/* Proof State Stepper */
.proof-stepper {
    border: 1px solid var(--border);
    border-radius: 10px;
    background: var(--bg-raised);
    overflow: hidden;
    margin: 2rem 0;
}

/* Header bar */
.stepper-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    background: var(--code-bg);
    border-bottom: 1px solid var(--border);
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--text-muted);
}

.stepper-title {
    color: var(--accent);
}

.stepper-counter {
    color: var(--text-muted);
}

/* Main panels */
.stepper-body {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0;
    min-height: 180px;
}

.stepper-panel {
    padding: 1.25rem;
    position: relative;
}

.stepper-panel-label {
    font-family: var(--mono);
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

/* Hypotheses panel */
.stepper-hypotheses {
    border-right: 1px solid var(--border);
}

.hyp-item {
    font-family: var(--mono);
    font-size: 0.85rem;
    padding: 0.3rem 0.5rem;
    border-radius: 4px;
    margin-bottom: 0.25rem;
    transition: all 0.4s ease;
    opacity: 1;
}

.hyp-name {
    color: var(--accent);
}

.hyp-type {
    color: var(--text);
}

.hyp-colon {
    color: var(--text-muted);
}

.hyp-item.hyp-new {
    background: rgba(126, 184, 218, 0.12);
    border-left: 2px solid var(--accent);
    animation: hyp-enter 0.4s ease;
}

.hyp-item.hyp-removed {
    opacity: 0.3;
    text-decoration: line-through;
    color: #e55;
    animation: hyp-exit 0.4s ease;
}

.hyp-item.hyp-entering {
    animation: hyp-enter 0.4s ease;
}

@keyframes hyp-enter {
    from {
        opacity: 0;
        transform: translateX(-10px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes hyp-exit {
    from { opacity: 1; }
    to { opacity: 0.3; }
}

/* Goal panel */
.stepper-goals {
    display: flex;
    flex-direction: column;
}

.goal-item {
    font-family: var(--mono);
    font-size: 1.1rem;
    color: var(--text);
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    border: 1px solid var(--border);
    background: var(--code-bg);
    margin-bottom: 0.5rem;
    transition: all 0.4s ease;
    text-align: center;
}

.goal-item.goal-changed {
    border-color: var(--accent);
    animation: goal-pulse 0.5s ease;
}

@keyframes goal-pulse {
    0% { border-color: var(--border); }
    50% { border-color: var(--accent); box-shadow: 0 0 12px rgba(126, 184, 218, 0.2); }
    100% { border-color: var(--accent); }
}

.goal-qed {
    color: #5cb85c;
    font-size: 1rem;
    text-align: center;
    padding: 1.5rem;
    font-weight: 500;
}

.goal-qed-symbol {
    font-size: 2rem;
    display: block;
    margin-bottom: 0.25rem;
}

/* Tactic bar */
.stepper-tactic {
    padding: 1rem 1.25rem;
    border-top: 1px solid var(--border);
    min-height: 3.5rem;
}

.tactic-code {
    font-family: var(--mono);
    font-size: 0.9rem;
    color: #c9a0dc;
    margin-bottom: 0.25rem;
}

.tactic-code::before {
    content: "▸ ";
    color: var(--accent);
}

.tactic-explanation {
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.5;
}

.tactic-initial {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-style: italic;
}

/* Timeline */
.stepper-timeline {
    display: flex;
    align-items: center;
    padding: 0.75rem 1.25rem;
    border-top: 1px solid var(--border);
    background: var(--code-bg);
    gap: 0.75rem;
}

.stepper-btn {
    background: none;
    border: 1px solid var(--border);
    color: var(--text-muted);
    width: 32px;
    height: 32px;
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    transition: all 0.2s;
    flex-shrink: 0;
}

.stepper-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.stepper-btn:disabled {
    opacity: 0.3;
    cursor: default;
}

.stepper-btn:disabled:hover {
    border-color: var(--border);
    color: var(--text-muted);
}

.stepper-track {
    flex: 1;
    display: flex;
    align-items: center;
    gap: 0;
    position: relative;
    height: 32px;
}

.stepper-dot {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    border: 2px solid var(--border);
    background: var(--bg);
    cursor: pointer;
    transition: all 0.2s;
    position: relative;
    z-index: 2;
    flex-shrink: 0;
}

.stepper-dot:hover {
    border-color: var(--accent);
    transform: scale(1.2);
}

.stepper-dot.dot-active {
    background: var(--accent);
    border-color: var(--accent);
    box-shadow: 0 0 8px rgba(126, 184, 218, 0.4);
}

.stepper-dot.dot-visited {
    background: var(--accent-dim);
    border-color: var(--accent-dim);
}

.stepper-dot.dot-qed {
    background: #5cb85c;
    border-color: #5cb85c;
}

.stepper-line {
    flex: 1;
    height: 2px;
    background: var(--border);
    min-width: 8px;
}

.stepper-line.line-visited {
    background: var(--accent-dim);
}

.stepper-keys {
    font-family: var(--mono);
    font-size: 0.65rem;
    color: var(--text-muted);
    opacity: 0.5;
    flex-shrink: 0;
}

/* Responsive */
@media (max-width: 640px) {
    .stepper-body {
        grid-template-columns: 1fr;
    }
    .stepper-hypotheses {
        border-right: none;
        border-bottom: 1px solid var(--border);
    }
    .stepper-keys { display: none; }
}