body {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
}

.reg-card {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 540px;
    padding: 40px;
    animation: cardAppear 1s cubic-bezier(0.16, 1, 0.3, 1);
}

/* === STEPPER === */
.stepper {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    margin-bottom: 36px;
}
.step-dot {
    width: 34px; height: 34px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(42, 42, 53, 0.6);
    border: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 13px;
    font-weight: 700;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    flex-shrink: 0;
}
.step-dot.active {
    background: linear-gradient(135deg, var(--accent), var(--accent-hover));
    border-color: rgba(74, 118, 240, 0.6);
    color: #fff;
    box-shadow: 0 0 20px rgba(74, 118, 240, 0.5);
}
.step-dot.done {
    background: rgba(74, 118, 240, 0.15);
    border-color: rgba(74, 118, 240, 0.4);
    color: var(--accent);
    font-size: 15px;
}
.step-line {
    width: 28px; height: 1px;
    background: rgba(255, 255, 255, 0.06);
    transition: background 0.4s;
    flex-shrink: 0;
}
.step-line.active { background: rgba(74, 118, 240, 0.5); }

/* === STEP CONTENT === */
.step-content { display: none; animation: stepIn 0.5s cubic-bezier(0.16, 1, 0.3, 1); }
.step-content.active { display: block; }

.reg-card h1 {
    font-size: 26px;
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: 10px;
    background: linear-gradient(135deg, #fff, #8b8b9a);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.2;
}
.step-sub {
    color: var(--text-dim);
    font-size: 14px;
    line-height: 1.6;
    margin-bottom: 24px;
}

/* === OS GRID === */
.os-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-bottom: 18px;
}
.os-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: linear-gradient(135deg, rgba(42, 42, 53, 0.5), rgba(30, 30, 40, 0.5));
    border: 1px solid var(--border);
    border-radius: 14px;
    color: #fff;
    font-size: 14px;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    text-align: left;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    overflow: hidden;
}
.os-btn::after {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at center, rgba(74, 118, 240, 0.15), transparent 70%);
    opacity: 0;
    transition: opacity 0.3s;
}
.os-btn:hover {
    border-color: rgba(74, 118, 240, 0.4);
    transform: translateY(-2px);
    box-shadow: 0 10px 28px rgba(74, 118, 240, 0.15);
}
.os-btn:hover::after { opacity: 1; }
.os-btn.selected {
    background: linear-gradient(135deg, rgba(74, 118, 240, 0.2), rgba(157, 78, 221, 0.1));
    border-color: var(--accent);
    box-shadow: 0 0 0 1px var(--accent), 0 10px 30px rgba(74, 118, 240, 0.3);
}
.os-btn.selected::after { opacity: 1; }
.os-btn svg {
    width: 22px; height: 22px;
    stroke: var(--accent);
    fill: none;
    stroke-width: 1.8;
    stroke-linecap: round;
    stroke-linejoin: round;
    flex-shrink: 0;
    position: relative;
    z-index: 1;
}
.os-btn span { position: relative; z-index: 1; }
.os-btn.linux { grid-column: 1 / -1; justify-content: center; }

/* === OS DETAILS === */
.os-details {
    background: rgba(0, 0, 0, 0.35);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 16px;
    padding: 22px;
    margin-bottom: 4px;
    animation: stepIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}
.os-title {
    font-size: 13px;
    color: var(--text-subtle);
    margin-bottom: 16px;
    font-weight: 600;
    letter-spacing: 0.3px;
}

/* === DOWNLOAD CARDS === */
.dl-list { display: flex; flex-direction: column; gap: 10px; margin-bottom: 16px; }
.dl-card {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 16px;
    background: linear-gradient(135deg, rgba(74, 118, 240, 0.06), rgba(157, 78, 221, 0.06));
    border: 1px solid rgba(74, 118, 240, 0.15);
    border-radius: 14px;
    color: #fff;
    text-decoration: none;
    transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    overflow: hidden;
}
.dl-card:hover {
    border-color: rgba(74, 118, 240, 0.5);
    transform: translateX(3px);
    box-shadow: 0 8px 24px rgba(74, 118, 240, 0.15);
}
.dl-icon {
    width: 40px; height: 40px;
    border-radius: 10px;
    background: rgba(74, 118, 240, 0.12);
    border: 1px solid rgba(74, 118, 240, 0.25);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}
.dl-icon svg {
    width: 18px; height: 18px;
    fill: none;
    stroke: var(--accent);
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}
.dl-info { flex: 1; min-width: 0; }
.dl-name { font-size: 14px; font-weight: 700; margin-bottom: 2px; }
.dl-meta {
    font-size: 11px;
    color: var(--text-dim);
    font-family: 'SF Mono', Menlo, monospace;
    letter-spacing: 0.3px;
}
.dl-arrow {
    width: 18px; height: 18px;
    fill: none;
    stroke: var(--accent);
    stroke-width: 2;
    opacity: 0.5;
    transition: all 0.25s;
    flex-shrink: 0;
}
.dl-card:hover .dl-arrow { opacity: 1; transform: translate(2px, -2px); }

/* === TERMINAL === */
.terminal {
    background: #0d1117;
    border: 1px solid var(--border);
    border-radius: 12px;
    overflow: hidden;
    margin: 16px 0 0;
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.5), inset 0 1px 0 rgba(255, 255, 255, 0.04);
}
.terminal-header {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    background: rgba(0, 0, 0, 0.5);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}
.term-dots { display: flex; gap: 6px; }
.term-dot { width: 10px; height: 10px; border-radius: 50%; box-shadow: inset 0 0 2px rgba(0, 0, 0, 0.5); }
.term-dot.red { background: #ff5f56; }
.term-dot.yellow { background: #ffbd2e; }
.term-dot.green { background: #27c93f; }
.term-title {
    font-family: 'SF Mono', Menlo, monospace;
    font-size: 11px;
    color: #6e7681;
    flex: 1;
    text-align: center;
    letter-spacing: 0.5px;
}
.term-copy-btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border);
    color: var(--text-subtle);
    font-family: 'SF Mono', Menlo, monospace;
    font-size: 10px;
    padding: 4px 10px;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
    text-transform: lowercase;
    letter-spacing: 0.5px;
}
.term-copy-btn:hover {
    background: rgba(74, 118, 240, 0.15);
    border-color: rgba(74, 118, 240, 0.4);
    color: var(--accent);
}
.term-copy-btn.copied {
    background: rgba(39, 201, 63, 0.15);
    border-color: rgba(39, 201, 63, 0.4);
    color: #27c93f;
}
.terminal-body {
    padding: 16px 18px;
    font-family: 'SF Mono', Menlo, Monaco, Consolas, monospace;
    font-size: 12.5px;
    line-height: 1.75;
    color: #e6edf3;
    overflow-x: auto;
}
.term-line { white-space: nowrap; display: flex; gap: 8px; align-items: center; }
.term-line.blank { height: 8px; }
.term-prompt { color: #27c93f; font-weight: 700; user-select: none; flex-shrink: 0; }
.term-comment { color: #6e7681; font-style: italic; }
.cmd-sudo { color: #ff7b72; font-weight: 500; }
.cmd-pkg { color: #ffd93d; font-weight: 500; }
.cmd-flag { color: #79c0ff; }
.cmd-file { color: #ffa657; }

/* === CAPTCHA === */
.captcha-wrap { display: flex; justify-content: center; margin-bottom: 20px; }

/* === KEY BOX === */
.key-box {
    background: rgba(0, 0, 0, 0.5);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 14px;
    padding: 16px;
    font-family: 'SF Mono', Menlo, monospace;
    font-size: 11px;
    line-height: 1.7;
    color: var(--text-subtle);
    word-break: break-all;
    margin-bottom: 12px;
    max-height: 140px;
    overflow-y: auto;
}

.hint {
    color: #505060;
    font-size: 12px;
    line-height: 1.6;
    text-align: center;
    margin-top: 14px;
}

.step-content .btn { margin-top: 16px; }

.fade-out { animation: fadeOut 0.5s ease forwards; }
@keyframes fadeOut { to { opacity: 0; transform: scale(0.98); } }

@media (max-width: 480px) {
    body {
        padding: 16px;
    }
    .reg-card {
        padding: 24px 18px;
        max-width: 100%;
    }
    .reg-card h1 {
        font-size: 22px;
    }
    .step-sub {
        font-size: 13px;
    }
    .step-dot {
        width: 28px;
        height: 28px;
        font-size: 12px;
    }
    .step-line {
        width: 16px;
    }
    .os-grid {
        gap: 8px;
    }
    .os-btn {
        padding: 12px;
        font-size: 13px;
    }
    .os-btn svg {
        width: 18px;
        height: 18px;
    }
    .os-details {
        padding: 16px;
    }
    .dl-card {
        padding: 12px;
        gap: 10px;
    }
    .dl-icon {
        width: 34px;
        height: 34px;
    }
    .dl-icon svg {
        width: 16px;
        height: 16px;
    }
    .dl-name {
        font-size: 13px;
    }
    .dl-meta {
        font-size: 10px;
    }
    .terminal-body {
        font-size: 11px;
        padding: 12px;
    }
    .key-box {
        padding: 12px;
        font-size: 10px;
    }
    .hint {
        font-size: 11px;
    }
}