.params-table {
    overflow-x: auto;
}

.param-row {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 0.5rem 1rem;
    padding: 0.75rem;
    background: var(--bg-secondary);
    border-radius: 6px;
    margin-bottom: 0.5rem;
    align-items: start;
}

.param-row:last-child {
    margin-bottom: 0;
}

.param-index {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-secondary);
    padding: 0.2rem 0.5rem;
    background: var(--bg-tertiary);
    border-radius: 4px;
}

.param-details {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    min-width: 0;
}

.param-type-label {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--accent);
}

.param-value {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    word-break: break-all;
    color: var(--text-primary);
}

.param-value.address {
    color: var(--success);
}

.param-value.number {
    color: var(--warning);
}

.param-value.bool {
    color: #c678dd;
}

.param-value.string {
    color: #98c379;
}

/* Tuple/Struct styling */
.tuple-container,
.array-container {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    margin-top: 0.5rem;
}

.collapsible-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    user-select: none;
    padding: 0.25rem 0;
    border-radius: 4px;
    transition: background 0.15s;
}

.collapsible-header:hover {
    background: rgba(255, 255, 255, 0.05);
}

.collapse-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
}

.chevron {
    display: inline-block;
    width: 0;
    height: 0;
    border-left: 5px solid transparent;
    border-right: 5px solid transparent;
    border-top: 6px solid var(--text-secondary);
    transition: transform 0.2s ease;
}

.expanded .chevron {
    transform: rotate(0deg);
}

.collapsed .chevron {
    transform: rotate(-90deg);
}

.collapse-preview {
    color: var(--text-secondary);
    font-size: 0.75rem;
    opacity: 0.7;
    margin-left: 0.25rem;
}

.expanded .collapse-preview {
    display: none;
}

.collapsed .collapse-preview {
    display: inline;
}

.tuple-header,
.tuple-footer,
.array-header,
.array-footer {
    color: var(--text-secondary);
}

.tuple-bracket,
.array-bracket {
    color: var(--text-secondary);
    font-weight: 600;
}

.collapsible-content {
    overflow: hidden;
    transition: max-height 0.2s ease, opacity 0.2s ease;
}

.expanded .collapsible-content {
    max-height: 10000px;
    opacity: 1;
}

.collapsed .collapsible-content {
    max-height: 0;
    opacity: 0;
}

.collapsible-footer {
    transition: opacity 0.2s ease;
}

.collapsed .collapsible-footer {
    display: none;
}

.tuple-fields,
.array-items {
    margin-left: 1.25rem;
    padding-left: 0.75rem;
    border-left: 2px solid var(--border);
}

.tuple-field,
.array-item {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 0.4rem 0;
    flex-wrap: wrap;
}

.tuple-field-index,
.array-item-index {
    color: var(--text-secondary);
    font-size: 0.75rem;
    min-width: 2rem;
    opacity: 0.7;
}

.tuple-field-type {
    color: var(--accent);
    font-size: 0.8rem;
    min-width: 80px;
}

/* Nested tuple/array styling */
.tuple-container .tuple-container,
.tuple-container .array-container,
.array-container .tuple-container,
.array-container .array-container {
    margin-top: 0.25rem;
}

.tuple-field > .param-value,
.array-item > .param-value {
    word-break: break-all;
}

.tuple-field > .param-value.address {
    color: var(--success);
}

.tuple-field > .param-value.number {
    color: var(--warning);
}

.tuple-field > .param-value.bool {
    color: #c678dd;
}

.tuple-field > .param-value.string {
    color: #98c379;
}

.raw-calldata {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    word-break: break-all;
    padding: 0.75rem;
    background: var(--bg-secondary);
    border-radius: 6px;
    color: var(--text-secondary);
    max-height: 150px;
    overflow-y: auto;
}

.error {
    background: rgba(248, 81, 73, 0.1);
    border: 1px solid var(--error);
    border-radius: 8px;
    padding: 1rem;
    color: var(--error);
}

.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    min-height: 150px;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.no-params {
    color: var(--text-secondary);
    font-style: italic;
}

footer {
    margin-top: 2rem;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

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

footer a:hover {
    text-decoration: underline;
}

@media (max-width: 600px) {
    .container {
        padding: 1rem;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .button-group {
        flex-direction: column;
    }

    button {
        width: 100%;
    }

    .result-header {
        flex-direction: column;
        align-items: flex-start;
    }
}